What are Probiotics?
At birth, the sterile human gut is immediately colonized with several types of microorganisms from both the mother and the environment. By the time they reach one year of age, each individual develops a unique bacterial profile .
It is estimated that only 10% of the cells in the human body actually belong to the body itself. The overwhelming majority of the cells consist of the diverse microbiota of nonpathogenic bacteria, 1-2 kg of them living in the gut alone .
Gut microbiota includes ~30 species of Bifidobacterium, 52 species of Lactobacillus, and others, such as Streptococcus and Enterococcus .
The genome of the entire gut microbiota named as “microbiome” exceeds the human nuclear genome by at least 100 times .
Human gut microorganisms are strongly involved in diverse metabolic, nutritional, physiological, and immunological processes . They play an important role in energy homeostasis and through the microbe-gut-brain axis  by impacting our mood and cognitive abilities. They also stimulate the immune response, prevent pathogenic and opportunistic microbes/bacteria, and produce vitamins such as B and K .
Diet can exert a profound effect on the gut microbiota profile, and people in different parts of the world have different bacterial profiles . For example, there is an association of Bacteroides and high animal fat or protein diets, while Prevotella is associated with a high carbohydrate diet .
Probiotic bacteria are live microorganisms known as “friendly gut bacteria” which when present and/or administered in adequate amounts can have potential health benefits .
The term “probiotic” comes from the Greek term ‘for life’ .
Probiotics have been regarded as beneficial since ancient times (particularly lactic acid bacteria – Lactobacilli and Bifidobacteria), but they came into the spotlight in the late 1800s and early 1900s, when it was proposed that consuming yogurt containing Lactobacillus would decrease toxin-producing bacteria in the gut and increase longevity .
The most common probiotic strains belong to the species Lactobacillus and Bifidobacterium, followed by the genera Streptococcus, Enterococcus, Propionibacterium, Bacillus, and Escherichia. In addition, some yeast species are used as probiotics, for example, S. boulardii and S. cerevisiae [7, 1].
Probiotics can enhance the immune system, improve the skin’s function, enhance resistance against allergens, and decrease body pathogens . They have anti-inflammatory effects, they improve blood lipid profile and glucose tolerance , and lower blood pressure and the BMI .
Note that in clinical studies, probiotic mixtures are often demonstrated to be better than a single strain for improving indigenous microflora .
Prebiotics are specific carbohydrates, such as polysaccharides, fructans, and inulins, that can exert beneficial effects on the composition and metabolic activities of gut microorganisms. A diet high in inulin and related fibers, for example, has been shown to increase Bifidobacteria .
A prebiotic and probiotic combination is referred to as a Synbiotic when the net health benefit is synergistic .
Health Benefits of Probiotics
1) Can Increase Vitamin Levels
Folate-rich fermented milk produced by high-folate-producing S. thermophilus increases hemoglobin levels in mice .
2) Can Increase Iron Levels
Iron deficiency in young women in south India was associated with low levels of Lactobacilli .
3) Can Increase Minerals
4) Act as Antioxidants
A B. subtilis signal molecule induces the heat shock protein Hsp27 in mammalian cells, which protects intestinal cells against oxidant-mediated tissue damage .
5) Maybe Neuroprotective
The probiotic you want: C. butyricum
C. butyricum, furthermore, restores butyrate in the brain, reduces neuronal cell death, and significantly attenuates cognitive dysfunction and histopathological changes in mice with vascular dementia .
C. butyricum also exerts neuroprotective effects against ischemia/reperfusion injury in mice  and attenuates cognitive impairment, cell damage and neuronal death in diabetic mice with cerebral ischemia/reperfusion injury .
6) May Improve Cognitive Function
Try: L. helveticus
Gut probiotics play a major role in the bidirectional communication between the gut and the brain , referred to as the “microbiota-gut-brain” axis. It is now generally accepted that microbiota can affect behavior and modulate cognitive function .
Probiotics improve both spatial and non-spatial memory . Probiotics administration considerably improved the impaired spatial memory and efficiently reversed deteriorated brain in diabetic rats [43, 6].
Germ-free mice display deficits in non-spatial and working memory. Also, mice that were exposed to gut bacterial infection and stress exhibited memory deficits, while probiotic treatment 7 days before and during the infection prevented cognitive dysfunction .
L. plantarum was shown to improve learning and memory in rats with vascular dementia, by acting as a blood pressure-lowering and neuroprotective agent .
Finally, L. casei potentiates the effect of proanthocyanidins extracted from lotus seedpod and ameliorates memory impairments in mice .
7) Improve our Mood
The vast assemblage of microorganisms in our intestines may have a major impact on our state of mind . Gut microorganisms are able to produce and deliver such neuroactive substances as serotonin and gamma-aminobutyric acid (GABA) .
A multispecies probiotic containing B. bifidum, B. lactis, L. acidophilus, L. brevis, L. casei, L. salivarius, and L. lactis reduces cognitive reactivity to a sad mood in non-depressed individuals, which was largely accounted for by reduced rumination and negative thoughts .
An inverse association between constipation and feelings of calmness, elatedness, and agreeableness was found, i.e. frequent constipation was associated with a poorer mood state. A probiotic multivitamin compound significantly improved the general condition of those who participated in the study with a 41% improvement in stress, a 29% decrease in the prevalence of infection and a 91% reduction in GI discomfort .
Probiotic yogurt improved the mood of those with an initially poor mood .
Consuming a probiotic yogurt or a multispecies probiotic capsule for six weeks had beneficial effects on the mental health biomarkers of petrochemical workers .
8) Combats Depression
A correlation was found between human microbiota and depression. Probiotics significantly decreased depression scores in both healthy individuals and patients with major depressive disorder under 60 years of age .
L. helveticus and B. longum reduced depression in healthy volunteers when they were taken regularly .
A mix of L. acidophilus, L. casei and B. bifidum decreased depression, and in addition lowered insulin levels, insulin resistance, and hs-CRP, and increased glutathione levels in patients with major depressive disorder .
Chronic administration of B. infantis protects rats from depressive symptoms caused by stress induced through maternal separation .
9) Reduce Anxiety
Try L. helveticus and/or B. longum
Infecting healthy mice with pathogenic bacteria stimulates anxiety behaviors within hours of infection suggesting that changes in the gut microbiota can very quickly induce biochemical changes in the brain .
L. helveticus and B. longum decreased anxiety and anger/hostility in human volunteers .
10) May Alleviate OCD
11) May Ameliorate Autism
There is a potential role of intestinal microorganisms in the complex pathophysiology of autism spectrum disorder (ASD). Treatment of an autism mouse model with probiotics ameliorated ASD-related traits .
In an animal model of social deficits in offspring, L. reuteri was found to be 9X lower. Supplementing with it increased oxytocin levels and significantly improved sociability and preference for social novelty in mice offspring .
12) May be Beneficial in Schizophrenia
13) Combat Stress
Stressed out? Try: L. casei and/or B. bifidum
In stressed rats, L. casei suppressed blood corticosterone levels .
Similarly, when L. casei was administered to medical students undertaking an authorized nationwide examination to test their response to stress, this bacterium increased serotonin levels, lowered the rate of subjects experiencing common abdominal and cold symptoms and decreased the total number of days students experienced these symptoms .
In academically stressed undergraduate students, B. bifidum increased the proportion of healthy days per participant and decreased the percentage of participants reporting cold/flu during the intervention period .
Similarly, B. bifidum reduced self-reported stress and stress associated diarrhea/GI discomfort in undergraduate students .
14) Improve the Sleep-Wake Cycle
L. helveticus-fermented milk significantly improved sleep efficiency in healthy elderly people .
Daily voluntary wheel-running and sleep rhythmicity became intensified in mice when heat-killed L. brevis was added to the diet .
15) Can Reduce Weight
Look for: L. rhamnosus and/or L. gasseri
Consuming probiotics can reduce body weight and BMI. A greater effect is achieved in overweight subjects, when multiple species of probiotics are consumed in combination or when they are taken for more than 8 weeks .
L. gasseri significantly decreased body weight and visceral and subcutaneous fat areas in adults with obese tendencies .
Despite there being no change in behavior or diet, administration of L. gasseri modestly reduced weight and waist and hip circumference in obese and overweight adults .
L. gasseri significantly decreased BMI, abdominal visceral fat, waist and hip circumferences, and body fat mass in healthy Japanese adults. However, constant consumption of this probiotic may be required to maintain this effect .
16) Combat Obesity
Intestinal microbiota can affect host adiposity and regulate fat storage .
Bifidobacteria content was higher in children of normal weight than those who were showing signs of becoming overweight . Similarly, the presence of B. animalis was found to be negatively associated with BMI in humans [78, 79].
The intake of synbiotics (probiotics + prebiotics) in obese children resulted in a significant reduction in BMI, waist circumference, and some cardiometabolic risk factors, such as TC, LDL-C, and TAG .
Daily ingestion of milk containing B. animalis ssp. lactis significantly reduced the BMI, total cholesterol, low-density lipoprotein, and inflammatory markers in humans .
B. breve lowered fat mass and improved GGT and hs-CRP in adults with obese tendencies .
L. rhamnosus improved liver parameters in obese children with liver dysfunction noncompliant with lifestyle interventions .
L. paracasei decreases energy/food intake in both human and animal subjects .
Oral administration of B. longum, B. bifidum, B. infantis, and B. animalis decreased glucose levels, ameliorated insulin resistance and reduced the expressions of inflammatory adipocytokines in obese mice .
