L. rhamnosus is among the more promising probiotics for skin health, gut health, and respiratory inflammation. It may also help with gestational diabetes and vaginal infections, and new research has introduced the possibility of even more benefits. Read on to learn more about this intriguing probiotic supplement.
Lactobacillus rhamnosus is a gram-positive lactic acid bacterium that is part of the normal gut microflora in humans. It is generally regarded as safe and has been used extensively in food products and health supplements.
Among many other health benefits, people take L. rhamnosus to balance their immune system and alleviate allergies and dermatitis.
In a laboratory setting, researchers have observed that L. rhamnosus:
- Suppressed the production of inflammatory cytokines: IL-4, IL-5, IL-6, IL-8R, IL-13, IL-17, TSLP, IL-1β and TNF-α [1, 2, 3, 4, 5, 6].
- The mechanism of proinflammatory cytokine suppression involves CD4(+) CD25(+) Foxp3(+) Treg cells [1, 7, 3].
- Elevated anti-inflammatory IL-10 [8, 2, 4].
- Elevated and decreases interferon gamma (IFN-γ) [8, 2, 3].
- Elevated IgG and IgA [8, 2].
- Decreased IgE, IgG, IgG1 [2, 9].
- Decreased IGF1 gene expression in the skin .
- Increased FOXO1 gene expression in the skin .
L. rhamnosus probiotic supplements have not been approved by the FDA for medical use and generally lack solid clinical research. Regulations set manufacturing standards for them but don’t guarantee that they’re safe or effective. Speak with your doctor before using probiotics.
In a study of 373 pregnant women, a probiotic supplement of L. rhamnosus reduced the incidence of gestational diabetes .
L. rhamnosus also 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 .
L. rhamnosus has often been selected as candidate probiotic for the prevention and treatment of gastrointestinal infections and diarrhea. It may reduce the duration of diarrhea, particularly in children. It was also shown to reduce the risk of acquiring gastrointestinal infections when administered daily in hospitalized children .
L. rhamnosus has been proven to reduce symptoms in children with functional gastrointestinal disorders .
Supplementation with L. rhamnosus reduced the incidence of antibiotic-associated diarrhea in patients treated with antibiotics from 22.4% to 12.3% .
L. rhamnosus administration was associated with significantly lower rates of and symptomatic rotavirus gastroenteritis diarrhea in hospitalized children L. rhamnosus was well tolerated, and no harms were reported in any of the trials .
L. rhamnosus promotes gastric ulcer healing in rats .
L. rhamnosus was beneficial in patients with irritable bowel syndrome .
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 RTIs and rhinovirus-induced episodes in the first 2 months .
Consumption of L. rhamnosus reduced the occurrence of respiratory illness in children attending day care centers .
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 .
Some researchers believe that administration of L. rhamnosus in early life could play a role in food allergy prevention .
It decreased the allergic response to peanuts in children .
L. rhamnosus supplementation shows good clinical and immunologic response in children with allergic rhinitis .
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 lowered the incidence of eczema in children aged 2, 4 and 7 years old .
In milk-hypersensitive adults, L. rhamnosus has been shown to reduce the immunoinflammatory response .
Consumption of L. rhamnosus-fermented milk by mothers and offspring showed a reduction in physical allergic symptoms in newborn mice .
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 .
L. rhamnosus is effective in decreasing symptoms of atopic dermatitis after 8-weeks of treatment in children aged 4-48 months .
Oral application of L. rhamnosus prevents the development of atopic dermatitis in mice by suppressing the production of inflammatory cytokines .
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. No side effects have been reported .
Researchers are currently investigating whether L. rhamnosus has other health benefits. The potential benefits in this section have produced positive results in at least one clinical trial, but these studies are small, contradictory, or otherwise limited. Talk to your doctor before supplementing with L. rhamnosus for any reason.
L. rhamnosus appeared to promote weight loss in women, reducing fat mass and circulating leptin concentrations. However, the weight loss was minor (an additional 1.8 kg compared to the placebo), and the men in the study did not benefit at all. Additional human trials will be required to clarify whether L. rhamnosus can truly promote weight loss .
In obese children with NAFLD, L. rhamnosus restored liver function .
L. rhamnosus protects against non-alcoholic fatty liver disease in mice, by increasing beneficial bacteria in the distal small intestine and attenuating liver fat accumulation and portal alanine-aminotransferase concentrations .
L. rhamnosus reduces oral counts of Streptococcus mutans, a bacterium correlated with the formation of dental caries or cavities .
L. rhamnosus activated humoral as well as cellular immune responses in mice .
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 .
Non-viable L. rhamnosus combats pneumococcal infection in malnourished immunocompromised mice .
Mice with pneumonia treated with L. rhamnosus had significantly improved survival .
L. rhamnosus can overcome the pathogenic strain Salmonella enterica .
L. rhamnosus promotes parasite (nematode) expulsion in mice .
L. rhamnosus strains exhibit antimicrobial activity against food spoilage organisms and gastrointestinal pathogens, as well as Candida and Aspergillus .
L. rhamnosus protects against influenza virus infection in mice  and beneficially modulates inflammation. Furthermore, the non-viable heat-killed L. rhamnosus is as effective as the viable strain to beneficially modulate respiratory antiviral immune response .
L. rhamnosus enhances macrophage viability of herpes (HSV-1) elimination .
Treatment of mice with L. rhamnosus significantly reduced lung viral loads and tissue injuries after infection with the respiratory syncytial virus (RSV) .
High dose of L. rhamnosus has protective effects against rotavirus infection in newborn mice .
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 the postnatal life of the offspring, suggesting a possible immune programming effect of L. rhamnosus .
It’s important to remember, however, that pregnancy is a sensitive condition, and that each person’s experience is different. If you are pregnant, talk to your doctor before using probiotics.
No clinical evidence supports the use of L. rhamnosus for any of the conditions listed in this section. Below is a summary of the existing animal and cell-based research, which should guide further investigational efforts. However, the studies listed below should not be interpreted as supportive of any health benefit.
L. rhamnosus has an anti-inflammatory effect on allergen-induced airway inflammation in mice .
Oral administration of L. rhamnosus attenuates the features of allergic asthma in mice .
L. rhamnosus beneficially regulated the balance between pro- and anti-inflammatory cytokines in the lungs of infant mice .
L. rhamnosus ameliorates inflammation by down-regulating pro-inflammatory cytokines in rats .
Dietary supplementation with L. rhamnosus reduces absorption and toxicity of consumed organophosphate pesticides in Drosophila .
L. rhamnosus administered for 28 days reduced depression in rats .
L. rhamnosus decreases anxiety-like behaviors in mice .
Both a 2- and 4-week L. rhamnosus pretreatment attenuated OCD-like behavior induction in mice .
L. rhamnosus has been shown to decrease the incidence of carcinogen-induced colon tumors and precancerous lesions in experimental animals as well as in human cells , and possess antitumor effects in animal models of bladder cancer .
The effect of L. rhamnosus probiotics on human cancer, if any, is unknown.
However, it should not be taken by immunocompromised individuals where it can lead to bacteremia [57, 58]. Use of probiotics in patients with organ failure, immunocompromised status, and dysfunctional gut barrier mechanisms can lead to infections .
L. rhamnosus is a human probiotic strain; that is, it is a natural part of the human microbiome. It was first isolated from two healthy adults, Sherwood Gorbach and Barry Goldwin, which is why it got “GG” added to its name .
As such, L. rhamnosus is not naturally found in animal- or plant-based foods. Instead, it has to be added during the fermentation process. Various foods may have added L. rhamnosus, including yogurt, cheese, and fermented legumes [61, 62].