What's the Difference Between Probiotics and Prebiotics?

A healthy gut requires both probiotics and prebiotics. Here's what you need to know about each.

April 26, 2022

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Photo by: alvarez/Getty Images

alvarez/Getty Images

You’ve probably heard if you get your gut healthy and work on your microbiome, then you will have achieved the “holy grail” of health. For many, the perceived way to do this is through a probiotic, and sometimes prebiotic, supplement regimen. Nearly four million adults in the US used probiotics or prebiotic supplements in 2015 which was a fourfold increase from 2007, according to the American Gastroenterological Association. Probiotics are the one of the most often-purchased supplements by consumers, and despite the nutrition supplement industry slowing down in 2014, probiotics as a category grew to 14.2%.

Let’s go through some basic definitions to understand what the difference is between a probiotic and a prebiotic, where you can get them, how you should ingest them and whether you actually need them or not.

What Are Probiotics?

Probiotics are defined by the World Health Organization as “live microorganisms, which when consumed in adequate amounts confer health benefits to the host.” Simple enough right? It’s believed that the use of probiotics can increase microbial diversity by improving the balance of organisms within the GI tract and reducing the risk of colonization by pathogenic bacteria.

Benefits of Probiotics

Probiotics compete with potentially pathogenic microbes along the GI tract, and in theory win out in that environment keeping you healthy. They may have anti-inflammatory properties, help with immunity and modify GI transit (think less constipation or diarrhea if that is an issue for you). Probiotics may help treat a variety of issues including IBS, IBD, GI infections, constipation and lactose intolerance. They may also be recommended to be taken with or after certain antibiotic regimens.

The effects of probiotics are being studied in the following areas:

  • Mastitis
  • Endometriosis
  • Prevention of gestational DM
  • Prevention of postpartum obesity
  • Prevention and treatment of atopic eczema
  • Anxiety and depression
  • Hypercholesterolemia
  • GERD
  • Prevention of UTIs

What to Know Before Taking Probiotics

Probiotic strains are not always specified on packaging, and in order to get the maximum benefit you have to take the one that targets the symptoms that you have. Dosage varies by strain, most promising research indicates that >10^9 CFU has yielded the best results. CFUs should also be guaranteed until the expiration date. When it comes to storing probiotics, make sure to note on the label whether the product needs regfrigeration or not.

Foods that Contain Probiotics

  • Yogurt
  • Kefir
  • Sauerkraut
  • Tempeh
  • Kimchi
  • Miso
  • Pickles
  • Bananas
  • Grapefruit

What Are Prebiotics?

Prebiotics are a type of non-digestible fiber that promote the growth and activity of beneficial microorganisms in our gut. They are found naturally in foods, but are also found in dietary supplements, often in combination with probiotics. Prebiotics cannot be broken down by your body’s enzymes and therefore remain intact in the digestive system, ultimately serving as fuel for our microbiome. In essence, prebiotics are like food for probiotics. By selectively altering the diversity and activity of our microflora, prebiotics have an indirect benefit to our health.

Benefits of Prebiotics

Prebiotics have been found to decrease inflammation in the gastrointestinal (GI) tract, improve IBS symptoms, alleviate constipation, and decrease the incidence, duration, and recurrence of traveler’s diarrhea. Metabolites of prebiotics called short chain fatty acids serve as fuel for the muscles of the GI tract and have been shown to decrease the risk of GI conditions such as ulcerative colitis. Studies have also found that prebiotics improve lactose digestion and increase the absorption of calcium, which supports bone health. Prebiotics may also have immune-modulating effects that may decrease the risk of eczema and allergies. We need more research to confirm the exact health benefits of prebiotics, but the current research is promising for several health conditions, including IBS, IBD, colorectal cancer, decreased LDL and triglycerides, increased HDL, and improvements in dermatitis, memory, cognitive function and mood, and immunity.

Several emerging prebiotics are currently undergoing research for their potential antidiabetic, anticarcinogenic, antioxidant, antimicrobial, and antiobesity effects.

How to Take Prebiotics

Prebiotics improve the lifespan and efficacy of probiotics, and may therefore work best when taken combination with one another, especially for people with digestive issues. Products that contain both probiotics and prebiotics are commonly known as symbiotics.

What to Know Before Taking Prebiotics

Best practice is to not take prebiotics if you have SIBO or FODMAP intolerances as prebiotics may cause gas, bloating, and/or abdominal pain. Also many prebiotics and probiotics are sold as dietary supplements which means they are not regulated by the food and drug administration. Dietary supplement labels can make claims without FDA approval, and it is unclear if these dietary supplements are indeed “high quality” products and they may not exactly contain what the label claims.

Foods that Contain Prebiotics

  • Green bananas
  • Apples
  • Bulgar
  • Beans, legumes, soybeans
  • Raw onion
  • Raw garlic
  • Flax seeds, chia seeds
  • Jerusalem artichokes
  • Tomatoes
  • Asparagus
  • Chicory root (inulin)
  • Raw honey
  • Whole grains (e.g., wheat, barley, rye)

Bottom Line: Taking probiotics and prebiotics aren’t a one size fits all kind of thing.

When taking probiotics, it's best practice to take the strain that can best help manage your symptoms at the right dosage supported by clinical evidence. Prebiotics can definitely help, however may not be the best for certain individuals so consider how you feel when taking these supplements before committing 100%. It's important to talk with your doctor before starting a probiotic or prebiotic regimen.

Vanessa Rissetto received her MS in Marketing at NYU and completed her Dietetic Internship at Mount Sinai Hospital where she worked as a Senior Dietitian for five years. She is the co-founder of Culina Health and is certified in Adult Weight Management (Levels I & II) by the Academy of Nutrition and Dietetics, and the founder of Culina Health. Her work in private practice also includes treatment of GI disorders, bariatric surgery, weight management, PCOS, and family nutrition. She loves helping clients take an active role in their health journey, motivating them and ensuring that they always achieve success. Vanessa was named by one of the top 5 black nutritionists that will change the way you think about food by Essence magazine. Vanessa lives in Hoboken NJ with her husband, two kids and their new goldendoodle Freddie. An exercise enthusiast, she is always up for a class as long as it's after she rides her Peloton.

*This article was written and/or reviewed by an independent registered dietitian nutritionist.

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