B. breve reduced body weight gain and accumulation of visceral fat in a dose-dependent manner, and improved serum levels of total cholesterol, fasting glucose and insulin in a mouse model of diet-induced obesity .
C. butyricum reduced fat accumulation in liver and blood, lowered insulin levels and improved glucose tolerance and insulin sensitivity in obese mice. Furthermore, C. butyricum administration ameliorated GI and fat tissue inflammation .
Water extract of L. paracasei reduced body weight in obese rats. It decreased the formation of lipid plaques in the aorta, reduced fat cell size and inhibited fat absorption, thereby reducing fat production (lipogenesis) .
NOTE: Although some studies show beneficial effects of L. reuteri in obesity-related symptoms, in one study, this species was associated with obesity in humans .
17) Reduce Glucose and Improve Insulin Sensitivity
L. plantarum reduced glucose levels in postmenopausal women .
L. plantarum caused a significant reduction of blood glucose levels in response to insulin in mice on a high-fat-diet .
18) Are Beneficial in Diabetes
Gut microbiota plays important roles in the pathogenesis and metabolic disturbances of type 2 diabetes mellitus (T2DM) .
Gut microbiota of adults with T2DM is quite different from the microbiota of nondiabetic adults. The content of Bifidobacteria is decreased, whereas Enterococci and Escherichia coli are increased significantly .
In T2DM patients, L. acidophilus and B. animalis increase good cholesterol (HDL-C) levels and decrease the LDL-C/HDL-C ratio . They further significantly decrease fasting blood glucose and exert antioxidant properties .
A synbiotic containing L. acidophilus, L. casei, B. bifidum, and inulin decreased fasting plasma glucose, blood insulin concentrations and increased insulin sensitivity in overweight diabetic patients with coronary heart disease. In addition, HDL-cholesterol levels were increased .
L. acidophilus preserved insulin sensitivity in men with T2DM .
Soy milk containing L. plantarum has antioxidative properties and decreases DNA damage in patients with T2DM .
Diabetic patients who develop foot ulcers are at more risk of dying prematurely than those without the complication. B. subtilis shows antimicrobial activity against four diabetic foot ulcer bacterial pathogens .
B. animalis ssp. lactis reduces weight gain and fat mass, improves glucose tolerance , decreases fasting insulin and blood glucose, and significantly improves insulin tolerance in mice with diabetes .
B. bifidum decreased fasting blood glucose and insulin in diabetic rats .
B. bifidum can stabilize blood sugar, lower cholesterol levels in serum, and improve metabolic activity in mice .
L. brevis decreases glucose levels in diabetic rats .
L. gasseri decreases blood glucose and improves glucose sensitivity in diabetic mice .
Administration of L. casei and B. bifidum alone and in combination ameliorated hyperglycemia, dyslipidemia, and oxidative stress in diabetic rats .
L. casei significantly improved glucose intolerance, dyslipidemia, immune-regulatory properties, and oxidative stress in mice with T2D .
Treating diabetic mice with inviable L. salivarius reversed gut microbial imbalance, restored mucosal antibacterial protein and lessened endotoxin levels .
L. rhamnosus exerts an anti-diabetic effect in mice, with an anti-hyperglycemic effect in several rodent models. L. rhamnosus further improves glucose tolerance and enhances insulin sensitivity .
Treatment with L. plantarum favorably regulates blood glucose, hormones, and lipid metabolism in diabetic rats .
19) Reduce Bad Cholesterol
Daily consumption yogurt containing L. acidophilus after each dinner contributes to a significant reduction in cholesterol . However, it was shown that L. acidophilus does not lower blood cholesterol in men and women with normal to borderline high cholesterol levels .
Buffalo milk yogurt and soymilk yogurt with B. longum decreased total cholesterol by 50%, LDL- cholesterol by 56%, and triglycerides by 51% .
In one study, L. reuteri reduced LDL cholesterol by 11.64%, reduced total cholesterol by 9.14%, non-HDL-cholesterol by 11.30% and apoB-100 by 8.41% . In another study, L. reuteri reduced LDL by 8.92% and total cholesterol by 4.81% .
6-week supplementation of L. salivarius along with fructooligosaccharide (FOS) significantly reduced total cholesterol, “bad” (LDL) cholesterol, and triglycerides .
B. longum reduced total cholesterol, particularly among subjects with moderate hypercholesterolemia .
L. fermentum modestly improved cholesterol in a clinical study .
In another study, a combination of bacteria strains more effectively reduced total cholesterol and liver cholesterol compared to individual bacteria strains .
B. animalis, B. bifidum, and B. longum reduced total cholesterol and LDL-C in children with primary dyslipidemia .
Milk fermented with L. acidophilus and B. longum significantly reduced LDL cholesterol in hypercholesterolemic women .
In overweight subjects, the administration of capsules with Bifidobacteria, Lactobacilli, and S. thermophilus significantly improved lipid profiles, reducing total cholesterol (TC), triacylglycerols (TAG), and LDL-C levels .
See individual probiotic posts for more information and animal studies.
20) Increase Good Cholesterol
Probiotics can increase high-density lipoprotein-cholesterol (HDL-C) .
In T2DM patients, L. acidophilus and B. animalis increase good cholesterol (HDL-C) levels .
A synbiotic containing L. acidophilus, L. casei, B. bifidum, and inulin increased HDL-cholesterol in diabetic subjects .
A synbiotic shake containing L. acidophilus, B. bifidum and fructo-oligosaccharides significantly increased HDL-C in elderly people with diabetes .
6-week supplementation of L. salivarius along with fructooligosaccharide (FOS) significantly increased “good” (HDL) cholesterol in healthy young volunteers .
In overweight subjects, Bifidobacteria, Lactobacilli, and S. thermophilus significantly improved HDL-C .
B. coagulans increased good cholesterol in diabetic patients .
L. plantarum increased “good” (HDL) cholesterol in mice .
B. bifidum increased HDL in diabetic rats .
21) Reduce Blood Pressure
Try: L. helveticus
L. helveticus produces angiotensin-converting enzyme (ACE)-inhibitory peptides that can prevent or control high blood pressure .
Daily ingestion of the tablets containing powdered fermented milk with L. helveticus in subjects with high-normal blood pressure or mild hypertension reduces elevated blood pressure without any adverse effects .
Long-term treatment with L. helveticus-fermented milk reduces arterial stiffness in hypertensive subjects .
L. faecium and S. thermophilus reduced systolic BP in overweight and obese subjects .
22) Are Beneficial in Metabolic Syndrome
B. animalis ssp. lactis significantly reduced BMI, total cholesterol, low-density lipoprotein and inflammatory cytokines in patients with metabolic syndrome .
L. plantarum reduced total cholesterol, LDL-cholesterol, glucose and homocysteine levels in postmenopausal women with metabolic syndrome .
L. casei improved insulin sensitivity in subjects with metabolic syndrome .
23) Prevent Cardiovascular Disease
Probiotics and prebiotics have preventative and therapeutic effects on cardiovascular disease due to a reduction in total serum cholesterol, low-density lipoprotein (LDL-cholesterol), and inflammation .
Daily supplementation with S. boulardii lowered remnant lipoprotein in hypercholesterolemic adults, a predictive biomarker and potential therapeutic target in the treatment and prevention of coronary artery disease .
L. acidophilus consumption led to 2.4% to 3.2% reduction in blood cholesterol in clinical studies. Since every 1% reduction in serum cholesterol concentration is associated with an estimated 2% to 3% reduction in risk for coronary heart disease, regular intake of L. acidophilus has the potential of reducing the risk for coronary heart disease by 6 to 10% .
L. acidophilus can protect against atherosclerosis through the inhibition of intestinal cholesterol absorption in mice fed a Western diet .
Lipoteichoic acid (LTA) from L. plantarum inhibits the production of proinflammatory cytokines and suppresses atherosclerotic plaque inflammation in mice .
L. acidophilus reduces cholesterol and inhibits the accumulation of lipoprotein in atherosclerotic plaques in mice .
24) Improve Our Gut Health
Probiotics can decrease the number of potentially pathogenic gastrointestinal microorganisms and pathogens, reduce gastrointestinal discomfort, flatulence and bloating, and improve bowel regularity .
4 weeks’ supplementation with B. animalis ssp. lactis resulted in a clinically relevant benefit on defecation frequency in healthy adults with abdominal discomfort .
Ingestion of B. bifidum significantly decreased the prevalence of gastric and lower abdominal symptoms in adults taking no medication .
Beneficially Modify Gut Microbiota
Probiotics, in general, tend to increase the levels of Lactobacilli and Bifidobacteria in the gut, while decreasing the levels of potentially pathogenic microorganisms [157, 158, 159, 160, 161, 162, 163, 164, 165, 166, 167, 168, 169].
Check individual probiotic posts for more information.
Strengthen the Intestinal Barrier
The intestinal barrier separates the contents of the gut from the rest of the body. This barrier prevents the entry of harmful substances such as foreign antigens, toxins, and microorganisms. Hyperpermeability of this barrier (“leaky gut”) contributes to the pathogenesis of several gastrointestinal disorders including IBD, Celiac disease and food allergy .
In humans, L. rhamnosus protects against disruption of the gastric mucosal barrier .
