You’ve Heard of Probiotics and Prebiotics, but What the Heck Are Postbiotics?

May 9, 2021

by Cathe Friedrich

Just when you thought you had the gut microbiome figured out, scientists introduce a new term, postbiotics. Be careful, or you might confuse postbiotics with two other terms that relate to gut health: probiotics and prebiotics.

The Ecosystem in Your Gut

If you need a refresher, probiotics are beneficial bacteria that live in your gut and make up the gut microbiome, the living ecosystem within your digestive tract. These “friendly” bacteria play a variety of roles. Research shows they affect nutrient absorption, synthesize some vitamins, like vitamin K and B-vitamins, and are important for digestive, immune, and even brain health.

In contrast, prebiotics is fermentable fiber in the food you eat. Fermentable fiber supports probiotic bacteria by supplying them with nourishment and energy. You can’t break down prebiotic fiber, but gut bacteria can, and they do it through a process called fermentation. Just when you thought you had it figured out, along comes postbiotics!

What Are Postbiotics?

Postbiotics are the compounds produced by probiotic bacteria in the gut when they consume prebiotics. Research shows these compounds have beneficial effects on human health. Postbiotics covers a lot of territory from a chemistry standpoint. Some of the substances include proteins, polysaccharides, and fatty acids.

Of the postbiotics scientists know about, some of the most beneficial are short-chain fatty acids. (SCFAs) that are healthy for your gut lining. When probiotic bacteria munch on prebiotic fiber, they release short-chain fatty acids that come into contact with your gut tissue. The best known of these are butyric acid, a 4-carbon fatty acid, and propionic acid, a fatty acid with 3 carbons.

Of the two types of short-chain fatty acids, scientists have studied butyric acid the most. Their findings? Research shows butyric acid has anti-inflammatory effects on the lining of the gut. Since inflammation drives many health problems, including gut health issues, butyric acid may be beneficial for people who have inflammatory diseases of the bowel such as Crohn’s disease and ulcerative colitis.

Plus, there’s some evidence that these short-chain fatty acids lower the risk of colon cancer. That’s important since colon cancer is on the rise in people under the age of 50 and inflammation due to obesity and a poor diet may contribute factors.

Certain foods also contain butyric acid, particularly full-fat dairy foods like butter and cheese, but it’s not clear whether food sources of butyric acid have the same effects on the lining of the gut when you get them through food. Gut bacteria deliver butyric acid directly to the gut lining for maximal health impact.

Can Postbiotics Reduce Appetite?

Short-chain fatty acids, a type of postbiotic, may have other health benefits too, including effects on appetite and food consumption. One way to address the obesity problem is to curb appetite and overeating, although obesity is a more complex issue than calories in and calories out. Some research finds that short-chain fatty acids (postbiotics) boost gut hormones that suppress appetite.

Other studies suggest that propionic acid, another short-chain fatty acid, reduces an enzyme called fatty acid synthase, that encourages the body to store fat. A few studies also show that short-chain fatty acids enhance at oxidation for greater fat loss. Therefore, postbiotics may be helpful for people who are overweight or obese by reducing appetite, reducing fat storage, and boosting fat breakdown. All good things if you’re trying to get leaner!

How Can You Get the Benefits of Postbiotics?

Since postbiotics are the by-products of gut bacteria, you can get their benefits by feeding your gut bacteria the food they crave most, fermentable fiber, also known as prebiotics. When gut bacteria consume prebiotic fiber, they produce postbiotics and your gut gets the benefits. Not all fiber is fermentable. Some examples of fermentable fiber are pectin, abundant in apples and citrus peels, beta-glucan in oats, inulin, oligofructose, and guar gum.

How can you get more of it? You can get some fermentable fiber by increasing the amount of total fiber in your diet, but some foods are standout sources of fermentable fiber, such as lentils, and beans. Beans are also an excellent source of plant-based protein, vitamins, minerals, and antioxidants. In fact, beans are one of the most nutrient-dense foods that are also rich in fermentable fiber. If they cause gas, presoak them for 12 hours and discard the soaking water before cooking them.

Don’t forget about eating foods that contain the healthy gut bacteria that produce postbiotics. You can get more probiotic bacteria by consuming more fermented foods, like yogurt with active cultures, kefir, and fermented vegetables, like sauerkraut.

Fermented vegetables are also available in some natural food markets but buy them from the refrigerated section. Canned sauerkraut has no probiotic benefits since it’s heated and processed. You can even make fermented vegetables at home. The other option is to take a probiotic supplement but talk to your doctor before doing this. Also, research the probiotics that you take carefully and make sure you’re getting a supplement that has a high enough quantity of probiotic bacteria to offer benefits. Supplements are not regulated in the same way medications are.

The Bottom Line

Now you know what postbiotics are, and how to get their potential health benefits. To simplify things, add more fermented foods and fiber-rich foods to your diet and don’t forget about beans, one of the best sources of fermentable fiber. Add more fiber to your diet, but do it slowly to give your digestive tract a chance to adjust.

References:

Delcour JA, Aman P, Courtin CM, Hamaker BR, Verbeke K. Prebiotics, Fermentable Dietary Fiber, and Health Claims. Adv Nutr. 2016;7(1):1-4. Published 2016 Jan 15. doi:10.3945/an.115.010546.
WebMD.com. “Types of Fiber and Their Health Benefits”
Front. Immunol., 11 March 2019 | https://doi.org/10.3389/fimmu.2019.00277. “Short Chain Fatty Acids (SCFAs)-Mediated Gut Epithelial and Immune Regulation and Its Relevance for Inflammatory Bowel Diseases”
Holscher HD. Dietary fiber and prebiotics and the gastrointestinal microbiota. Gut Microbes. 2017;8(2):172-184.
“Postbiotics… an emerging trend in functional foods and ….” 11 Dec. 2020, foodnavigator-usa.com/Article/2020/12/11/Postbiotics-an-emerging-trend-in-functional-foods-and-beverages-In-conversation-with-ADM.
“What are postbiotics? A G.I. doc breaks it down | Well+Good.” 16 Mar. 2020, wellandgood.com/what-are-postbiotics/.