Prebiotics vs probiotics: Differences, benefits and foods

prebiotics vs probiotics - image shows a variety of probiotic foods
(Image credit: Getty Images)

Prebiotics vs probiotics: which is better for gastrointestinal health? A healthy gut plays a major role in our overall health and wellbeing, and taking prebiotics and probiotics — either in food or supplement form —is one way to support the digestive system and keep it working efficiently.

The gut microbiome (sometimes called the gut flora) consists of 100 trillion live bacterial microbes, both ‘good’ and ‘bad’, that influence nutrient absorption, our metabolism, immunity, mental health, how well we sleep and whether or not we get spots. A Harvard Medical School study found that a healthy gut could even prevent some cancers and autoimmune diseases. 

Meanwhile research from the University of Tsukuba in Japan suggested that a healthy gut could improve sleep quality. It found that gut bacteria might influence normal sleep patterns by helping create important chemical messengers in the brain, such as mood-boosting serotonin and dopamine.

Let’s take a closer look at prebiotics vs probiotics, what the differences and benefits are, the best probiotics and how they could help improve gut health.

Prebiotics vs probiotics: What’s the difference?

Probiotics are live microorganisms or ‘good’ bacteria found in foods and supplements. According to Theresa Gentile, registered dietitian and national spokesperson for the Academy of Nutrition and Dietetics, when consumed in adequate amounts, they have the ability to restore your gut microbiome and improve microbial balance.

registered dietitian Theresa gentile
Theresa Gentile, MS, RDN, CDN

Theresa Gentile, MS, RDN, CDN, is a National Spokesperson for the Academy of Nutrition and Dietetics and the coordinator of the home enteral nutrition program at Maimonides Medical Center. Her areas of expertise include cardiovascular nutrition, enteral nutrition, family nutrition, metabolism, and weight management.

Prebiotics, meanwhile, are non-digestible fiber that act as fuel for the good bacteria, and they are also found in foods and supplements.

“They are the healthy plant fibers that are a source of food for the good bacteria in your gut,” says Gentile. “Prebiotics also support the growth and activity of probiotics and help them thrive.”  

Prebiotics vs probiotics: where can you find them?

Gentille says that you should always try to obtain your nutrition first through nutrient-rich foods, as each offers unique fibers which the different microbes in your gut like to feed on. This is one of the best ways to increase your microbial biodiversity, which is crucial for a healthy gut.

Prebiotic foods include:

  • Jerusalem artichokes
  • Soy beans
  • Onions
  • Garlic
  • Asparagus
  • Leeks
  • Unripe/green bananas
  • Chicory root

woman eating a bowl of oatmeal packed with prebiotics to support gut health

(Image credit: Getty Images)

Probiotic foods include:

  • Yogurt
  • Kefir
  • Sauerkraut
  • Kimchi
  • Miso
  • Kombucha
  • Pickles

Is it better to take a prebiotic or probiotic?

It’s perfectly fine to take prebiotics and probiotics together, a practice known as microbiome therapy. You don’t need prebiotics for probiotics to work, but it might make them more effective. In fact, one 2017 review in Frontiers in Microbiology suggested that such therapies could someday be used to treat obesity, although exactly how is still being investigated.

Gentile agrees. “We really need to consume both pre- and probiotics,” she says. “Prebiotic compounds can selectively favor the probiotic organism and promote this good bacteria's growth. To provide its health effect on the microbiome, probiotics must survive the acidic environment of the stomach to be able to get to the small intestine and colonize the host. 

“Consuming prebiotics can assist the bacteria that make it to the colon to do their job and stimulate the growth of healthy bacteria.”

woman taking a handful of probiotic supplements

(Image credit: Getty Images)

And is it better to take a prebiotic or probiotic? This depends on your health needs, says Gentille. 

“Supplementing with a prebiotic would be best if you want to improve your digestive health, or have constipation,” recommends Gentile. “Supplementing with a probiotic would be best if you have been on antibiotics that have destroyed some of the beneficial bacteria in your intestines and/or have diarrhea, and it's possible that probiotics may help atopic dermatitis, allergic rhinitis, necrotizing enterocolitis, and infant colitis. 

“The strain of the probiotic is important and one probiotic should not be considered the same as another, even if they contain the same genus or strain.”

What are postbiotics?

Postbiotics are beneficial compounds made when the friendly bacteria in your gut (probiotics) digest and break down dietary fiber (prebiotics).

“Some examples are vitamin B, vitamin K, and Short-Chain Fatty Acids (SCFA). Some exert positive benefits on our gut microbiome and some prevent unhealthy things from occurring in the body,” says Gentile.

SCFAs play an important role in our digestive health by keeping the gut environment stable and nourishing the good bacteria. They also stop opportunistic bacteria from entering our intestinal ecosystem and sticking around.

This article is for informational purposes only and is not meant to offer medical advice.

Maddy Biddulph

Maddy has been a writer and editor for 25 years, and has worked for some of the UK's bestselling newspapers and women’s magazines, including Marie Claire, The Sunday Times and Women's Health. Maddy is also a fully qualified Level 3 Personal Trainer, specializing in helping busy women over 40 navigate menopause.