Fermented milk with L. paracasei promotes intestinal epithelial cell growth and intestinal epithelial integrity and strengthens the intestinal barrier against chemical and inflammatory stimuli-induced damage .
In rats, B. bifidum or B. animalis protect the mucous membrane layer of the stomach .
S. cerevisiae strengthens epithelial barrier function . Oral treatment with viable or heat-killed S. cerevisiae strain prevents bacterial translocation, protects intestinal barrier integrity, and stimulates immunity in mice with intestinal obstruction .
Prevent and Ameliorate Drug-Induced GI Damage
Probiotics maintain an individual’s intestinal microbiota in subjects receiving antibiotic treatment .
L. acidophilus administered with amoxicillin/clavulanate was associated with a significant decrease in patient complaints of GI side effects and yeast superinfection .
L. casei is effective for the treatment of aspirin-associated small bowel injury in chronic low-dose aspirin users .
Long-term L. rhamnosus supplementation has an influence on the composition of the intestinal microbiota in children, and reduces the frequency of gastrointestinal complaints after antibiotic use, preventing certain bacterial infections for up to 3 years after the trial .
L. delbrueckii microcapsules relieve intestinal tissue damage in mice and ameliorate antibiotic-induced intestinal microbiota dysfunction .
L. paracasei therapy prevents antibiotic induced visceral hypersensitivity and restores normal gut permeability in rats .
B. animalis ssp. lactis protects against NSAID-induced GI side effects in rats and may prevent more serious GI mucosal damage and/or enhance the recovery rate of the stomach mucosa .
S. boulardii significantly reduced the numbers of gastric ulcers and the ulceration surface of the gastric mucosa in rats treated with ibuprofen .
Ameliorate Gastric Ulcers
Probiotics inhibit the development of acute gastric mucosal lesions and accelerate gastric ulcer healing .
Lactobacilli are particularly useful in promoting gastric ulcer healing in rats when administered as an individual probiotic strain, such as L. rhamnosus, L. gasseri, or L. acidophilus or as a probiotic mixture [4, 4, 4, 185, 186, 4].
B. breve and B. bifidum were able to repair and protect the mucosa of rats against gastric ulcers and erosions .
Pretreatment of mice with gastric ulcers with the probiotic C. butyricum alleviated the inflammation and gastric mucosal damage .
Certain yeasts, such as S. boulardii and S. cerevisiae have also shown beneficial effects in rats with gastric ulcers .
Prevent and Treat Diarrhea
Use of probiotics in antibiotic-associated diarrhea decreased the risk of diarrhea by 52%, traveler’s diarrhea by 8%, and acute diarrhea from various causes by 34%. Probiotics were more effective in reducing the risk of acute diarrhea in children 57% versus 26% in adults .
Acute Infective Diarrhea:
L. acidophilus reduced the duration of diarrhea in hospitalized, but not outpatient, children , and ameliorated both rotavirus-positive diarrhea  and nonrotavirus diarrhea in children .
L. acidophilus and B. bifidum shortened the duration of diarrhea in infants and children .
L. rhamnosus administration was associated with significantly lower rates of and symptomatic rotavirus gastroenteritis diarrhea in hospitalized children .
L. reuteri decreases the incidence of diarrhea in children .
Formula supplemented with B. bifidum and S. thermophilus reduced the incidence of acute diarrhea and rotavirus shedding in infants admitted to hospital .
B. breve together with S. thermophilus reduces the severity of acute diarrhea and dehydration among healthy young infants .
S. boulardii significantly reduces the frequency and duration of acute diarrhea in children [203, 204, 205, 206, 207, 208, 209, 210]. It also often reduces the length of ECU and hospital stay in acute infectious gastroenteritis in children [211, 212].
Treatment with L. rhamnosus reduced the risk of antibiotic-associated diarrhea (AAD) in patients treated with antibiotics from 22.4% to 12.3% .
L. helveticus and L. rhamnosus supplementation significantly reduced the duration of antibiotic-associated diarrhea in healthy adults receiving antibiotics .
B. animalis spp. lactis together with S. thermophilus reduced the frequency of antibiotic-associated diarrhea (AAD) in infants .
Concomitant administration of C. butyricum with antibiotics normalizes the intestinal microbiota, prevents the decrease of Bifidobacteria, and is effective for preventing and treating antibiotic-associated diarrhea in children .
Some studies report that S. boulardii is not effective in preventing the development of antibiotic-associated diarrhea [221, 222, 223, 224]. However, many studies do, in fact, show that S. boulardii is effective in reducing the risk of antibiotic-associated diarrhea in both children and adults [225, 226, 227, 228, 229, 230, 231].
B. subtilis significantly reduced the incidence of antibiotic-associated diarrhea and prevented nausea, bloating, vomiting and abdominal pain .
S. boulardii prevents traveler’s diarrhea, particularly in regions such as North Africa and in the Near-east .
Chemo- and Radiotherapy-induced Diarrhea:
Probiotics may have a beneficial effect on the prevention of chemo- and radiotherapy-induced diarrhea, where they rarely cause adverse effects .
See individual probiotic posts for more information and animal studies.
B. breve is effective in diminishing abdominal pain and increasing stool frequency in children with functional constipation .
A combined regimen of lactulose and live binary B. subtilis is an effective and safe therapeutic method for elderly with functional constipation .
See individual probiotic posts for more information and animal studies.
Probiotics Combat IBS
L. plantarum reduces gas problems and pain in people who suffer from irritable bowel syndrome .
Probiotics containing L. plantarum and B. breve in IBS patients decreased pain by 38% in the probiotic group compared with 18% in the placebo group, and after 28 days, the pain was decreased 52% in the probiotic group compared with 11% in the placebo group .
L. rhamnosus has been proven to reduce symptoms in children with functional gastrointestinal disorders .
L. rhamnosus, L. reuteri and VSL#3 significantly increased treatment success for functional gastrointestinal disorders (FGIDs) in children and adolescents .
A mixture of B. infantis, B. breve, and B. longum improve abdominal pain and the quality of life in children with irritable bowel syndrome (IBS) .
B. bifidum significantly improved the pain/discomfort, distension/bloating, urgency and digestive disorder in patients with IBS .
Fermented milk containing B. bifidum improves symptoms in patients with functional gastrointestinal disorders (FGID). Abdominal pain, diarrhea, and constipation significantly improved, as did acid-related dyspepsia. Psychological symptoms such as anger and hostility also improved .
B. animalis has a beneficial effect on discomfort, bloating and constipation in constipation-predominant IBS patients .
B. coagulans decreased bloating, vomiting, diarrhea, abdominal pain, and stool frequency and increased the quality of life in patients with the diarrhea-predominant irritable bowel syndrome (IBS) [261, 262, 263, 264].
A combination of simethicone and B. coagulans reduced bloating and discomfort in patients with IBS .
L. brevis improves the quality of life, reduces diarrhea and abdominal pain and increases Bifidobacteria in patients with IBS .
In one clinical trial, S. cerevisiae reduced abdominal pain and discomfort in subjects with IBS . In another trial, however, S. cerevisiae had no beneficial effect on IBS symptoms and wellbeing. However, it seemed to have some effect in the subgroup with constipation .
A combination product designated VSL#3, which contains large quantities of 8 bacterial species, was shown to significantly improve IBS symptoms .
Probiotics Ameliorate IBD
B. longum ameliorated ulcerative colitis symptoms in Japanese patients .
S. boulardii added to baseline therapy improved intestinal permeability in Crohn’s disease (CD) patients, even though complete normalization was not achieved . This probiotic also reduced the frequency of bowel movements in CD patients .
P. freudenreichii was effective in the treatment of mild to moderate ulcerative colitis in a human pilot study .
In Asian studies involving patients with ulcerative colitis, the addition of a B. subtilis probiotic significantly reduced the number of days with bloody stool, led to complete remission without relapse, and significantly increased the efficacy of mesalazine or sulfasalazine therapy .
L. plantarum ameliorates ulcerative colitis in mice via both anti-inflammatory and immunomodulatory activities  and decreases the severity of intestinal inflammation in mice with inflammatory bowel disease (IBD) .
B. bifidum decreases symptoms of inflammatory bowel disease (IBD) in mice, such as thickened intestinal wall and inflammatory cell infiltration, and decreased inflammatory cytokine production .
Other probiotics that were effective in ameliorating colitis in animal models include L. casei [280, 281], L. paracasei , L. salivarius , L. delbrueckii ssp. bulgaricus , L. delbrueckii ssp. lactis , L. helveticus , B. longum , B. animalis ssp. lactis [288, 289, 290], C. butyricum [291, 292, 293], B. coagulans [294, 295], L. brevis [296, 297, 298], L. fermentum [299, 300, 301, 302], S. boulardii , L. lactis [304, 305, 306, 307], S. thermophilus , P. freudenreichii [164, 309, 310], B. subtilisis [311, 312, 313, 314] and S. cerevisiae [315, 316].
Check individual probiotic posts for more information.
Probiotics Ameliorate Necrotizing Enterocolitis
Oral supplementation of L. paracasei reduced the clinical progression of necrotizing enterocolitis in infants .
Prophylactic L. acidophilus and B. infantis reduced the incidence and mortality of necrotizing enterocolitis (NEC) in infants .
B. breve was associated with decreased risk of necrotizing enterocolitis in neonates .
Oral administration of B. breve reduces the production of butyric acid in infants, which may be helpful in protecting low birth weight infants from digestive diseases such as necrotizing enterocolitis .
