Can Probiotics Cause Diarrhea?

Brittany Lubeck, MS, RDN
·10 min read
1

Balancing benefits and possible side effects

Medically reviewed by Elizabeth Barnes, RDN

Probiotics are good bacteria meant to cure your gut and heal your microbiome (all the living microorganisms in your body). However, probiotics may cause diarrhea and other side effects in some people.

This article will discuss probiotics, including their uses and precautions, where to find them, and how to decide whether probiotics are right for you.

What Are Probiotics?

Probiotics are live microorganisms found in certain foods and dietary supplements that are thought to provide health benefits when consumed.

Typically, probiotics are bacteria, but they may also be yeasts. Saccharomyces boulardii is a yeast often used in probiotic products. Lactobacillus and Bifidobacterium are commonly used bacteria strains.

Your body is full of bacteria and other good and potentially harmful microorganisms. The microorganisms found in probiotics are considered "good" because they help balance out the "bad" (potentially harmful) bacteria in your gut and other parts of your body.

Your gut microbiome is the community of microorganisms found in your gut. Probiotics alter your gut microbiome by increasing the number of good microorganisms and restoring balance. This leaves you with more beneficial microorganisms and fewer potentially harmful ones living in your gut.

A balanced gut microbiome is critical to your overall health.

Research shows that an unbalanced gut microbiome may increase the risk of certain health conditions. However, scientists are still trying to understand this relationship.

A poorly balanced microbiome may also make some existing health conditions worse. This is especially true for gastrointestinal disorders like inflammatory bowel disease (IBD).

<p>Alina Bitta / Getty Images</p> Older female takes daily medicine vitamin D with a glass of water

Alina Bitta / Getty Images

Older female takes daily medicine vitamin D with a glass of water

Probiotic Uses



Explainer

Supplement use should be individualized and vetted by a healthcare professional, such as a registered dietitian nutritionist (RD or RDN), pharmacist, or healthcare provider. No supplement is intended to treat, cure, or prevent disease.



Probiotics are most often used for digestive health, but they may also have other benefits and uses.

There is some evidence that probiotics may help with conditions such as:

Probiotics are also sometimes used for periodontal disease (infection of the tissue surrounding teeth) as well as certain conditions in premature infants. Recently, however, probiotic use in premature infants has led to severe and even fatal infections in some cases.

Research on these and other uses of probiotics is still emerging. Some of the research behind popular probiotic uses is outlined below.



Explainer

In the United States, the U.S. Food and Drug Administration (FDA) does not regulate supplements the way it regulates prescription drugs. That means some supplement products may not contain what the label says.

When choosing a supplement, look for third-party tested products and consult a healthcare provider, registered dietitian nutritionist (RD or RDN), or pharmacist.



Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a gastrointestinal disease made up of ulcerative colitis (UC) and Crohn's disease (CD).

IBD is chronic, and there is no cure for it for now. However, remission can be achieved with the help of certain treatments and lifestyle changes.

Probiotics are one potential treatment option for people living with IBD.

Gut dysbiosis (or the imbalance of microorganisms in the gut) is common in people with IBD. Probiotics are thought to improve the health of the gut lining and restore balance to the microbiome, the final result of which is disease remission.

Evidence suggests that probiotics containing Lactobacillus, Bifidobacterium, or certain probiotic combinations may induce remission in people with IBD. According to one review, Bifidobacterium and Lactobacillus have shown the most promise in people with UC, while combinations of probiotic strains may work best in people with CD.

That probiotics are shown to work best for IBD when used in combination with other conventional treatments is worth noting.

Irritable Bowel Syndrome

Irritable bowel syndrome (IBS) is a digestive disorder marked by symptoms such as:

It is a disorder that researchers are still trying to understand amid limited treatment options.

According to one systematic review and meta-analysis, specific probiotic strains can mitigate IBS. Combination probiotics and Bacillus strains were found to improve:

  • Overall symptoms

  • Abdominal pain

  • Bloating

  • Distension (abdominal swelling)

Lactobacillus has also been associated with improved abdominal pain in people with IBS.

In another review, Bacillus coagulans was found to be the probiotic strain with the most positive effects on IBS symptoms. Researchers also noted the apparent safety of probiotics, with few side effects reported among the studies included in the review.

Antibiotic-Associated Diarrhea

Diarrhea is a common side effect of antibiotic use. This is because antibiotics can disturb the balance of microorganisms in the microbiome.

Many healthcare professionals recommend using probiotics along with antibiotics to offset any microbiome disruption and reduce the risk of diarrhea.

Regarding scientific evidence, various human trials have shown positive effects of probiotics on the prevention of antibiotic-associated diarrhea (AAD) in both children and adults. However, many studies have been performed in inpatient settings, and researchers remain unsure of which probiotic strains are most beneficial.

Probiotics may also prove useful for people who are treated with antibiotics in an outpatient setting.

According to one review of outpatient trials, probiotics may reduce the risk of AAD by as much as 51%. Based on the included studies, Lactobacillus rhamnosus and Saccharomyces boulardii were most effective in preventing AAD.

Immunity

Your gut holds the largest portion of your immune system, which is responsible for helping your body fight off infections and illnesses.

Recent research results point to the potential role of probiotics in immune system support. However, few human trials are available in this area of research, so there is still much to learn.

