Probiotics and Prebiotics: Potential Benefits, Known Risks, and More
Diet & NutritionNutrients & Supplements

Probiotics and Prebiotics: Potential Benefits, Known Risks, and More

Probiotics and Prebiotics: Potential Benefits, Known Risks, and More
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Updated on December 17, 2025
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Note: The U.S. Food and Drug Administration (FDA) does not approve supplements for safety or effectiveness. Talk to a healthcare professional about whether a supplement is the right fit for your individual health, and about any potential drug interactions or safety concerns.

You’ve probably seen food and supplement products tout “probiotics” and “prebiotics.” But what are these, and how might they improve our health?

More importantly, should you try to get more probiotics and prebiotics from foods or supplements? And what’s the best way to do it? Here’s what you need to know.

What Are Probiotics?

Probiotics are microorganisms that support the healthy fungi, bacteria, and viruses that live in our bodies.

 A well-supported microbiome can have a positive impact on our overall health.

Probiotics are found in various foods, such as yogurt and kombucha, as well as in supplements.

What Are Prebiotics?

Prebiotics support your microbiome by providing nutrients to healthy microorganisms, including probiotics.

“They’re often types of fiber found in fruits and vegetables that support a healthy digestive system,” says Vanessa King, RDN, a spokesperson for the Academy of Nutrition and Dietetics. King is based in Oahu, Hawaii, and specializes in supplements.

What Are the Potential Benefits of Taking In Probiotics and Prebiotics?

In the broadest sense, probiotics are beneficial bacteria, says M. Andrea Azcarate-Peril, PhD, a microbiologist and professor of medicine at the University of North Carolina School of Medicine in Chapel Hill, where she runs the Microbiome Core facility.

That means that these can help your body if you ingest them in recommended amounts through food or, in some cases, supplements, according to experts.

“Probiotics help the ecosystem of your gut by balancing gut bacteria and supporting the growth of beneficial microbes,” says King.

Prebiotics may also support a healthier gut, rebalancing gut bacteria linked to certain diseases.

When probiotics and prebiotics work together, they produce fatty acids that help strengthen your intestinal walls, says King. That helps prevent harmful substances from entering your body.

Here are the potential benefits of both probiotics and prebiotics, according to recent research:

May Support Gut Health Prebiotics may support a healthier gut microbiome by “feeding” healthy bacteria and producing short-chain fatty acids, potentially helping to manage obesity, gut inflammation, immunity, and mental health.

Researchers are exploring both probiotics and prebiotics as potential and promising tools to help rebalance gut bacteria linked to diseases like food allergies, inflammatory bowel disease, liver disease, heart disease, and colon cancer.

May Help Manage Certain Chronic Conditions One review from Italy, which assessed research on the health effects of prebiotics, found evidence that prebiotics play a role in improving symptoms or quality of life in people with certain conditions, such as inflammatory bowel disease (IBD), osteoporosis, diabetes, and anxiety.

Additional research from Pakistan points toward potential benefits of probiotics for helping to prevent or manage conditions like high blood pressure and high cholesterol.

Probiotics may help improve blood sugar control in people with type 2 diabetes, although more research is needed to figure out which strains, doses, and treatment lengths work best.

In children with autism, probiotics have been found to improve both behavioral symptoms (like social withdrawal and hyperactivity) and gastrointestinal issues (like diarrhea and constipation) without side effects.

May Soothe Skin Concerns Probiotics may help suppress and improve skin conditions by decreasing oxidative stress, lowering inflammatory responses, and supporting immunity through their regulation of skin health and the gut-skin connection.

May Boost Mood Probiotics may also support emotional well-being and lower negative moods, particularly in people with high stress or risk factors, after just two weeks of use.

Weight Loss Effects of Prebiotics and Probiotics

Prebiotics and probiotics may play a role in managing weight, but research is early and evolving.

In one small study from Tunisia of 45 patients with obesity, those who took prebiotic or probiotic supplements on a low-calorie diet had significant fat-mass reduction and improved muscle strength after one month compared with the diet-only control group.

And a systematic review from Spain found that probiotics (in particular, combinations of Bifidobacterium and Lactobacillus strains) may help lower body weight, body mass index (BMI), waist circumference, and body fat — even without dietary changes.

“Probiotics have modest potential to support weight loss in people who are overweight or have metabolic syndrome,” says King.

But research is still in the early stages, and more clinical trials are needed to create clear recommendations on how to best use these to support weight loss.

Forms of Probiotics and Prebiotics

Many foods naturally contain probiotics or prebiotics, and both are available in a wide variety of supplements.

Food Sources of Probiotics

Probiotics are naturally found in fermented foods and drinks, including:

However, fermented foods that have gone through additional processing — such as pasteurization, baking, or smoking — likely don’t contain living and potentially beneficial microbes.

