Lactobacillus brevis is a type of lactic acid bacteria found in milk products and in some plants as they decompose. Fermented products, such as pickles, use the bacteria. They are also used in making wine and beer. Lactobacillus brevis, often listed on labels as L. brevis, is in some brands of yogurt. It also comes in supplement form for its reported health benefits. It exists in small amounts in the human body and in breast milk.

Probiotics have attracted a lot of attention in recent years. We are still learning about how they can improve health by preventing harmful bacteria from spreading in your digestive tract. Probiotics also give the immune system a boost.

L. brevis may help treat diarrhea in children and support natural killer (NK) cell activity in older adults. NK cells are a type of pathogen-killing cells that fight off infections and stop the growth of cancer cells.

Consuming a diet that includes foods rich in probiotics, or taking a probiotic supplement, may improve gastrointestinal health and help the body battle infections. L. brevis and other similar probiotics are also linked to better mood and improved heart and gum health. L. brevis may even boost the effectiveness of antibiotics.

Winemakers use L. brevis to make certain types of red wine less tart. It can add a slight buttery flavor to the wine, but in some cases it may negatively affect the taste. Beer brewers can use L. brevis and other lactic bacteria to add a sour flavor to the beer. These bacteria can also make the beer spoil if brewers aren’t careful.

Read more: Surprising benefits of probiotics »

Current research into the safety of probiotics is mixed. A study published in the journal Clinical Infectious Diseases points to inconsistent results in clinical trials.

Supporters of probiotics say that the long history of safe use suggests that probiotics are generally safe for healthy people. They also point to positive data from certain clinical trials, as well as from some studies done on animals and in vitro (outside the body).

One older study from 2009 published in Food and Chemical Toxicology found that a strain of L. brevis was safe for human consumption. It noted that the strain came from a fermented vegetable called suguki, eaten in Japan for hundreds of years.

Critics of probiotics describe risks from human consumption, including:

  • systemic infections
  • immune system complications
  • gastrointestinal side effects

It is clear that more research is needed to determine the safety of L. brevis.

Foods containing L. brevis include:

  • yogurt
  • sauerkraut
  • pickles
  • sourdough bread

Look for the words “live and active cultures” when shopping for foods containing healthful probiotics, and be sure to check the expiration date.

Yogurt contains milk, so it may cause some gas if you are lactose intolerant. You might want to consider taking a supplement instead. You can find probiotic supplements at health food stores and in many grocery stores. Be sure to check the expiration date on any supplements. Keep L. brevis in a cool, dry environment away from sunlight.

Read more: Are pickles good for you? »

If you take L. brevis as a probiotic supplement, the adult recommended dosage is between 10 and 20 billion colony-forming units (CFU) per day. Children should take less, between 5 and 10 billion CFU per day. These are normal dosages for most probiotic supplements. Actual amounts may vary, depending on the manufacturer.

According to the Mayo Clinic, probiotics are generally thought to be safe for healthy adults to consume. Side effects are rare, but be sure to talk with your doctor before taking probiotics or any other type of supplement.

Supplements aren’t regulated by the U.S. Food and Drug Administration (FDA) in the same way that prescription medications are. Manufacturers do not have to prove that their products are effective or safe.

Be aware that supplements of any kind may contain ingredients not listed on the label. The actual amount of a particular ingredient listed may not always be accurate. The FDA’s approach to vitamins and supplements may change in the future.

Read more: Will supplements be safer after new FDA rules? »

Probiotics like L. brevis have the reputation for improving health and immunity and preventing disease. Probiotics may start to work in the digestive tract within a couple of hours of consuming them. The time frame for longer-term health benefits is harder to anticipate.

Probiotics don’t come with a guarantee to improve digestive problems or strengthen your immune system. However, these supplements are usually well tolerated.

Even if L. brevis makes a noticeable improvement in your health, it’s only a small piece of the wellness puzzle. Other factors that are important to keeping you healthy and feeling good include:

  • eating a balanced diet
  • exercising
  • getting enough sleep
  • not smoking
  • maintaining a healthy weight

After consulting with your doctor, you may want to try adding probiotics to your healthy lifestyle, at least in the short term.