However, one study found no benefit in B. breve administration for prevention of necrotizing enterocolitis and late-onset sepsis in very preterm infants .
B. breve suppresses inflammation, reduces the pathology and increases survival in rats with necrotizing enterocolitis .
Probiotics Ameliorate Diverticular Disease
L. paracasei, in association with a high-fiber diet, is effective in reducing abdominal bloating and prolonged abdominal pain in patients with symptomatic uncomplicated diverticular disease .
25) Boost Immunity
Gut microbiota cooperate with the host immune system through an extensive array of signaling pathways .
Studies with germ-free animals show that microbiota is necessary for the development and regulation of immunity in the gut, where it prevents the development of inappropriate inflammation .
L. paracasei, L. delbrueckii, L. fermentum, L. lactis, L. gasseri, B. longum, B. breve, B. animalis and other probiotics were shown to skew the Th1/Th2 balance toward Th1 [340, 341, 342, 343, 344, 345, 346, 347, 348, 349] in infections and allergies.
Probiotics Combat Infections
L. paracasei prevents common infectious disease (CIDs) in children attending daycare .
L. helveticus supplementation significantly shortened the duration and decreased the number of symptoms of upper respiratory tract illness in athletes, and increased their sense of vigor .
Fermented milk containing L. johnsonii suppressed infections in the elderly .
L. brevis reduces the incidence of influenza in elementary schoolchildren. The improvement is especially pronounced in unvaccinated individuals .
S. boulardii enhances the immune response in pediatric acute gastroenteritis .
Yogurt fermented with L. lactis lowers the risk of the common cold in human subjects .
Fermented milk containing L. rhamnosus was efficient in reducing the risk of respiratory tract infections that lasted longer than three days in hospitalized children .
Preterm infants treated daily with L. rhamnosus in capsules starting within one week after birth, appear to have a significantly lower incidence of respiratory tract infections (RTIs) and rhinovirus-induced episodes in the first 2 months .
Consumption of L. rhamnosus reduced the occurrence of respiratory illness in children attending daycare centers .
Children receiving L. rhamnosus probiotics had fewer days with respiratory symptoms per month than the children in the control group .
Capsulated L. rhamnosus was shown to protect hospitalized patients against ventilator-associated pneumonia, mainly when caused by Gram-negative pathogens like Pseudomonas aeruginosa .
In cystic fibrosis patients with P. aeruginosa, long-term L. rhamnosus significantly decreased the incidence of pulmonary exacerbations and increased body weight .
L. casei significantly lowered the incidence and duration of upper respiratory tract infections (URTIs) in healthy middle-aged office workers .
Similarly, in healthy shift workers, L. casei decreased the incidence of gastrointestinal and respiratory common infectious disease (CIDs), increased the time to the first occurrence of CID, and reduced the total number of CIDs in the subgroup of smokers. In the course of CID, the total duration of fever was lower and an increase in leukocyte, neutrophil, and natural killer (NK) cell counts and activity was observed .
L. casei also lowered the incidence of common infectious diseases (CIDs) in children , decreased the duration of CID, and especially upper-respiratory-tract infections (URTI) such as rhinopharyngitis in the elderly .
In athletic men and women who engaged in endurance-based physical activities in winter, L. casei lowered the proportion of subjects who experienced 1 or more weeks with upper-respiratory-tract infection (URTI) symptoms and decreased the number of URTI episodes .
When healthy subjects took L. gasseri, B. longum, and B. bifidum in the winter, common cold episodes shortened by almost 2 days and reduced the severity of symptoms .
L. acidophilus, B. bifidum and B. animalis plus vitamin C reduced the incidence rate of upper respiratory tract infection, the number of days with symptoms and the absence from preschool in children .
A synbiotic containing L. acidophilus, B. infantis, and B. bifidum can provide effective control of respiratory infection and wheezing frequency in children under five years old .
L. acidophilus suppressed all of the 74 gram-negative and 16 of gram-positive bacteria found in burn wounds, that can cause burn wound infections .
L. fermentum reduced the duration and severity of respiratory illness in highly trained distance runners .
L. fermentum reduced the severity of gastrointestinal and respiratory illness symptoms in male but not female cyclists .
Oral administration of L. fermentum potentates the immunologic response of an anti-influenza vaccine and may provide enhanced systemic protection by increasing the Th1 response and virus-neutralizing antibodies. The incidence of an influenza-like illness for 5 months after vaccination was decreased in the group that consumed this probiotic [343, 344].
B. longum reduces the incidence of influenza and fever in subjects with influenza vaccination .
B. longum fed infants showed a trend toward fewer respiratory tract infections .
B. longum ssp. infantis triggers the anti-poliovirus response in infants .
B. breve significantly inhibited rotavirus multiplication and prevented rotavirus infection in infants .
B. animalis ssp. lactis reduces days with cold/flu in young healthy adults .
S. boulardii reduces E. coli numbers in children .
S. boulardii can treat B. hominis infection in children as efficiently as metronidazole .
S. boulardii was effective in treating giardiasis when combined with metronidazole therapy in adult patients .
The addition of S. boulardii to metronidazole in amebiasis significantly decreases the duration of (bloody) diarrhea and enhances clearance of cysts in children , and decreases the duration of symptoms and cyst passage in adults .
Prophylactic S. boulardii supplementation is as effective as nystatin in reducing fungal colonization and invasive fungal infection, more effective in reducing the incidence of clinical sepsis and the number of sepsis attacks and has a favorable effect on feeding intolerance in very low birth weight infants .
B. subtilis decreased the frequency of respiratory infections in elderly subjects .
B. subtilis inhibits disease transmission in patients with acute non-typhoid Salmonella gastroenteritis .
Metabolites of B. subtilis decrease the resistance of urogenital pathogenic microflora to antibiotics in patients with urinary tract infections, resulting in accelerated elimination .
Probiotics were effective in the treatment and prevention of urogenital infections in women as alternatives or co-treatments. They were effective for treatment and prevention of bacterial vaginosis, prevention of recurrences of candidiasis and urinary tract infections, and clearing human papillomavirus lesions. No study reported significant adverse events related to probiotic intervention .
Probiotic supplementation with vaginal L. rhamnosus is useful in hindering bacteria growth especially after antibiotic therapy .
L. rhamnosus vaginal tablets have demonstrated to be a reliable topical effective and safe treatment to reduce the bacterial vaginosis recurrence rate .
Daily ingestion yogurt, enriched with L. acidophilus may reduce the episodes of bacterial vaginosis . Treatment of patients with bacterial vaginosis with L. acidophilus contributed to the restoration of a normal vaginal environment .
L. fermentum and L. plantarum significantly reduced bacterial vaginosis in women .
L. crispatus reduces recurrent urinary tract infections in premenopausal women .
Cervicovaginal mucus with high L. crispatus concentrations can trap the HIV virus .
B. coagulans reduced vaginosis symptoms in women when co-administered with antibiotics .
See individual probiotic posts for more information and animal studies
26) Can Alleviate Mucositis
Oral mucositis is one of the most common, debilitating complications of cancer treatments, particularly chemotherapy and radiation. L. brevis reduced the incidence and severity of anticancer therapy-induced oral mucositis and improved the tolerance to chemo-radiotherapy, and anticancer treatment completion .
L. acidophilus improved inflammatory and functional aspects of intestinal mucositis caused by chemotherapy in mice .
S. boulardii reduced the inflammation and dysfunction of the gastrointestinal tract in mice with intestinal mucositis .
In one study, S. thermophilus partially alleviated mucositis induced by administration of the antimetabolite chemotherapy drug methotrexate in rats , while in another study no protective effects were observed .
S. thermophilus partially prevented the loss of body weight induced by doxorubicin and slightly ameliorated doxorubicin-induced mucositis in rats .
S. thermophilus significantly reduced intestinal mucositis severity in rats treated with 5-Fluorouracil .
27) Help in Helicobacter pylori Treatment
Frequently used probiotic strains for H. pylori infection are L. johnsonii, S. boulardii, L. acidophilus and B. animalis ssp. lactis .
Probiotics can inhibit H. pylori infection by both non-immunological and immunological mechanisms .
L. delbrueckii ssp. bulgaricus and S. thermophilus improve H. pylori eradication rates in infected patients .
L. acidophilus decreases the viability of H. pylori and increases the eradication rate in infected patients .
Multi-strain probiotics, including L. acidophilus/B. animalis, significantly improve H. pylori eradication rates, prevent adverse reactions and reduce antibiotic-associated diarrhea .
L. gasseri suppressed H. pylori and reduced gastric mucosal inflammation in infected patients . A 4-week treatment with L. gasseri -containing yogurt improved the efficacy of triple therapy in patients with H. pylori infection . L. gasseri yogurt also suppressed dyspeptic symptoms in H. pylori-infected patients .
Fermented milk containing L. johnsonii co-administered with antibiotics was shown to have a favorable effect on H. pylori gastritis .
A 2-week treatment with L. reuteri significantly reduced H. pylori overgrowth in otherwise healthy adults .
B. animalis spp. lactis and inulin significantly reduced treatment side effects and indirectly increased eradication rates by increasing patient compliance in patients with symptomatic H. pylori infection .
B. bifidum improved rates of upper gastrointestinal symptomatic subjects and total symptoms in patients with H. pylori infection .
The combined use of C. butyricum reduced the changes in the intestinal flora and decreased the incidence of gastrointestinal side effects in patients going through H. pylori eradication therapy [420, 421].
