Probiotics are often bacteria or other living organisms, like yeasts, that are usually found in foods or dietary supplements. Experts continue to study the side effects of probiotics.

Who should take probiotics?

Since there are many kinds of probiotics, talk to your doctor to find the right one for you. Researchers are still learning which probiotic should be used for which symptoms or health issues. Probiotics may supplement treatments, but do not often replace them.

According to the AGA probiotic guideline, below are some health issues for which probiotics may help

For preterm (born before 37 weeks), low birthweight (< 2500 g) infants, specific probiotics can prevent death and necrotizing enterocolitis (a bacterial infection that can hurt the wall of the bowels), lessen the number of days required to reach full feeds, and shorten the length of the hospital stay.

Certain probiotics should be considered for:

  • Prevention of C. difficile infection in adults and children who take antibiotics
  • Management of pouchitis, a complication of ulcerative colitis that has been treated surgically.

When not to use probiotics

Probiotics do not appear to be beneficial for children in North America who have acute gastroenteritis — they should not be given routinely to children who present to the emergency room due to diarrhea.

There was insufficient evidence for AGA to make recommendations regarding the use of probiotics to treat the following conditions. For these conditions, AGA suggests that patients consider stopping probiotics.

  • C. difficile infection
  • Crohn’s disease
  • Ulcerative colitis
  • IBS

Talk to your gastroenterologist to determine if there is clear benefit to the use of probiotics. The effects of probiotics are not species-specific, but strain- and combination-specific. 

Other uses

  • Keeping up a healthy mouth, gums and teeth.
  • Putting off and treating certain skin issues, like eczema (a skin rash).
  • Keeping up a healthy urinary tract and vagina.
  • Helping allergies (mainly in children).

There is not as much research about these uses as there is about the use of probiotics to help your gut health, and studies have had mixed results. Talk to a doctor to see if probiotics could help your health issue.

How long should you take a probiotic?

If your doctor has prescribed a probiotic for you, be sure to take it just as you are told to. If not, the helpful effects of probiotics could last only a short time and might go away within a few weeks. Probiotics are generally thought to be safe if you have a normal immune system, though there is not much known about using them for a long time.

How to choose a probiotic

Probiotics have been around for many years. Now, there are so many to choose from it can be hard to figure out which are right for you. Scientists and doctors say more studies are needed to figure out which probiotics are helpful and which might be a waste of money.

In general, not all probiotics are the same, and they don’t all work the same way. Each group of bacteria has different species, and each species has different strains. This is important to remember, because different strains from the same species may have different impacts on different parts of your body. For example, consider the species E. coli and the strains that come from it:  Nissle are probiotics and can help the body, while other strains (e.g., 0157:H7) are pathogens and can harm the body.

Keep in mind that probiotics are considered dietary supplements and are not FDA-regulated like medicines. They are made in different ways by different companies. How well a probiotic works may differ from brand to brand and even from batch to batch within the same brand.

Probiotics also vary in cost. Higher cost does not always mean higher quality or performance.

Side effects may vary, too. The most common are gas and bloating. These are usually mild and don’t last long. More serious side effects include allergic reactions, either to the probiotics themselves or to other ingredients in the products. In people with a weak immune system, they could possibly cause an infection.

Probiotics can be bought from your supermarket, pharmacy or health food store, as well as on the internet. Not all claims made on labels are true, so talk to a health care professional for more advice.

Here are some tips to help you choose:

  • Check the label

    For the most part, the more information on the label, the better.

    The label should tell you the probiotic’s group, species and strain, and how many of the microorganisms will still be alive on the use-by date. More number or type of bacteria does not mean they are more effective.

    Although some products guarantee how many organisms were present at the time it was manufactured, often it is less clear how many organisms are present when these products are actually taken.

  • Call the company

    Unfortunately, many labels don’t say exactly which strain is in the product; many list only the group and the species, such as Lactobacillus acidophilus or Bifidobacterium lactis.

    If you’re planning to take a probiotic for a specific condition, call the company, and find out exactly which strains it uses and what research it has done to support its health claims. You may be able to find this information on its website, as well.

  • Beware of the internet

    If you order products from the internet, make sure you know the company from which you are ordering.

    There are scammers out there who are willing to send you fake products labeled as probiotics. At best, the ingredients could be harmless, like garlic powder. At worst, they could be laced with powerful herbs, prescription medications or illegal drugs. Some companies may simply take your money and disappear.

  • Stick to well-established companies and companies you know

    The longer a company has been around, the more likely its products have been tested and studied.

    Some places that have been making products with probiotics for a while are:

    Attune Foods, Bicodex, BioGaia, Culturelle, Dannon, General Mills, Kraft, Nestle, Procter & Gamble, VSL Pharmaceuticals, Yakult.

The best tip for choosing the right probiotic is to talk to your doctor.

How to store probiotics

Remember to store your probiotic according to how it says on the package. Make sure the product has a sell-by or expiration date. Probiotics are living organisms.

Even if they are dried and dormant, like in a powder or capsule, they must be stored the right way, or they will not be helpful.

Some require refrigeration, but others do not.

They also have a shelf-life, so make sure you use them before the expiration date on the package.

Safety of probiotics

Most probiotics are thought to be safe, even for people without a diagnosed digestive health issue. Though probiotics seem to be safe for most people, talk to your doctor before starting to take them.

  • It is not known if probiotics are safe for people with weak immune systems.
  • They might not be the right thing for some seniors.
  • Some may interfere with, or interact with, medicines.
  • Your doctor will be able to help you decide if probiotics are right for you.

Kids and probiotics

  • Research about the use of probiotics in children has grown in recent years.
  • Studies have shown that probiotics may help to treat infectious diarrhea in babies and small children.
  • Researchers are still not sure if probiotics can help kids with inflammatory bowel disease (IBD).
  • Ask your child’s doctor about probiotics before giving them to your child.

The future of probiotics

Overall, more research is needed about the safety of probiotics in general. Future studies will show whether probiotics can be used to treat diseases, are safe to use for a long time, and if they are harmful in larger amounts. These studies will also provide guidance on which probiotics to use for different health issues.

Talking to your provider about probiotics

Below is important information to help guide your conversation with your health care provider about probiotics based on AGA’s interpretation of the latest probiotics research:

Talking to your health care provider about probiotics

  1. If you are a healthy individual, it is generally thought to be safe for you to take probiotics. However, researchers are not sure of the consequences of taking probiotics long-term. If you have a chronic illness, a weakened immune system, or otherwise vulnerable (for example, you are a senior), seek guidance from your health care provider on whether probiotics may be right for you. In general, probiotics should not be used without careful consideration; like with any treatment, you should think about the potential risks and benefits.
  2. Despite what you may have read, the recent research does not mean that probiotics are unsafe or useless for everyone. However, the results suggest that you may respond very differently to the same probiotic product versus someone else, depending on your diet, genetics, microbiome and other aspects of your health. Experts are trying to better understand which bacteria are best for whom and under which conditions.
  3. Probiotics currently on the market are foods or dietary supplements. To date, no probiotic products have been approved by the FDA to treat, cure or prevent specific conditions.
Now it is time to meet with a GI-expert dietitian. To get more information about this topic, find a dietitian in your area using our Find a Health Care Provider tool.

Written by

Natalie Manitius, MPH, RDN
DIGID Disorders of the Brain Gut Interaction Workgroup ©2021