What Are Postbiotics? A Comprehensive Overview

Postbiotics are bioactive compounds made when the healthy bacteria in your gut, known as probiotic bacteria, feed on various types of prebiotic food in your colon, such as fibers (3).

Although these bioactive compounds are considered the waste products of probiotic bacteria, they offer various health benefits to your body.

This is because many of the health benefits linked with prebiotics and probiotics actually come from the production of postbiotics.

There are various types of postbiotics (3):

• short-chain fatty acids
• lipopolysaccharides
• exopolysaccharides
• enzymes
• cell wall fragments
• bacterial lysates (a mixture made from bacterial components)
• cell-free supernatants (a mixture of compounds produced by bacteria and yeast)
• various other metabolites such as vitamins and amino acids

Postbiotic supplements are not as widely available yet because they’re relatively new as compared with prebiotics and probiotics.

However, you can buy them at certain health food stores and online. Alternatively, you can increase the number of postbiotics in your body by eating more prebiotic foods and probiotics, since postbiotics are their end products.

Summary

Postbiotics are bioactive compounds made when the healthy bacteria in your gut ferment fiber. There are various types of postbiotics, and they offer health benefits similar to those of probiotics.

Although the concept of postbiotics is fairly new, they’ve been around for a long time and have been linked to several health benefits.

May help boost your immune system

Postbiotics have properties that may help strengthen your immune system.

For example, postbiotics like butyrate, a short-chain fatty acid, can stimulate the production of regulatory T cells in your intestine. Those cells help control the magnitude of your body’s immune response (3).

Other postbiotics, such as cell wall fragments and supernatant from healthy bacteria, can increase the production of anti-inflammatory chemical messengers called cytokines that help reduce inflammation and promote immune responses (3).

Studies in adults have found that postbiotics may help strengthen the immune system and protect against infections like the common cold.

One 12-week study in 80 healthy older adults found that daily postbiotic supplementation lowered their risk of a respiratory infection and improved their ability to produce antibodies that help defend the body against harmful bacteria and toxins (4).

In another 20-week study, 300 older adults were given either a placebo, a low dose postbiotic, or a high dose postbiotic supplement daily to protect against the common cold.

By the end of the study, significantly fewer people in the low dose and high dose postbiotic groups developed the common cold than in the placebo group (5).

May help reduce digestive symptoms

Inflammatory bowel disease (IBD) affects more than 1 million people in the United States.

Research suggests that postbiotics, such as short-chain fatty acids, may help improve symptoms for people with mild to moderate ulcerative colitis or Crohn’s disease — two types of IBD.

People with IBD tend to produce fewer short-chain fatty acids such as butyrate in their gut, which plays a role in regulating immunity and inflammation in the digestive tract. For example, butyrate plays a role in activating the immune cells that help reduce inflammation (6).

A small study in 13 people with mild to moderate Crohn’s disease found that taking 4 grams of butyrate daily for 8 weeks resulted in clinical improvements and remission in 53% of participants (7).

Several older studies, mostly from the 1990s, on postbiotics and IBD suggest that short-chain fatty acids like butyrate may improve symptoms of ulcerative colitis (8, 9, 10, 11).

May help prevent and treat diarrhea

Research suggests postbiotics may help prevent and treat diarrhea.

For example, a review of seven studies in 1,740 children found that supplementing with postbiotics significantly reduced the duration of diarrhea and was more effective than placebo treatments at preventing diarrhea, pharyngitis, and laryngitis (12).

Similarly, a review of 23 studies in 3,938 children found that supplementing with postbiotics was significantly more effective than a placebo at preventing antibiotic-associated diarrhea (13).

In a small 2003 study, 137 adults with chronic diarrhea were treated with either a postbiotic supplement or a probiotic supplement for 4 weeks. By the end of the study, the postbiotic supplement was shown to be more effective at treating diarrhea than the probiotic (14).

Further, a 4-week study in 297 adults with irritable bowel syndrome (IBS) found that supplementing with a postbiotic significantly reduced bowel motion frequency, bloating, and pain and improved their overall quality of life (15).