L. brevis treatment decreases H. pylori colonization in dyspeptic H. pylori patients and reduces polyamine biosynthesis .
B. subtilis containing probiotics improved H. pylori eradication and decreased diarrhea and total side effects when used in conjunction with triple therapy .
S. boulardii has a positive effect on reducing the colonization of H. pylori in the human gastrointestinal system but is not capable of its eradication when used as single therapy .
In patients with H. pylori infection, there is evidence to recommend the use of S. boulardii along with standard triple therapy as an option for increasing the eradication rates and decreasing overall therapy-related side effects, particularly diarrhea [424, 425, 426, 427, 428, 429].
S. boulardii administered in addition to proton pump inhibitor-based triple therapy nonsignificantly lowered the incidence of nausea, vomiting, and abdominal pain and significantly lowered the incidence of stomatitis, constipation, and diarrhea in infected children .
S. boulardii improved anti-H. pylori therapy-associated diarrhea, epigastric discomfort, and treatment tolerability. In addition, S. boulardii decreased post-treatment dyspepsia symptoms independent of H. pylori status .
L. paracasei supplementation prevents bowel symptom onset in patients on long-term proton pump inhibitors .
28) Reduce Inflammation
Supplementation with a synbiotic, which is a mixture of L. casei, L. rhamnosus, S. thermophilus, B. breve, L. acidophilus, B. longum, L. delbrueckii ssp. bulgaricus, and fructo-oligosaccharides reduces inflammation markers in adults .
B. longum ssp. infantis reduced proinflammatory markers in patients with ulcerative colitis, chronic fatigue syndrome, and psoriasis .
L. casei improved natural killer (NK) cell activity and produced a more anti-inflammatory cytokine profile in healthy non-immunocompromised elderly subjects .
L. paracasei significantly increases the release of pro-inflammatory cytokines and stimulates the innate immune system in human enterocytes and dendritic cells (DCs) .
L. delbrueckii ssp. lactis was shown to possess anti-inflammatory effects . Skimmed milk with L. delbrueckii ssp. bulgaricus inhibits the secretion of proinflammatory cytokines produced by accessory white blood cells .
L. acidophilus alleviates inflammation in human intestinal epithelial cells .
L. animalis ssp. lactis added to yogurt post-fermentation has anti-inflammatory properties in healthy adults .
L. animalis ssp. lactis inhibits inflammation in elderly volunteers .
See individual probiotic posts for animal studies and technical information.
29) Beneficial in Autoimmune Disorders
Probiotics and prebiotics have the potential to curb the autoimmune response and are being considered as an alternative to detrimental immunosuppressive drugs .
Intestinal dysbiosis, characterized by a reduced Firmicutes/Bacteroidetes ratio, has been reported in systemic lupus erythematosus (SLE) patients . B. bifidum supplementation prevents CD4+ lymphocyte over-activation and may help in restoring the Treg/Th17/Th1 imbalance present in patients with SLE .
30) Can Ameliorate Celiac Disease
Try B. longum
B. longum ssp. infantis reduces gastrointestinal symptoms in untreated Celiac disease (CD) patients .
Oral administration of B. longum ameliorates gliadin (gluten)-mediated perturbations in liver iron deposition and mobilization in rats with CD .
B. longum attenuates the production of inflammatory cytokines and the CD4+ T-cell mediated immune response and protects newborn rats against gliadin (gluten)-induced enteropathy .
Live B. animalis ssp. lactis bacteria can directly counteract the harmful effects exerted by celiac-toxic gluten (gliadin) to human intestinal cells .
L. casei induced complete recovery in mice with enteropathy such as Coeliac disease .
31) Beneficial in Liver Disease
Probiotics found in yogurt, L. delbrueckii ssp. bulgaris and S. thermophilus improve liver function .
Probiotics Ameliorate NAFLD
Some probiotics and synbiotics improve liver and metabolic parameters in patients with non-alcoholic fatty liver disease (NAFLD) .
In patients with NAFLD, L. acidophilus and B. lactis reduced serum levels of ALT, ASP, TC, and LDL-C .
In obese children with NAFLD, L. rhamnosus restored liver function .
Bifidobacteria, Lactobacilli, and S. thermophilus treatment for 4 months improved fatty liver severity and decreased BMI of children with NAFLD .
L. rhamnosus protects against NAFLD in mice, by increasing beneficial bacteria in the distal small intestine and attenuating liver fat accumulation and portal alanine-aminotransferase concentrations .
Treatment of L. plantarum for 5-weeks restored liver function in rats with non-alcoholic fatty liver disease (NAFLD) and decreased the levels of fat accumulation in the liver. In addition, the bacterium significantly reduced proinflammatory cytokines .
L. casei protects against the onset of NAFLD in mice , and suppresses nonalcoholic steatohepatitis development, by reducing blood lipopolysaccharide concentrations, suppressing inflammation and fibrosis in the liver, and reducing colon inflammation .
L. paracasei symbiotic (containing arabinogalactan, fructooligosaccharides) lessens NAFLD progression in rats, lowers inflammatory markers and reduces the severity of liver injury and insulin resistance .
L. johnsonii protects mice with NAFLD from liver steatosis and liver cell death .
C. butyricum increases cholesterol degrading enzymes and improves NAFLD in rats on a high-fat diet .
Probiotics are Beneficial in NASH
A synbiotic that contains five probiotics (L. plantarum, L. delbrueckii, L. acidophilus, L. rhamnosus, B. bifidum, and inulin) over 6 months in adults with nonalcoholic steatohepatitis (NASH) produced a significant decrease in intrahepatic triglyceride (IHTG) levels .
B. longum and fructo-oligosaccharides (FOS) significantly reduced AST, CRP, HOMA-IR, blood endotoxin and steatosis in patients with NASH .
L. paracasei lowers liver fat deposition and serum ALT level in mice with NASH .
Probiotics Protect Against Alcohol-Induced Liver Injury
L. casei attenuates alcohol-induced liver cell damage .
In chronic alcohol-induced mice, whey fermented with L. casei significantly attenuates the increased levels of ALT, AST and triglyceride levels, increases antioxidant activity and improves liver parameters .
L. paracasei reduces total blood and liver cholesterol in rats and decreases liver damage due to alcohol intake .
Oral administration of L. brevis ameliorates alcohol-induced liver injury and the fatty liver in mice. It significantly inhibited ALT and AST increase and decreased TG and total cholesterol in the liver .
Probiotics May Ameliorate Jaundice
Treatment of obstructive jaundice in rats with L. plantarum returned active liver barrier functions .
Probiotics Protect from Liver Injury
L. plantarum protects against oxidative stress and liver inflammatory injury in mice .
L. casei significantly improved the survival of rats with liver injury, via its anti-oxidative and anti-inflammatory capacities .
Pretreatment with L. salivarius improves acute liver injury in rats .
L. salivarius exerts a good health-promoting effect in acute liver failure .
S. boulardii effectively prevents liver injury induced by Salmonella Enteritidis infection in mice .
Probiotics are Beneficial in Cirrhosis
B. faecium and B. subtilis shift the intestinal microbiota of patients with liver cirrhosis back towards levels observed in healthy subjects. These probiotics also reduce circulating endotoxin levels in cirrhotic patients with endotoxemia .
B. longum and FOS improved biochemical parameters and neuropsychological tests in cirrhotic patients with minimal hepatic encephalopathy (MHE) .
S. boulardii promotes liver function and slows down the progress of liver fibrosis in rats .
32) Combat Allergies
Probiotics harmonize Th1/Th2 imbalance in allergic conditions in adults .
Probiotics May Prevent Systemic Allergies
L. casei protects mice from acute allergic inflammation (anaphylaxis) .
Probiotics May Prevent Allergies in Newborns
Consumption of L. rhamnosus-fermented milk by mothers and offspring showed a reduction in physical allergic symptoms in newborn mice .
Neonatal mother-to-offspring colonization with B. longum reduces allergic responses in mice .
Probiotics are Beneficial in Asthma
L. salivarius decreases the secretion of proinflammatory cytokines and shows beneficial immunomodulatory activity in asthmatic subjects .
B. breve shows promising probiotic properties and beneficial immunomodulatory activity in allergic asthma .
L. lactis significantly attenuates atopic esophageal and bronchoalveolar eosinophilic inflammation in mice .
L. paracasei administration to mothers during gestation/lactation protects against airway inflammation in mice offspring .
B. longum attenuates allergic airway inflammation in mice .
Probiotics Alleviate Allergic Rhinitis
17/22 trials showed a significant benefit of probiotics clinically, whereas eight trials showed significant improvement in immunologic parameters in allergic rhinitis .
Citrus juice fermented by L. plantarum can improve the symptoms of Japanese cedar pollinosis .
C. butyricum can markedly enhance the efficacy of SIT on allergic rhinitis in patients with allergies .
Co-administration of C. butyricum markedly enhances the treatment of allergic rhinitis .
L. rhamnosus supplementation shows good clinical and immunologic response in children with allergic rhinitis .
Volunteers with seasonal allergic rhinitis treated with L. casei showed a significant reduction in levels of antigen-induced cytokines .
A significant reduction of nasal symptoms and improved quality of life were achieved in patients with Japanese cedar pollinosis, who received L. paracasei when pollen scattering was low. However, the effects were limited during the peak period .