One review of current evidence concluded that probiotics interact with immune cells found in the gut. It's believed that probiotics positively change gut immune cells, leading to more immune response activation. However, researchers are still trying to understand this relationship fully.

Another review reported that probiotics can play a significant role in immunity due to their ability to maintain gut microbiome health. Researchers suggested that probiotics may help to support the immunity of both healthy and diseased patients.

Overall, more research is necessary regarding the role of probiotics in immune system support in humans.

Mental Health

There is a communication network between your gut and brain, otherwise known as the gut-brain axis. This connection has been vastly researched over recent years, with some studies showing a possible cause-effect relationship between gut disorders and mental health disorders.

Various studies have found a link between poor gut health and poor mental health. Studies also suggest that probiotics may effectively treat gut and mental health. However, the use of probiotics for mental health is not yet widely accepted due to inconsistent research results.

One meta-analysis reported beneficial effects of probiotics on mild to moderate depression. Overall, studies included in the meta-analysis reported significant effects of probiotics on depression symptoms.

Researchers admit, though, that further studies in this area are necessary.

Where Can You Find Probiotics?

Probiotics can be found in foods, beverages, and dietary supplements.

The process of fermentation requires microorganisms. Thus, fermented foods, like yogurt, contain probiotic microorganisms that may benefit the gut microbiome. Sometimes, however, these probiotics may be lost during food processing.

Other foods and drinks typically contain live, active microorganisms that don't quite fit the description of probiotics but may provide benefits nevertheless. These foods and drinks include:

Dietary supplements are another source of probiotics. You can find probiotic supplements in capsules, powders, gummies, tablets, and liquids. Probiotic supplements are sold online and in various grocery and retail stores.

When choosing a probiotic supplement, read the ingredient list to learn which strains are present and whether additional ingredients, like prebiotics or other nutrients, are included.

Are Probiotics Right for You?

Probiotics may be a good option for many people but not everyone.

Including probiotic food sources in your diet is always a good idea. For example, regularly consuming probiotic-rich yogurt or Greek yogurt may benefit gut health.

For some people, regular probiotic use may help treat certain health conditions.

Research shows that various probiotic strains may positively impact the gut microbiome and, thus, treat gastrointestinal disorders like infectious diarrhea, IBD, IBS, and more.

There is also evidence that people with certain mental health disorders (such as depression) may benefit from probiotics.

However, not everyone should use probiotics.

People who are severely ill or immunocompromised (i.e., have an improperly functioning immune system) should avoid probiotics. Because of their live microorganisms, probiotics may increase the risk of infections or other illnesses in these populations.

The use of probiotics in preterm infants may also be unsafe. The FDA has recently issued a warning regarding rare instances of severe infections in preterm infants who receive probiotics. Some cases have even been fatal.

If you're interested in using probiotics or you're unsure if they're right for you, talk with a healthcare provider.

Special Considerations When Taking Probiotics

Probiotics are generally considered safe to use. However, as with most dietary supplements, there is a risk of side effects, interactions, and other causes for precaution.

Potential side effects of probiotics are reportedly mild and rare and tend to affect the gastrointestinal system. These side effects include:

Typically, these side effects should disappear after your body adjusts to the probiotics. However, if side effects persist, you may want to talk with a healthcare provider.

Rarely, probiotics may also lead to infections, producing harmful substances or antibiotic resistance.

Probiotics may be more likely to increase the risk of infection in those who are seriously ill or immunocompromised. For this reason, these populations should avoid using probiotics.

Additionally, probiotics may interact with certain medications or other supplements. According to one review, probiotics may interact with the following:

However, more research on these potential interactions is necessary. In the case of antibiotics, take probiotics at least two hours before or after antibiotics to avoid any interaction.



When to See A Healthcare Provider

If you suspect you may have a gastrointestinal disorder, seeing a healthcare provider first is essential. A healthcare provider can provide a proper diagnosis and help you decide whether probiotics will fit into your treatment plan.

You should also seek help from a healthcare provider if you experience any persistent or severe side effects when taking probiotics or are unsure if probiotics are right for you.



Summary

Probiotics are microorganisms that are thought to provide health benefits. You can find probiotics in various foods and dietary supplements.

There is evidence that probiotics may help with IBD, IBS, antibiotic-associated diarrhea, immunity, mental health, and other conditions.

When using probiotics, you may initially experience mild side effects like diarrhea, constipation, gas, bloating, or abdominal pain.

Probiotics may not be suitable for everyone. Talk with a healthcare provider before starting probiotics to ensure they're a safe option for you.

Frequently Asked Questions

Can probiotics cause diarrhea?

Although probiotics may treat diarrhea, they may also cause diarrhea.

Some studies have reported diarrhea in both children and adults who use probiotics. However, diarrhea is a rare side effect. Gas and abdominal pain are more common side effects of taking probiotics.

Are probiotics bacteria?

The majority of probiotics are bacteria, but some are yeasts.

The bacteria in probiotics are considered "good" bacteria because they can help maintain or improve the balance of your gut microbiome. Common probiotic bacteria include Lactobacillus and Bifidobacterium, but other bacteria may be present in probiotic products.

Are probiotics regulated by the FDA?

Probiotics sold as dietary supplements are mostly unregulated by the FDA. Dietary supplements don't require FDA approval, but the FDA may pull a product from the market if it deems it unsafe.

On the other hand, probiotic foods are regulated by the FDA just like any other food product.

Read the original article on Verywell Health.