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You’re probably familiar with probiotics, live micro-organisms in certain foods and supplements that, when consumed in the right amounts, provide health benefits.
And you might know about prebiotics, fermentable carbohydrates found in asparagus and artichokes, for example, that fuel the growth of beneficial gut bacteria.
There’s a newcomer to the “biotics” family, though, that you might be unfamiliar with: postbiotics. These bioactive compounds are turning up in supplements and are expected to make their way into foods and beverages.
But you don’t need to rely on pills or fortified foods to get them. Here’s an introduction to postbiotics, plus a quick healthy gut review.
What’s the difference between probiotics and prebiotics?
When consumed in adequate amounts, probiotic microbes (such as bacteria and yeasts) make their way to the large intestine, where they inhibit the growth of disease-causing bacteria and help maintain a healthy microbiota, the collective term for the trillions of microbes that live in our gut.
Specific strains of probiotic bacteria have been shown to improve inflammatory bowel disease, constipation, bloating, urinary tract infections, eczema, depression and anxiety. Some are also being studied for their role in weight control.
Prebiotics act like fertilizers, nourishing our gut microbes. Many are non-digestible carbohydrates found in high-fibre foods that, once in the large intestine, are fermented by gut bacteria. Prebiotics can also be consumed as supplements.
These fermentable carbohydrates are associated with improved gastrointestinal function, increased calcium, magnesium and iron absorption, enhanced satiety and a lower risk of intestinal infections.
Introducing postbiotics
There’s no official definition yet, but postbiotics are bioactive compounds produced by microbes during fermentation. They can be found in fermented foods and they’re also produced in our gut when bacteria consume prebiotics.
Postbiotic substances can include short chain fatty acids, proteins and peptides (short chains of amino acids, the building blocks of protein) or parts of dead bacteria such as cell walls.
Researchers are studying postbiotics for their potential health benefits. Postbiotics are thought to reduce inflammation, enhance the immune system, maintain a strong intestinal barrier and promote bowel motility.
While it’s early stages, studies also suggest that certain postbiotics may play a role in the prevention of Type 2 diabetes, obesity, cardiovascular disease, certain cancers and immune disorders.
Because postbiotics are not live organisms, they remain stable during heat processing. This makes it possible for manufacturers to add them to baked goods, snack foods and beverages.
Jerusalem artichokes are a good source of prebiotic carbohydrates.Lee Reich/The Associated Press
What foods contain postbiotics?
Look to your diet first to get more postbiotics.
The best way to enhance your gut microbiota’s production of postbiotics is to feed it prebiotics. Good sources of prebiotic carbohydrates include asparagus, under-ripe bananas, globe artichokes, Jerusalem artichokes, jicama, whole grain rye bread, barley, leeks, onions, garlic and chicory root.
Fermented dairy products such as kefir, buttermilk and yogurt also contain prebiotic carbohydrates. So do oats, white beans, chickpeas, lentils, green peas and cashews.
Rice, potato and yams that have been cooked and cooled are sources of a prebiotic called resistant starch, as is pasta. Cooling cooked starches changes their structure, making them resistant to digestion in the small intestine. They end up in the large intestine where they’re fermented.
Phytochemicals called flavanals in cocoa powder also act as prebiotics in the gut.
You can also get postbiotics directly by consuming fermented foods and beverages.
Include a variety of fermented foods in your regular diet. Options include kefir, kombucha, kimchi, unpasteurized sauerkraut, tempeh, natto and miso. With the exception of tempeh, these foods are also a source of gut-friendly probiotic microbes.
Postbiotics are available in supplement form, often combined with probiotics and prebiotics. You can also find supplements of butyrate, a short chain fatty acid that’s produced during fermentation.
Keep in mind though that, while considered safe, postbiotic supplements may have side effects in some people.
If you have irritable bowel syndrome, postbiotic supplements that also contain prebiotics could make digestive symptoms worse. People who have a condition called small intestinal bacterial overgrowth (SIBO) should also avoid prebiotic supplements.
Leslie Beck, a Toronto-based private practice dietitian, is director of food and nutrition at Medcan. Follow her on Twitter @LeslieBeckRD