Subjects with a medical history of allergic rhinitis to grass pollen that received L. paracasei -fermented milk had lower nasal congestion and nasal itching .
In children with perennial allergic rhinitis, L. paracasei improved symptoms of sneezing, itchy nose, and swollen eyes .
L. paracasei improved the quality of life of subjects with persistent allergic rhinitis who were being treated with an oral H1-antihistamine. In this study, nasal symptoms had not changed, but ocular symptoms had consistently improved .
Heat-killed L. paracasei can effectively improve the overall quality of life in patients with allergic rhinitis induced by house dust mite in human subjects .
L. acidophilus alleviates the symptoms in patients with perennial allergic rhinitis .
Heat-killed L. gasseri improved nasal symptoms and pollen-specific IgE levels in subjects with Japanese cedar pollinosis .
The addition of L. johnsonii to levocetirizine improved perennial allergic rhinitis in children .
Intake of yogurt or powder supplemented with B. longum alleviated subjective symptoms and affected blood markers of allergy in individuals with Japanese cedar pollinosis [514, 515, 516]. Nasal symptoms such as itching, rhinorrhea, and blockage, as well as throat symptoms, tended to be relieved with this probiotic .
B. animalis ssp. lactis improved nasal symptoms in subjects suffering from seasonal allergic rhinitis .
Check individual posts for more information and animal studies.
Probiotics Combat Food Allergies
L. rhamnosus decreased the allergic response to peanuts in children .
In milk-hypersensitive adults, L. rhamnosus has been shown to reduce the immunoinflammatory response .
L. plantarum reduces the allergenicity of soy flour .
L. salivarius, L. paracasei, B. animalis and B. bifidum prevent atopic sensitization to common food allergens and thereby reduce the incidence of atopic eczema in early childhood .
L. delbrueckii ssp. bulgaricus degrades the allergenic whey protein β-lactoglobulin and inhibits IgE binding in allergic patients .
L. helveticus alone or in combination with S. thermophiles effectively reduces the antigenicity of α-lactalbumin and β-lactoglobulin, the major allergens in cow’s milk .
L. fermentum degrades αS1-casein and lowers the recognition and the binding of this casein to IgE from the blood of patients with cow’s milk allergy .
B. breve improves symptoms of allergic hypersensitivity to cow’s milk in infants .
Probiotics Alleviate Eczema
The combination of prenatal maternal (2 – 4 weeks) and postnatal pediatric (6 months) L. rhamnosus treatment in families with a history of atopic disease, significantly lowers the risk of eczema at the age of 2, 4 and 7 .
In infants receiving either L. rhamnosus or B. lactis after 2 months, eczema symptoms were significantly improved .
L. rhamnosus efficiently prevents the development of eczema and possibly also atopic sensitization in high-risk infants up to 6 years old .
Cumulative prevalence of eczema and prevalence of rhinoconjunctivitis were significantly reduced in the children taking L. rhamnosus .
B. animalis ssp. lactis significantly improved eczema symptoms in infants .
When administered to pregnant women with a family history of allergic diseases, a mixture of B. bifidum, B. lactis, and L. acidophilus significantly lowered the prevalence and incidence of eczema in infants at high risk of allergy .
B.breve reduced the risk of developing eczema and atopic sensitization in infants at high risk of allergic disease .
B. bifidum has a positive effect on the prevention and treatment of eczema in infants .
The use of multi-strain probiotics appeared to be most effective for eczema prevention .
Probiotics Prevent Atopic Dermatitis
Use of L. rhamnosus by mothers lowers the risk of developing atopic dermatitis during the first 2 years of life .
L. rhamnosus is effective in decreasing symptoms of atopic dermatitis after an 8-week treatment in children aged 4 – 48 months .
Daily intake of citrus juice containing heat-killed L. plantarum alleviates symptoms of atopic dermatitis in humans .
Heat-killed L. paracasei improved atopic dermatitis (AD) in adult patients .
Prolonged ingestion of L. acidophilus significantly decreased eczema area and severity index in patients with adult atopic dermatitis [542, 543]. The probiotic also suppressed scratching behavior .
Topical administration of an S. thermophilus-containing cream to patients with atopic dermatitis increased ceramide levels and improved the signs and symptoms of atopic dermatitis (i.e. erythema, scaling, pruritus) .
See individual probiotic posts for more information and animal studies.
33) Alleviate Lactose Intolerance
L. delbrueckii ssp. bulgaricus and S. thermophilus improve lactose digestion in the gastrointestinal tract and reduces symptoms of lactose intolerance .
34) May be Beneficial in Histamine Intolerance
Note that some probiotics can produce/increase biogenic amines (see Safety section).
35) Can Decrease Oxalate
L. gasseri degrades oxalate in laboratory experiments and may be beneficial in managing oxalate kidney stone disease .
A mixture of L. casei and B. breve possess a variable lowering effect upon urinary oxalate excretion that may be dependent on dietary oxalate intake .
B. animalis ssp. lactis possesses the oxc gene, encoding oxalyl-coenzyme A (CoA) decarboxylase, a key enzyme in oxalate degradation . B. animalis ssp. lactis significantly decreased urinary oxalate excretion in mice with hyperoxaluria by degrading dietary oxalate thus limiting its absorption across the intestine .
36) Beneficial for the Skin
Probiotics can restore acidic skin pH, alleviate oxidative stress, attenuate photoaging, improve skin barrier function, and enhance hair quality .
Topical application of probiotic bacteria has a direct effect at the site of application by enhancing the skin natural defense barriers. Additionally, probiotics, as well as resident bacteria, can produce antimicrobial peptides that benefit skin immune responses and eliminate pathogens .
Try: L. plantarum, B. breve
In clinical trials, L. plantarum significantly increased the skin water content in the face and hands. Volunteers in the probiotic group had a significant reduction in wrinkle depth at week 12, and skin gloss was also significantly improved by week 12. Skin elasticity in the probiotic group improved by 13.17% after 4 weeks and by 21.73% after 12 weeks .
L. paracasei contributes to the reinforcement of skin barrier function, inhibits water loss, decreases skin sensitivity and modulates the skin immune system leading to the preservation of skin homeostasis .
L. paracasei decreases skin sensitivity and increases barrier function recovery (water retention) in women .
L. johnsonii significantly inhibited the development of UVA-induced skin lesions in clinical studies .
B. longum extract, when applied to the skin, was able to improve inflammation parameters, decrease skin sensitivity, increase skin resistance against physical and chemical aggression, and decrease skin dryness in volunteers with sensitive skin .
L. lactis increased sebum content, thereby potentially reinforcing the skin barrier in healthy young women . L. lactis maintained skin hydration and improved subjective skin elasticity in middle-aged Japanese women .
Ceramides play an essential role in the barrier and water-holding functions of healthy skin. A significant increase in skin ceramide levels was observed in healthy subjects after treatment with a cream containing a preparation of S. thermophilus .
Topical treatment with an S. thermophilus-containing cream increased ceramide levels and increased hydration in the skin of healthy elderly women .
B. longum exerts photoprotective effects on the skin in mice .
B. bifidum decreases the amount of intracellular melanin and exhibits antioxidant properties in mice, and may be beneficial as a skin-whitening ingredient in various skin hyperpigmentation disorders .
L. brevis increases blood flow and decreases transepidermal water loss in rats, and could be a useful substance in the treatment/prevention of skin problems, specifically chapped or dry skin .
Animal research on L. reuteri has shown potential for improving skin quality (thickness and “glow”) and creating thick, lustrous hair .
37) Beneficial in Patients Receiving Hemodialysis
Oral administration of B. longum decreases serum phosphate levels in patients receiving hemodialysis (HD) .
38) Enhance Wound Healing
L. plantarum reduced the bacterial load of infected chronic venous ulcer wound, reduces neutrophils, apoptotic and necrotic cells, and induced wound healing in both diabetics and non-diabetics .
Topical treatment with a water-insoluble glucan from S. cerevisiae enhanced venous ulcer healing in humans. In a patient who had an ulcer that would not heal for over 15 years, this treatment caused a 67.8% decrease in the area of the ulcer .
Supplementing the rat microbiome with L. reuteri in drinking water cuts wound-healing time in half compared to control animals .
39) Combat Toxins and Pollutants
Look for: L. plantarum, L. rhamnosus, L. casei
Dietary exposure to heavy metals may have detrimental effects on human and animal health, even at low concentrations. L. rhamnosus, P. freudenreichii and their combination were found to bind cadmium and lead efficiently at low concentration ranges commonly observed in foods .
Furthermore, dietary supplementation with L. rhamnosus reduced the absorption and toxicity of consumed organophosphate pesticides in Drosophila .
Treatment with L. plantarum alleviates copper toxicity, by increasing copper excretion and reducing the accumulation of copper in tissues. L. plantarum also reversed oxidative stress induced by copper exposure, recovered the ALT and AST blood levels and improved the spatial memory of mice .
L. casei decreases the cytotoxic effects of pesticides on human cells .
L. casei supplementation reduces the level of aflatoxin in blood and can improve the adverse effect on body weight and blood parameters in rats [595, 596]. A fermented milk drink containing L. casei may reduce aflatoxin toxicity in humans .
L. paracasei reduced the adverse effects of Zearalenone (ZEN), an estrogenic toxin produced by Fusarium fungi species in pre- or post-harvest cereals in mice .
Organophosphorus hydrolase (OpdB) of L. brevis is able to degrade organophosphorus pesticides .
