Certain probiotics can improve markers of aging and damage to the skin, teeth, and bones. Which strains have been studied, and what benefits do they have? Learn more here.
Probiotics, Skin, and Bones
The skin, teeth, and bones are at particular risk of damage and decay as we age. Skin wrinkles, photoages, and breaks down; the teeth develop cavities; the bones break down faster than they can be built back up in osteoporosis. Some research now suggests that probiotics could delay or reverse several of these processes.
However, probiotics may not be right for everyone, and they should never be used in place of something recommended or prescribed by a medical professional. Talk to your doctor about whether probiotics are right for you.
Possibly Effective For
1) Skin Health
According to one study, probiotics may be able to restore acidic skin pH, alleviate oxidative stress, attenuate photoaging, improve skin barrier function, and enhance hair quality [1].
Some researchers believe that the topical application of probiotic bacteria may enhance the skin’s natural defense barriers. Additionally, probiotics, as well as resident bacteria, can produce antimicrobial peptides that benefit skin immune responses and eliminate pathogens [2].
Human Studies:
L. plantarum improved skin hydration prevented the photoaging of human skin [3, 4]. L. plantarum further increases hydration and may help to improve skin barrier function [4].
L. plantarum inhibited the degradation of collagen, promoted collagen synthesis, and decreased reactive oxygen species (ROS) production [5].
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 [6].
L. paracasei may contribute to the reinforcement of skin barrier function, inhibit water loss, decrease skin sensitivity, and modulate the skin immune system, leading to the preservation of skin homeostasis [7].
L. paracasei decreased skin sensitivity and increased barrier function recovery (water retention) in women [8].
L. johnsonii significantly inhibited the development of UVA-induced skin lesions in clinical studies [9].
Supplementation with L. rhamnosus normalized skin expression of genes involved in insulin signaling and improved the appearance of adult acne [10].
B. longum extract, when applied to the skin, appeared to improve inflammation parameters, decrease skin sensitivity, increase skin resistance against physical and chemical aggression, and decrease skin dryness in volunteers with sensitive skin [11].
B. breve and galactooligosaccharides (GOS) increased skin hydration and clearness in healthy young and adult women [12, 13].
L. lactis increased sebum content, thereby potentially reinforcing the skin barrier in healthy young women [14]. L. lactis maintained skin hydration and improved subjective skin elasticity in middle-aged Japanese women [15].
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 [16].
Topical treatment with an S. thermophilus-containing cream increased ceramide levels and increased hydration in the skin of healthy elderly women [17].
S. cerevisiae extract (SCE) is used in cosmetics to reduce oxidative stress and improve skin conditions. It enhanced skin moisture and skin microrelief in volunteers [18].
Animal Studies:
In hairless mice, L. plantarum decreased UVB-induced epidermal thickness, suppressed water loss and increased the ceramide level [19, 20].
B. longum exerted photoprotective effects on the skin in mice [21].
B. bifidum decreased the amount of intracellular melanin and exhibited antioxidant properties in mice [22].
B. breve prevented water loss, improved skin elasticity and hydration, and attenuated the damage induced by chronic UV irradiation (photoaging) in mice [23, 24, 25].
L. brevis increased blood flow and decreased transepidermal water loss in rats. Some researchers believe that it could be a useful substance in the treatment and prevention of skin problems, specifically chapped or dry skin [26].
Animal research on L. reuteri has shown potential for improving skin quality (thickness and “glow”) and promoting thick, lustrous hair [27].
2) Dental Health
Some researchers believe that probiotics may be beneficial for managing gingivitis or periodontitis [28].
L. rhamnosus reduced oral counts of Streptococcus mutans, a bacterium correlated with caries formation [29].
L. casei had bactericidal effects on all analyzed species isolated from dental plaque, while the mixed culture of L. acidophilus and B. animalis had only a bacteriostatic effect [30].
S. thermophilus inhibited the growth of P. gingivalis and reduced the emission of volatile sulfur compounds that can cause oral malodor [31].
A bacteriocin produced by L. paracasei inhibited P. gingivalis, a species strongly associated with periodontal disease [32].
Human Studies:
Long-term consumption of L. rhamnosus containing milk reduced caries development in children [29].
Heat-killed L. plantarum decreased the depth of periodontal pockets in patients undergoing supportive periodontal therapy [33].
Oral administration of L. casei reduced the number of pathogenic (periodontopathic) bacteria in healthy volunteers with mild to moderate gum inflammation (periodontitis) [34].
L. salivarius beneficially changed the bacterial population of gum plaque in volunteers [35].
L. salivarius increased resistance to caries risk factors in volunteers [36].
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 [37, 38, 39, 40].
Oral L. paracasei significantly reduced salivary S. mutans [41, 42, 43], and increased Lactobacilli in adults [43].
L. brevis improved pH, significantly reduced salivary mutans streptococci and bleeding on probing in high caries risk schoolchildren [44].
L. brevis had anti-inflammatory effects and brought about the total disappearance or amelioration of clinical symptoms in patients with periodontitis [45].
L. brevis exerted anti-inflammatory properties. possibly by preventing nitric oxide synthesis, and may delay gingivitis development in humans [46].
B. subtilis reduced periodontal pathogens in humans [47].
Oral L. reuteri containing tablets significantly reduced inflammation in patients with chronic periodontitis [48].
Animal Studies:
L. brevis inhibited periodontal inflammation, significantly decreased bone loss and lowered the count of anaerobic bacteria in mice with periodontitis [49].
B. subtilis and Bacillus licheniformis supplementation provided a protective effect against bone loss in rats with periodontitis [50].
S. cerevisiae, as monotherapy or as an adjuvant, accelerated the tissue-repair process and ameliorated periodontitis in rats [51].
Insufficient Evidence For
The following purported benefits are only supported by limited, low-quality clinical studies. There is insufficient evidence to support the use of probiotics for any of the below-listed uses. Remember to speak with a doctor before taking probiotic supplements, and never use it in place of something your doctor recommends or prescribes.
3) Bone Health
The gut helps regulate bone health through the absorption of calcium, the key bone mineral [52].
L. helveticus increased serum calcium levels in geriatric volunteers [53].
Administration of probiotics led to higher bone mineralization and greater bone strength in animals. The preferential bacterial genus that has shown these beneficial effects in bone is Lactobacillus [54].
L. helveticus fermented milk whey contains bioactive components that may increase bone formation [55].
L. helveticus-fermented milk prevented bone loss, possibly by decreasing bone turnover and increasing bone mineral density in rats [56, 57].
B. longum supplementation alleviated bone loss and increased bone formation parameters and bone mass density in ovariectomized rats [58].
Takeaway
Various probiotics have improved important markers of skin, tooth, and bone health in human trials. Significantly, these probiotic supplements delayed or even reversed markers of aging and damage in all three arenas.
Further Reading
We’ve compiled deep dives into each potential benefit of probiotics. Check them out here:
