The probiotic L. brevis has many potential benefits to dental health, immunity, and the gut, while new research suggests it could also help with sleep and inflammation. Learn more here.
L. brevis 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 supplementing.
L. brevis reduced the incidence of influenza in 1089 elementary school children. The improvement was especially pronounced in unvaccinated individuals .
Oral administration of live, but not heat-killed, L. brevis significantly increased IFN-α production in 60 volunteers. The intake tended to be most beneficial in subjects with initially low levels of IFN-α production .
L. brevis alleviated influenza virus infection symptoms in mice .
L. brevis enhanced cytotoxic activity of mouse splenocytes .
L. brevis exhibited antiviral activity towards herpes virus (HSV-2) and inhibits HSV-2 multiplication .
L. brevis improved oral pH, reduced salivary Streptococcus mutans, and reduced bleeding on probing in 191 high caries risk schoolchildren .
L. brevis had anti-inflammatory effects and brought about the total disappearance or amelioration of clinical symptoms in 8 healthy subjects and 21 patients with periodontitis .
L. brevis exerted oral anti-inflammatory properties, possibly by preventing nitric oxide synthesis, in 34 healthy adults .
L. brevis inhibited periodontal inflammation, significantly decreased bone loss and lowered the count of anaerobic bacteria in mice with periodontitis .
Marked enhancement of NK-cell activity and improved bowel symptoms were observed in 44 female students with constipation, who consumed pickles containing dead L. brevis cells .
L. brevis treatment decreased H. pylori colonization and reduced polyamine biosynthesis in dyspeptic 22 H. pylori patients .
Polyphosphate (polyP), an active molecule derived from L. brevis, improved inflammation and fibrosis in mice with chronic colitis .
The following purported benefits are only supported by limited, low-quality clinical studies. There is insufficient evidence to support the use of L. brevis probiotics for any of the below-listed uses. Remember to speak with a doctor before taking L. brevis probiotics, and never use them in place of something your doctor recommends or prescribes.
Daily voluntary wheel-running and sleep rhythmicity become intensified in mice when heat-killed L. brevis is added to the diet .
Oral mucositis is one of the most common, debilitating complications of cancer treatments, particularly chemotherapy and radiation. In 200 patients, 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. brevis inhibited the absorption of MSG from the intestine into the blood in mice .
No clinical evidence supports the use of L. brevis probiotics 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.
Oral administration of L. brevis significantly inhibited IgE production, swelling, and the development of atopic dermatitis in mice .
In a cell study, L. brevis inhibited fat cell production, cellular triglyceride accumulation, and GPDH activity .
L. brevis enhanced appetite in mice .
Oral administration of L. brevis ameliorated ethanol-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 .
L. brevis increased blood flow and decreases transepidermal water loss in rats, suggesting that it could be a useful substance in skin health, specifically chapped or dry skin. This has not been investigated in humans .
Organophosphorus hydrolase (OpdB) of L. brevis is able to degrade organophosphorus pesticides .
An antitumor molecule derived from L. brevis inhibited colon adenocarcinoma cell viability and the growth of these cells in mice .
The relevance of this study to human cancers is unknown, and cell studies should never be used to justify taking L. brevis or any other supplement.
In cells and animals, researchers have observed that L. brevis:
- Shifted the Th1/Th2 balance toward Th1 dominance .
- Polarized M1 macrophages to M2-like macrophages .
- Increased IgA  and inhibited IgE .
- Beneficially affected various physiological processes via the serotonin 5-HT3 receptor [34, 31].
- Decreased TNF-α [27, 15, 17, 16, 14, 30, 9].
- Increased IFN- α [2, 3], and both increased  and decreased IFN-γ .
- Decreased IL-1β [15, 17, 16, 14, 9], IL-4 , IL-6 [27, 15, 16, 9], and IL-17A .
- Increased IL-10 [16, 25].
- Both decreased  and increased IL-12 .
- Both decreased  and increased TGF-β .
- Increased adiponectin .
- Decreased iNOS[15, 16], NO, PGE2 , COX2[15, 16], MPO, FOXP3, TLR4 , PGE2, MMP , PPAR-γ, CEBP-α, aP2, LPL, LXR– α, leptin, GPDH , IRAK1, AKT, NF-κB , SREBP-1, and SREBP-2 .
- Increased HSPs and p38 MAPK .
L. brevis is considered safe for human consumption .
Probiotics should be avoided in patients with organ failure, immunocompromised status, and dysfunctional gut barrier mechanisms, where they may cause infections. To avoid any adverse effects or unexpected interactions, talk to your doctor before taking L. brevis probiotics.