40) Reduce MSG
Capsules containing L. brevis reduce monosodium glutamate (MSG) levels and MSG symptom complex in humans .
L. brevis inhibits the absorption of MSG from the intestine into the blood in mice .
41) May Increase Testosterone Levels
A probiotic containing L. acidophilus, B. bifidum, and L. helveticus elevates testosterone levels in rabbits .
42) May increase Oxytocin
43) Combat Fatigue
Look for: L. acidophilus and L. gasseri
L. acidophilus reverses immune dysfunction in fatigued athletes .
L. gasseri prevents the reduction in natural killer (NK) cell activity due to strenuous exercise and elevates mood from a depressed state in university-student athletes .
44) Enhance Muscle Recovery and Boost Athletic Performance
B. coagulans enhances protein absorption, and thereby indirectly improves recovery and training adaptations .
Increase in vertical jump power was noted following 8 weeks of full body workouts 4-times per week daily while ingesting B. coagulans .
Four weeks of supplementation with a multi-strain probiotic increased running time to fatigue in the heat in male runners .
L. plantarum significantly decreased body weight and increased relative muscle weight, grip strength and endurance swimming time in mice .
45) Ameliorate Arthritis
L. casei supplementation helps alleviate symptoms and improve inflammatory cytokines in women with rheumatoid arthritis .
A mix of L. acidophilus, L. casei and B. bifidum improved rheumatoid arthritis, decreased insulin levels, and improved total- and low-density lipoprotein cholesterol levels .
Adjunctive treatment with B. coagulans was safe and effective for patients suffering from rheumatoid arthritis. B. coagulans improved pain, improved self-assessed disability, reduced CRP levels, and improved the ability to walk 2 miles, reach, and participate in daily activities .
L. casei positively contributes to osteoarthritis treatment in rats, by reducing pain, inflammatory responses, and articular cartilage degradation. L. casei together with glucosamine decreased expression of various pro-inflammatory cytokines and matrix metalloproteinases, while up-regulating anti-inflammatory cytokines .
Similarly, L. casei effectively suppressed symptoms of rheumatoid arthritis in rats: paw swelling, lymphocyte infiltration, and destruction of cartilage tissues. Anti-inflammatory cytokines were increased, while pro-inflammatory cytokines were decreased [615, 616, 617].
Oral intake of skimmed milk fermented with L. delbrueckii ssp. bulgaricus markedly inhibits the development of arthritis in mice .
L. acidophilus decreases arthritis symptoms and maintains normal histology of reproductive organs in rats .
L. acidophilus showed effects comparable to the drug indomethacin, in decreasing organ damage associated with arthritis in rats. This probiotic down-regulated pro-inflammatory and up-regulated anti-inflammatory cytokines .
L. helveticus strongly alleviated symptoms of arthritis in mice .
B. coagulans significantly inhibits fibrinogen (Fn), blood amyloid A and pro-inflammatory cytokine production in arthritic rats .
46) Beneficial for Dental Health
Probiotics are beneficial for managing gingivitis or periodontitis .
L. rhamnosus reduces oral counts of Streptococcus mutans, a bacterium correlated with caries formation .
L. casei has a bactericidal effect on all analyzed species isolated from dental plaque, while the mixed culture of L. acidophilus and B. animalis has only a bacteriostatic effect .
S. thermophilus inhibits the growth of P. gingivalis and reduced the emission of volatile sulfur compounds that can cause oral malodor .
A bacteriocin produced by L. paracasei inhibits P. gingivalis associated with periodontal disease .
Long-term consumption of L. rhamnosus containing milk reduces caries development in children .
Heat-killed L. plantarum can decrease the depth of periodontal pockets in patients undergoing supportive periodontal therapy .
Oral administration of L. casei reduced the number of pathogenic (periodontopathic) bacteria in healthy volunteers with mild to moderate gum inflammation (periodontitis) .
L. salivarius beneficially changed the bacterial population of gum plaque in volunteers .
L. salivarius increases resistance to caries risk factors in volunteers .
Oral administration of L. salivarius improved bad breath, showed beneficial effects on bleeding on probing from the periodontal pocket, and inhibited the reproduction of “bad” bacteria [629, 630, 631, 632].
L. brevis improves pH, significantly reduces salivary mutans streptococci and bleeding on probing in high caries risk schoolchildren .
L. brevis has anti-inflammatory effects and can bring about the total disappearance or amelioration of clinical symptoms in patients with periodontitis .
L. brevis exerts anti-inflammatory properties by preventing nitric oxide synthesis and may delay gingivitis development in humans .
B. subtilis reduces periodontal pathogens in humans .
Oral L. reuteri containing tablets significantly reduced inflammation in patients with chronic periodontitis .
L. brevis inhibits periodontal inflammation, significantly decreases bone loss and lowers the count of anaerobic bacteria in mice with periodontitis .
B. subtilis and Bacillus licheniformis supplementation provided a protective effect against bone loss in rats with periodontitis .
S. cerevisiae, as monotherapy or as an adjuvant, accelerated the tissue-repair process and ameliorated periodontitis in rats .
47) Can Improve Lung Injury and Inflammation
B. longum treatment significantly improved lung injury following infection and sepsis in mice. This probiotic also decreased lung inflammatory responses .
48) Probiotics are Beneficial in Smokers
In healthy shift workers, L. casei reduced the total number of clinical infectious diseases (CIDs) in the subgroup of smokers .
B. breve suppresses inflammatory agents in macrophages and may be useful in cigarette smoke-associated disease such as Chronic obstructive pulmonary disease (COPD) .
L. salivarius improved periodontal clinical parameters in smokers .
49) Good for the Bones
Bone is an organ that the gut has long been known to regulate through absorption of calcium, the key bone mineral .
Administration of probiotics leads to higher bone mineralization and greater bone strength in animals. The preferential bacterial genus that has shown these beneficial effects in bone is Lactobacillus .
L. helveticus increased serum calcium levels in geriatric volunteers .
L. helveticus fermented milk whey contains bioactive components that increase bone formation .
B. longum supplementation alleviated bone loss and increased bone formation parameters and bone mass density in ovariectomized rats .
50) Boost Female Fertility
L. plantarum ameliorated inflammation induced infertility in mice .
L. plantarum reinforced natural microflora and lead to a resurge of fertility in mice infected with E. coli .
51) Beneficial in Endometriosis
L. gasseri improves menstrual pain and dysmenorrhea in patients with endometriosis .
L. gasseri inhibits the growth of endometrial tissue in the abdominal cavity in mice and rats .
52) Beneficial in Pregnancy
Use of a specific set of probiotics during the first 1,500 days of life can lower the risk of infections and inflammatory events in infants .
L. rhamnosus affects the immune regulation and immune responses favorably in mothers and offspring. In addition, some of the beneficial effects of prenatal L. rhamnosus supplementation extend into postnatal life of the offspring, suggesting a possible immune programming effect of L. rhamnosus .
The intake of milk fermented with L. casei during the lactation period modestly contributes to the modulation of the mother’s immunological response after delivery and decreases the incidence of gastrointestinal episodes in the breastfed child .
B. animalis spp. lactis supplementation in pregnancy has the potential to influence fetal immune parameters as well as immunomodulatory factors in breast milk .
B. animalis ssp. lactis mitigates the negative immune-related effects of not breastfeeding and cesarean delivery by augmenting the immune response, evidenced by increased anti-rotavirus- and anti-poliovirus-specific IgA .
Oral administration of L. salivarius during late pregnancy appears to be an efficient method to prevent breast infection in pregnant women .
L. acidophilus, L. casei and B. bifidum significantly decreased fasting plasma glucose, insulin levels, and insulin resistance and increased insulin sensitivity in pregnant women with gestational diabetes mellitus. In addition, significant decreases in serum triglycerides and VLDL cholesterol concentrations were recorded .
B. coagulans containing symbiotic decreased blood insulin levels, HOMA-IR, and HOMA-B in pregnant women .
Preeclampsia is associated with an impaired antioxidant defense that results in maternofetal complications. S. cerevisiae scavenged nitric oxide radicals and decreased oxidative stress in red blood cells and alleviated stress status in the preeclamptic fetus .
Continuous consumption of fermented milk containing L. casei alleviates constipation-related symptoms, provides satisfactory bowel habit and results in earlier recovery from hemorrhoids in women after childbirth .
L. fermentum alleviates pain and reduces the load of Staphylococcus in the breastmilk of women suffering from painful breastfeeding .
53) Have a Positive Effect on Infant Growth
B. breve significantly decreased aspirated air volume and improved weight gain in very low birth weight infants .
L. plantarum strain maintained the growth of infant mice during chronic undernutrition .
54) Improve Feeding Tolerance
Preterm infants supplemented with B. coagulans had improved feeding tolerance .
Prophylactic supplementation of S. boulardii improved weight gain and feeding tolerance and had no adverse effects in preterm infants >30 weeks old .
Orally administered S. boulardii reduced feeding intolerance and clinical sepsis in very-low-birth-weight (VLBW) infants .
55) Are Beneficial in Aging
Levels of Bifidobacteria decrease as we age .
B. animalis spp. lactis can enhance natural immunity in healthy elderly subjects . B. animalis spp. lactis increases leukocyte phagocytic and NK cell tumor-cell-killing activity in the elderly and increases the proportions of total, helper (CD4(+)), and activated (CD25(+)) T lymphocytes and natural killer cells [679, 680, 681].