Other potential benefits

Postbiotics have been associated with several other emerging health benefits, but more research is needed to determine the extent of these effects:

• May help with allergies. A study in 34 adults with atopic dermatitis (eczema) found that supplementing with a postbiotic for 8–12 weeks significantly reduced the severity of the condition. In comparison, the placebo group saw no improvements (16).
• May aid weight loss. A few studies suggest that postbiotics like short-chain fatty acids may aid weight loss by suppressing hunger signals (17, 18, 19).
• May help lower the risk of heart disease. In animal studies, butyrate seems to help lower blood pressure and suppress genes that play a role in cholesterol production (20, 21).
• May help manage blood sugar levels. Studies suggest butyrate may help manage blood sugar levels (22, 23).
• May have anti-tumor properties. Some test-tube and animal studies suggest postbiotics may have qualities that help suppress the growth and spread of some cancer cells, including colon and stomach cancer cells (24, 25, 26).
• May be better tolerated than probiotics. When you consume probiotics, you increase the number of beneficial bacteria in your body. However, some people may not tolerate probiotics well, so postbiotics may be a more suitable alternative (27).

Summary

Postbiotics have been linked to various health benefits such as aiding immunity, preventing or treating diarrhea, reducing symptoms of irritable bowel diseases, reducing the severity of certain allergies, aiding weight loss, and more.

In general, postbiotics are considered safe and well-tolerated in healthy people.

If you’re taking a probiotic supplement to increase your production of postbiotics, you may experience digestive side effects such as gas, bloating, and mild stomach discomfort. These symptoms tend to disappear once your body adjusts (28).

However, certain groups of people should avoid increasing their level of postbiotics through eating probiotic-rich foods.

These groups tend to have weaker or compromised immune systems and may therefore be at an increased risk of an adverse reaction (29):

• people who have recently had surgery
• people who have structural heart disorders
• people with digestive tract disorders
• pregnant people
• children

As with any dietary supplement, it’s important to speak with a healthcare professional before taking a postbiotic supplement, especially if you have any underlying health conditions or are taking any medication.

Summary

In general, postbiotics are safe and well-tolerated. However, due to potential health concerns, certain groups of people may want to avoid increasing their production of postbiotics through eating probiotic foods.

Postbiotics aren’t as widely available as prebiotics and probiotics.

However, you can buy them from select health food stores and online. In some cases, rather than being labeled “postbiotics,” they may have another name like sodium butyrate, calcium butyrate, or dried yeast fermentate.

Because postbiotics are made from fermentation by healthy bacteria in your gut, you can naturally increase your production of postbiotics by eating prebiotic- and probiotic-rich foods.

By increasing your intake of prebiotic and probiotic foods in order to create more postbiotics, you’ll get the added health benefits associated with pre- and probiotics.

Sources of prebiotics

Prebiotics are generally found in high fiber foods such as whole grains and vegetables. The following foods are some good sources:

• chicory root
• garlic
• onions
• leeks
• asparagus
• barley
• oats
• flaxseed
• seaweed

Sources of probiotics

Probiotics are generally found in fermented foods and beverages such as:

• yogurt with live cultures
• kefir
• sauerkraut
• kimchi
• miso
• tempeh
• kombucha

Summary

Postbiotic supplements aren’t widely available but can be found in some health food stores and online. They may be listed under an alternative name. You can naturally increase your postbiotic production by eating more prebiotic and probiotic foods.

Postbiotics are bioactive compounds made when the friendly bacteria in your gut (probiotic bacteria) digest and break down fibers (prebiotics).

Although postbiotics are technically considered waste products, they offer various health benefits, similar to probiotics.

Postbiotics may support your immune system, help prevent or treat diarrhea, reduce symptoms associated with irritable bowel diseases, and even reduce the severity of certain allergies.

Postbiotics are generally safe and well-tolerated and can be purchased from some health food stores and online. Alternatively, you can naturally increase your body’s production of postbiotics by consuming more prebiotics and probiotics.