The most common probiotic strains include:

  • Lactobacillus acidophilus
  • Lactobacillus bulgaricus
  • Lactobacillus casei
  • Lactobacillus gasseri
  • Lactobacillus plantarum
  • Bifidobacterium bifidum
  • Bifidobacterium lactis
  • Bifidobacterium longum
  • Enterococcus faecium
  • Saccharomyces boulardii

Food Sources of Prebiotics

Prebiotics are typically found in foods that contain certain types of fiber, including resistant starch (a fiber-like carbohydrate that resists digestion). These kinds of fiber feed healthy gut bacteria, promote regular bowel movements, support blood sugar balance, and help you feel full longer, says King.

Foods containing prebiotics include:

Probiotic and Prebiotic Supplements

Probiotics and prebiotics are also available as supplements. Your doctor may recommend these if you don't get enough prebiotics or probiotics in your daily diet.

Probiotics come as capsules, powders, and liquids, some of which need to be refrigerated.

 Prebiotics are available as capsules, gummies, and powders, either by themselves or combined with a probiotic.

Synbiotics, a combination of both prebiotics and probiotics, may similarly balance gut microbiota and boost immune ability, based on a recent review and separate article discussing a consensus statement from the International Scientific Association for Probiotics and Prebiotics (ISAPP).

King recommends picking supplements that clearly label the specific strains of bacteria or yeast in the product. She also notes that supplements don’t undergo the same rigorous testing as medications. To choose a quality supplement, check the label for USP, NSF, or Consumer Labs Approved. This means the product has undergone third-party testing for quality and purity.

If you and your doctor decide a supplement is right for your health needs, check out our lists of the best prebiotic and probiotic supplements, as recommended by a registered dietitian.

Should I Take Probiotic or Prebiotic Supplements?

It’s best to get probiotics and prebiotics from food, which also supplies other helpful nutrients. If you already eat a balanced, fiber-rich diet, you may not need prebiotic or probiotic supplements, says King. But certain people may benefit from supplements, under guidance from their healthcare provider.

Your doctor may recommend a probiotic supplement as a preventive measure if you have a history of infections (like urinary tract infections) or if you’ve recently had an illness or treatment that affected your microbiome.

 Taking antibiotics, for example, decreases the diversity of bacteria in your body (known as dysbiosis) and often causes diarrhea. A probiotic supplement may restore a healthy balance of microorganisms and reduce diarrhea risk.

Probiotics taken alongside conventional treatments may provide a modest benefit for those with mild-to-moderate ulcerative colitis (UC), a type of inflammatory bowel disease. More research is needed to shape official recommendations, so it’s important to talk to your doctor before adding a supplement to your UC treatment plan.

Probiotics may also improve common GI symptoms, such as gas, bloating, and constipation, but more studies are needed to find out if they’re safe and effective for older adults.

Risks of Taking Probiotic and Prebiotic Supplements

People with a milk allergy should buy supplements carefully, as some may contain dairy (although dairy-free probiotics are available).

Regardless of allergies or food intolerances, taking probiotic supplements isn’t necessary or appropriate for everyone.

“Those with weakened immune systems, short bowel syndrome, or seriously ill cancer patients with low white blood–cell counts should be cautious and only use probiotics under medical supervision,” says King.

People with bloating issues, such as small intestine bacterial overgrowth (SIBO), or digestion issues, such as irritable bowel syndrome, may also want to avoid prebiotic supplements, as the additional fiber can make symptoms worse.

The U.S. Food and Drug Administration (FDA) regulates probiotics in food and medications differently from supplements. Because supplements don’t undergo the same level of scrutiny by the FDA, it’s crucial to talk with a doctor or a registered dietitian-nutritionist before taking any probiotic or prebiotic supplements, especially if you have an underlying health condition.

The Takeaway

  • Probiotics are microorganisms that may benefit gut health and more.
  • Prebiotics serve as nutrition and support for probiotics. Prebiotics are also linked with possible health benefits, including improved immune system function and overall health.
  • Probiotics and prebiotics naturally occur in many foods. But if you don’t get enough regularly, your doctor may recommend a supplement.
  • If you’re interested in taking probiotics and prebiotics in supplement form, talk to your healthcare team — especially if you’re managing a chronic health condition or are taking medication to treat an illness — as they’re not right for everyone.
EDITORIAL SOURCES
Everyday Health follows strict sourcing guidelines to ensure the accuracy of its content, outlined in our editorial policy. We use only trustworthy sources, including peer-reviewed studies, board-certified medical experts, patients with lived experience, and information from top institutions.
Resources
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He graduated with a bachelor's in biology from the University of Wisconsin and a medical degree from the University of Minnesota Medical School. During medical school, he completed a graduate certificate in integrative therapies and healing practices through the Earl E. Bakken Center for Spirituality & Healing. He completed his three-year residency training in internal medicine at the University of California in Los Angeles on the primary care track and a two-year fellowship in integrative East-West primary care at the UCLA Health Center for East-West Medicine.

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