B. longum stimulates the immune functions in the elderly .
B. bifidum and L. acidophilus positively modulate of the immunological and inflammatory response in elderly subjects .
L. delbrueckii ssp. bulgaricus could favor the maintenance of an adequate immune response in the elderly, mainly by slowing the aging of the T-cell subpopulations and increasing the number of immature T cells which are potential responders to new antigens .
Feeding of probiotic bacteria (L. reuteri) to aged mice induced integumentary changes mimicking peak health and reproductive fitness characteristic of much younger animals .
L. lactis along with L. acidophilus or combined with L. acidophilus and B. bifidum reversed age-related decline in immune functions and improve lymphocyte functions in aging mice .
Dahi containing L. acidophilus was effective in reversing age-related immune function decline in mice , where this probiotic also combats oxidative stress and molecular alterations associated with aging .
L. fermentum alleviates immunosenescence by enhancing antioxidant enzyme activities and was shown to reduce E. coli infection in aging mice .
L. johnsonii helps recover nutritional status and systemic immune responses in aged mice .
Long-term oral intake of L. lactis suppressed the reduction of bone density and body weight in senescence-accelerated mice .
B. bifidum delays immunosenescence in mice by enhancing the anti-oxidation activity in thymus and spleen, and by improving the immune function .
Intake of heat-killed L. lactis altered the intestinal flora, affected plasma metabolite levels, including fatty acid levels, and slowed down age-related hearing loss in mice, by inhibiting the loss of neurons and hair cells in mouse inner ear .
56) Can Alleviate Pain
Oral administration of L. acidophilus induces the expression of mu-opioid and cannabinoid receptors in intestinal epithelial cells and mediates analgesic functions in the gut similar to the effects of morphine .
B. coagulans + fructooligosaccharide (FOS) decreased abdominal pain duration and frequency in children with GI disorders .
B. coagulans synbiotic seems to be effective in the treatment of childhood functional abdominal pain .
B. coagulans significantly improved abdominal pain and the quality of life in adults with postprandial intestinal gas-related symptoms and no GI diagnoses .
L. reuteri ingestion impacts the nerves in such a way that it may slow gut motility (improving cases of diarrhea) and decrease pain perception .
57) Can be Beneficial After Surgery
A symbiotic containing L. acidophilus, L. rhamnosus, L. casei, B. bifidum, and fructooligosaccharides reduced postoperative mortality, lowered the incidence of postoperative infections, shortened the duration of antibiotic therapy, and decreased noninfectious complications, decreasing overall hospital stay in patients undergoing surgery for periampullary neoplasms .
58) Combat Candida
Clinical trials have shown the beneficial effects of probiotics in reducing oral, vaginal, and enteric colonization by Candida. Probiotics alleviate clinical signs and symptoms, and, in some cases, reduce the incidence of invasive fungal infection in critically ill patients .
In patients with vulvovaginal candidiasis, L. plantarum reduces vaginal discomfort after conventional treatment, improves vaginal bacteria content and the vaginal pH value .
In a clinical trial, L. plantarum use was associated with a three-fold reduced risk of recurrence of vulvovaginal candidiasis .
L. fermentum and L. acidophilus maintain the vaginal biofilm and hinder the persistence of vulvovaginal infection caused by Candida in women .
L. rhamnosus has been shown to prevent enteric colonization by Candida species in preterm neonates .
L. reuteri lozenges were shown to fight oral candida in a study of older patients .
S. cerevisiae, when administered orally, colonizes the bowel of healthy volunteers and can potentially replace resident Candida species .
See individual probiotic posts for more information and animal studies.
59) May Protect from Heat Stress
Exposure to extreme heat can cause illnesses and injuries. B. subtilis was effective in the prevention of complications related to heat stress in rats. When rats were subjected to heat stress (45°C), adverse effects such as morphological changes in the intestine, bacterial translocation, elevated levels of LPS and IL-10, and increased vesiculation of erythrocytes were observed only in animals not protected with B. subtilis .
60) May Be Beneficial In HIV Infected Patients
Treatment with S. boulardii decreases microbial translocation (LBP) and inflammation parameters in HIV-1-infected patients with long-term virologic suppression .
61) Combat and Prevent Cancer
Probiotic bacteria have shown anti-tumor activities and can reduce the risk of cancer. They are effective in delaying cancer onset and progression as well as in controlling cell growth mechanisms .
Studies in Humans:
L. casei administration significantly reduced the recurrence rate of bladder cancer and colorectal cancer in cancer patients .
L. rhamnosus has been shown to decrease the incidence of colon tumors and precancerous lesions in experimental animals as well as in human cells , and possess antitumor effects in animal models of bladder cancer .
L. casei decreased cell migration and invasion of colorectal cancer cells [732, 733], inhibited human and mouse colon cancer cell growth, and resulted in an 80% reduction in tumor volume of treated mice .
L. casei delayed and suppressed tumor growth in mice with breast cancer, both when it was administered preventively and as a treatment. L. casei further reduced tumor vascularity and lung metastasis, and prolonged survival [735, 736, 737].
Similarly, L. casei decreased breast tumor volume and tumor vascularity in rats .
L. delbrueckii ssp. bulgaricus inhibits intestinal carcinogenesis in rats, ear-duct tumors in rats, and tracheal carcinogenesis in hamsters . This probiotic was also reported to inhibit the growth of sarcoma , leukemia, plasmacytoma, adenocarcinoma, melanosarcoma, and spontaneous tumors in mice .
L. acidophilus suppressed colon tumor incidence, tumor multiplicity, and reduced tumor size in mice .
L. acidophilus reduced tumor volume growth by 50.3 %, reduced the severity of colonic carcinogenesis, and enhanced cancer cell death in mice .
Dietary B. longum significantly inhibited colon and liver and small intestinal tumors in male rats. In female rats, dietary supplementation also suppressed mammary carcinogenesis .
B. animalis ssp. lactis decreased the mean number and size of tumors in mice with colitis-associated cancer .
Furthermore, in mice, co-treatment with C. butyricum and B. subtilis inhibits the development of colorectal cancer .
An antitumor molecule derived from L. brevis inhibits colon adenocarcinoma cell viability and the growth of these cells in mice .
Mice with fibrosarcoma, treated by S. thermophilus were protected against this tumor when re-challenged. Additionally, spleen T-lymphocytes from cured animals could effectively transfer the antitumor activity to recipients transplanted with the tumor .
P. freudenreichii is able to kill colon cancer cells in rats .
62) Could Reduce Toxins and Carcinogens in the Gut
Most probiotics are safe. However, care should be taken when administering probiotics to severely ill or immunocompromised patients. There have been rare incidents of sepsis, endocarditis, and liver abscess during the use of Lactobacilli; additionally, fungemia has been reported with the use of S. boulardii, primarily in patients with severe comorbidities .
The most common side effects of probiotics are constipation, flatulence, hiccups, nausea, infection, and rash .
Some probiotic bacteria can produce biogenic amines: L. brevis and L. lactis can produce tyramine and putrescine [765, 766, 767]. S. thermophilus can produce low amounts of histamine and tyramine . L. reuteri is able to produce histamine [769, 770].
In rare cases S. cerevisiae may induce allergic responses .
B. bifidum cell-surface biopolymers (BPs) can interact selectively with human serum thyroid peroxidase (TPO) and thyroglobulin (Tg) autoantibodies (anti-TPO and anti-Tg, respectively). There is a possibility that Bifidobacteria play a role in the pathogenesis of autoimmune thyroid diseases (ATD) in those with a genetic predisposition to ATD .
Probiotic products can be formulated as capsules, tablets, powders (which are regulated as a dietary supplement), and a food ingredient (e.g., yogurts, kefirs) .
L. acidophilus and B. longum can survive and adhere better to the gastric mucosa than S. thermophilus and B. infantis/adolescentis/bifidum .
L. acidophilus can survive at pH ≥3 after 3h, and L. rhamnosus can survive 4h incubation at pH 2.5. The viability of several strains of Bifidobacterium was maintained for ~3h in the pH range of 1.5 – 3.0. On the other hand, L. delbrueckii and S. thermophilus do not readily survive stomach acidity .
To overcome the inability of some probiotics to survive, microencapsulated or coated probiotic strains have been developed .
Furthermore, even though some viable probiotic strains do not survive gastric transit, their dead forms remain beneficial. These nonviable probiotics are now known as ‘para probiotics’ or ‘ghost probiotics’. Non-viable probiotics can ameliorate the anti-inflammatory response in rats with colitis, protect against Candida, or exert antiproliferative and proapoptotic effects on cancer cells .
Each probiotic species comes in many different strains. Some of the properties of each species may be strain-specific or vary between strains. You can find the information about each strain in the reference.
For technical information, check individual probiotic chapters:
- B. animalis (B. lactis)
- B. bifidum
- B. breve
- B. coagulans (L. sporogenes)
- B longum
- B. subtilis
- C. butyricum
- L. acidophilus
- L. brevis
- L. casei
- L. crispatus
- L. delbrueckii (L. bulgaricus, L. lactis)
- L. fermentum
- L. gasseri
- L. helveticus
- L. johnsonii
- L. lactis
- L. paracasei
- L. plantarum
- L. reuteri
- L. rhamnosus
- L. salivarius
- P. freudenreichii
- S. boulardii
- S. cerevisiae
- S. thermophilus
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