Probiotics

What are probiotics?

Products sold as probiotics include foods (such as yogurt), dietary supplements, and products that aren't swallowed at all, such as skin creams.

Although people often think of bacteria and other microorganisms as harmful "germs," many microorganisms help our bodies work properly.

• Bacteria normally live in our intestines, where they help digest food, fight off disease-causing germs and make vitamins. There are a lot of them. For years people claimed bacteria outnumbered our own cells 10 to 1. Turns out it's closer to 1 to 1. Still a crowd.

Many of the microorganisms in probiotic products are the same as or similar to microorganisms that naturally live in our bodies.

Will insurance pay for probiotic treatment?

Usually not. Most probiotics are sold as dietary supplements, and insurance plans rarely pay for those.

There are a few exceptions, usually when a doctor prescribes a specific product to treat a specific medical condition. Even then, your doctor will need to show it's medically necessary.

Don't be afraid to ask your doctor for help. And don't be discouraged if your request for coverage is denied. You have the right to file an appeal.

The history of probiotics

The idea behind probiotics goes back to the early 20th century. Nobel laureate Elie Metchnikoff, known as the "father of probiotics," proposed that eating beneficial microorganisms could improve people's health.

Researchers kept digging into this idea, and the term probiotics, meaning "for life," eventually came into use.

Probiotics may contain a variety of microorganisms. The most common are bacteria from groups called Lactobacillus and Bifidobacterium. Each of these two broad groups includes many types of bacteria. Other bacteria may also be used, and so may yeasts such as Saccharomyces boulardii.

Probiotics, Prebiotics, and Synbiotics

Prebiotics are not the same as probiotics. The term "prebiotics" refers to things in our diet that help good bacteria grow instead of harmful ones.

• Prebiotics are basically food for probiotics. They're mostly fibers we can't digest, but our gut bacteria love them. Taking prebiotics can help probiotics do their job better.

Prebiotics can be found in many foods we eat every day, like fruits, vegetables and whole grains.

The term "synbiotics" refers to products that contain both probiotics and prebiotics.

• Yogurt with live cultures and added fiber (such as inulin) would fall under this term. Plenty of supplements sold online combine probiotics with various fibers to serve as the prebiotic part.

How popular are probiotics?

As of 2012, about 4 million U.S. adults had used probiotics or prebiotics in the past 30 days. Among adults, they were the third most commonly used dietary supplement other than vitamins and minerals. Use quadrupled between 2007 and 2012.

Are probiotics effective?

Researchers have studied them to see whether they might help prevent or treat a variety of health problems, including:

• Digestive disorders such as diarrhea caused by infections, antibiotic-associated diarrhea, irritable bowel syndrome and inflammatory bowel disease

• Allergic disorders such as atopic dermatitis (eczema) and allergic rhinitis (hay fever)

• Tooth decay, gum disease and other oral health problems

• Colic in infants

• Liver disease

• The common cold

• Prevention of necrotizing enterocolitis in very low birth weight infants (see the FDA warning under Safety below)

There's early evidence that some probiotics help prevent diarrhea caused by infections and antibiotics, and help with irritable bowel syndrome symptoms. But more needs to be learned.

♦ It is not clear which ones help and which don't. It's also not well understood how much you would have to take to see any benefit.

Probiotics are not all alike.

• If one specific kind of Lactobacillus helps prevent an illness, that doesn't mean another kind of Lactobacillus would do the same. Or that any of the Bifidobacterium probiotics would either.

Some have shown promise in research studies, but there isn't enough evidence to back their use for most health conditions.

♦ The U.S. Food and Drug Administration (FDA) has not approved any probiotics for preventing or treating any health problem. The closest thing is two prescription treatments for a nasty gut infection called C. diff. They contain live bacteria made from donated human stool. Yes, really. They went through full clinical trials like any other drug.

♦ In 2020, the American Gastroenterological Association (AGA) came out against using probiotics for most digestive conditions. The evidence to support them for treating digestive diseases is greatly lacking.

Some experts warn that the marketing hype around probiotics has gotten way ahead of the science.

How do probiotics work?

They may have a variety of effects in the body, and different ones may work in different ways.

Probiotics might:

• Help keep a healthy community of microorganisms

• Strengthen the digestive tract's defenses against bad microorganisms, or produce substances that keep them from growing

• Help the community of microorganisms in the gut get back to normal after being knocked off balance (for example, by an antibiotic or an illness)

• Outcompete bad microorganisms

• Stimulate the immune response

Government regulation of probiotics

Government regulation in the United States is complicated. Depending on how a product is meant to be used, the FDA might regulate it as a dietary supplement, a food ingredient or a drug.

♦ Many probiotics are sold as dietary supplements, which don't need FDA approval before they hit the shelves.

• Dietary supplement labels can make claims about how the product affects the body without FDA approval. But they can't make health claims (claims that the product lowers the risk of a disease) without the FDA's okay.

If a probiotic is ever marketed as a drug to treat a specific disease or disorder, it has to clear a much higher bar. It must be proven safe and effective in clinical trials before the FDA will approve it.

Safety and side effects of probiotics

Whether they're likely to be safe for you depends on the state of your health.

• In people who are generally healthy, probiotics have a good safety record. Side effects, if any, are usually mild digestive symptoms such as gas.

• On the other hand, there have been reports linking probiotics to severe side effects, such as dangerous infections.

♦ This usually happens in people with serious underlying medical problems. Those most at risk include critically ill patients, people who've had surgery, very sick infants and people with weakened immune systems.

♦ In 2023 the FDA warned that probiotics given to premature babies in the hospital can cause dangerous, even deadly, infections. At least one baby died. No probiotic is FDA-approved for infants of any age. If someone suggests giving one to your preemie, ask a lot of questions.

Even for healthy people, there are open questions about safety. Many research studies haven't looked closely at safety, so there isn't enough information yet to answer some of those questions.

Most of what we know about safety comes from studies of Lactobacillus and Bifidobacterium. Less is known about other probiotics. Information on the long-term safety of probiotics is limited, and safety may differ from one type of probiotic to another.

More Safety Considerations

• Don't replace proven treatments with unproven products. And don't use a probiotic as an excuse to put off seeing your health care provider about a health problem.

• If you're thinking about a probiotic supplement, check with your health care provider first. This is especially important if you have health problems. Anyone with a serious underlying health condition should be watched closely while taking them.

• If you're pregnant or nursing, or thinking about giving a child a dietary supplement, it's especially important to check with your (or your child's) health care provider.

• Tell all your health care providers about any non-prescription products you use. This helps make sure your care is coordinated and safe.

Quality concerns about probiotic products

Some probiotic products have been found to contain fewer live microorganisms than the label promised. Others have been found to contain bacterial strains that weren't on the label at all.

Source: NIH, FDA