Why — and When — You Should Include Probiotics in Your Diet

Only certain strains have been proven to make an impact on health

yogurt and blueberries

We’ve all heard of the purported health benefits of probiotics, but what exactly is it that is supposed to make these healthy little microbes good for you? Why should we consume them?

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The answer is that probiotics can enrich and replenish the helpful bacteria that live in your intestines and ultimately strengthen your immune system. But they are not a cure-all.

And it’s important to know that only certain strains of probiotics have been proven to make an impact on health. Researchers are still trying to figure out which are best for certain health problems.

Probiotics: good bacteria

Probiotics are live microorganisms that are the same or similar to microorganisms found naturally in the human body. Bacteria normally found in the body perform several jobs, including breaking down foods, helping the body to take in nutrients and preventing the take-over of bad bacteria that can cause illness.

Probiotics, which sometimes are called good bacteria, are found naturally in some foods, as well as in over-the-counter supplements in the form of pills, powder or liquids.

When consumed, probiotics travel to the intestines and colonize. They are thought to synthesize minerals and produce vitamins and enzymes that help our immune system and keep the intestines healthy.

“The bacterial strain can secrete different proteins that help to fight infection and inflammation while it’s  inside your intestine,” says Gail Cresci, PhD, RD, an expert in intestinal microbes.

Some of this good bacteria will adhere to the lining of the intestine, which is helpful because it takes away space and a food source from bad bacteria, Dr. Cresci says.

Probiotics and antibiotics

“A bacterial strain, to be considered a probiotic, needs to have some type of beneficial effect,” Dr. Cresci says. One way that probiotics can help you is to counteract the side effects of certain antibiotic treatments.

Antibiotics work by killing off bad bacteria in the gastrointestinal or urinary tracts that cause illness. Unfortunately, antibiotics also kill off the good bacteria that help to keep us healthy. Some research has shown that probiotics can help offset these issues by restoring the good bacteria, which is lost with antibiotics.

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Antibiotics also can cause gastrointestinal issues, infectious diarrhea and irritable bowel syndrome (IBS), and some research has shown that probiotics can help ease these side effects.

RELATED: How to Prevent Diarrhea When You’re Taking Antibiotics

Types of probiotics

Most probiotics fall into one of two categories:

Lactobacillus — Found in yogurt and other fermented foods, this is the most common probiotic. Lactobacillus has been found likely effective for treating and preventing  diarrhea, including infectious types such as rotaviral diarrhea in children, and may help people with traveler’s diarrhea. Some research also supports the use of certain — but not any — strains of Lactobacillus to treat colic in babies, lung infections, ulcerative colitis, irritable bowel syndrome, vaginal infections caused by bacteria and eczema.

Bifidobacterium — Also found in some dairy products such as yogurt and cheese. Some research suggests Bifidobacterium  may help ease constipation, IBS, ulcerative colitis and lung infections.

RELATED: Which Yogurt Is Right for You?

Supplements

There are concerns about the quality of some Lactobacillus supplements. Some products labeled to contain Lactobacillus acidophilus actually contain no lactobacillus acidophilus, or they contain a different strain of Lactobacillus. Other products are contaminated with unfriendly bacteria.

In addition, some probiotic supplement manufacturers say their products can help people with celiac disease better absorb nutrients. But so far, no scientific evidence supports that claim, Dr. Cresci says.

The Food and Drug Administration regulates supplements as if they are foods. As a result, probiotic supplement manufacturers don’t have to prove that their products are safe or that they work. So be discerning in your use of these supplements and evaluate the claims closely, Dr. Cresci says.

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“There are so many out there on the market, and not all of them are legitimate,”Dr. Cresci says. “In order to be considered a probiotic, a bacterial strain has to meet certain criteria and there’s a laundry list of criteria.”

In general, probiotic supplements are thought to be safe, Dr. Cresci says. But they may trigger an allergic reaction. If you experience an allergic reaction, stop taking them and see your doctor.

RELATED: The Truth About 5 Common Dietary Supplements for Your Heart

Special precautions

There is not enough reliable information about the safety of taking bifidobacteria supplements if you are pregnant or breast-feeding. If this is you, it’s best to not take these probiotics as supplements during your pregnancy, Dr. Cresci says.

There also is some concern that probiotics might grow too well in people with a weak immune system and cause infections, Dr. Cresci says. There have been rare cases of this involving Lactobacillus. If you have a weakened immune system — for example, you have HIV/AIDS or are undergoing cancer treatment — check with your healthcare provider before using probiotic supplements, Dr. Cresci says.

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