Over the last few years, there's been a lot of buzz about probiotics, the so-called "good" bacteria that reside in the gut. They're believed to offer a wide range of health benefits, from a robust immune system to improved digestion.

Not long after we started hearing about probiotics, prebiotics became a thing. Prebiotics are "most soluble fibers and resistant starches" that those good gut bacteria rely on for food, says Emilie Vandenberg, a registered dietitian at the Ohio State University Wexner Medical Center in Columbus.

Even more recently, the term postbiotics began circulating in nutritional journals and health media. These are "compounds produced by the gut microbes that potentially confer a benefit," Vandenberg explains.

Also called short-chain fatty acids, "postbiotics are the byproducts produced by microbes during fermentation and can be found in fermented foods," Vandenberg says. "A similar process happens in our bodies when microbes in our guts feed on prebiotics. These byproducts of microbe metabolism include short chain fatty acids, cell components and peptides, and they can have a beneficial effect on our gut health."

Dr. Rajsree Nambudripad, integrative medicine specialist with St. Jude Medical Center in Fullerton, California, explains that postbiotics are the outcome of the digestion process in the gut, and you want to encourage them as much as possible.

"When the bacteria in your gut called probiotics, metabolize the fiber (or prebiotics) in your diet, that generates something called short-chain fatty acids, which are postbiotics."

How Postbiotics Support Health

Dr. Robert Lerrigo, associate chief of gastroenterology at Santa Clara Valley Medical Center in California, notes that research into postbiotics is just getting started. But while it's a very new field of study, it's believed that postbiotics can support health in a number of ways, including:

• Reducing inflammation.

• Promoting motility, or the movement of waste through the digestive tract.

• Boosting your metabolism.

• Increasing calcium absorption.

• Improving your immune system.

• Preventing chronic health problems such as Type 2 diabetes.

Vandenberg says some research has shown that "the gut microbiome also produces neurotransmitters that play a role in mental health including dopamine, serotonin and norepinephrine."

One postbiotic in particular, called butyrate, seems to have important gut-healing properties, Nambudripad says. "In fact, it's 'food' for the cells lining your colon, called colonocytes. Research shows that butyrate reduces inflammation in your gut lining, prevents leaky gut, promotes healthy gut motility, improves your metabolism, improves brain function and even prevents colon cancer.

Other notable postbiotics include acetate and propionate. Along with butyrate, these three postbiotics constitute about 95% of the short-chain fatty acids in the body.

Postbiotics are the end goal of boosting your intake of prebiotics and probiotics. "The most important indicator of your gut microbiome health is the postbiotics," Nambudripad says. You can measure your levels of postbiotics using a comprehensive stool test.

Not having a high enough level of postbiotics could mean there's some health issues lurking, Nambudripad says. "I have observed that patients with low postbiotics (low short-chain fatty acids and butyrate) often have problems with their weight and metabolism."

How to Get Enough Postbiotics

The theory behind boosting postbiotics is one of "skipping the middle man," Lerrigo says. In this scenario, the middle man is the gut bacteria, so it's thought that simply consuming fermented foods such as kimchi or kefir or postbiotic supplements directly may help you cut to the chase on health benefits.

You can improve your postbiotics in a few ways:

Increase Your Fiber Intake

The first is to increase the amount of fiber in your diet. "This means eating a rainbow of fruits, veggies, whole grains, nuts and seeds," Nambudripad says.

Eat More Fermented Foods

Vandenberg notes that "you can also get postbiotics from eating a variety of fermented foods such as sauerkraut, kimchi and kefir." These, along with yogurt, kombucha, tempeh and miso, are fermented foods that can be good additions to your diet.

Consume More Butyrate

Butter and ghee (clarified butter) are two good food sources of butyrate, the special postbiotic that you definitely want to be sure to get enough of, Nambudripad says.

"However, many people don't tolerate dairy products, and obviously butter should be consumed in moderation" because it's high in calories and fat. "The good news is butyrate can be taken in supplement form as well, and I often recommend this when I measure low butyrate levels on the comprehensive stool test."

Other foods that can help your body produce more butyrate include apples, almonds, rolled oats, under-ripe bananas and cooked then cooled potatoes or rice.

Take Supplements

Another way is to take a probiotic supplement that also contains a prebiotic like larch arabinogalactans (a type of fiber that ferments in the gut) to boost production of postbiotics, Nambudripad explains. "I often treat patients with low postbiotics by giving them this type of probiotic/prebiotic combination, as well as encouraging them to eat more fiber in the diet."

This approach can boost postbiotic levels, and may help you "feel significantly better," she says. "I like to call this a microbiome reboot."

Should You Supplement?

Overall, research into the role gut health plays in overall health is still quite new, Lerrigo says. "More than 80% of all gut microbiota-related scientific publications, which 'postbiotics' falls into, in the last 40 years have occurred between 2013 and 2017." While the initial findings have been exciting, "it's also important to realize that the commercialization of the gut microbiome has at times exceeded the actual science."

With those caveats, Lerrigo recommends looking to your diet first to ensure good gut health, rather than immediately reaching for a supplement until we know more definitively how it all works.

"For now, I recommend that anyone interested in promoting a healthy gut adopt a well-balanced diet that's rich in fiber, including fruits and vegetables, and devoid of artificial preservatives and sweeteners," he says.

What's more, supplementation can get expensive, and nutritional supplements aren't regulated by the U.S. Food and Drug Administration. You can't always be sure that you're getting what you pay for.

Plus, even if you do need to boost your levels of postbiotics, you might need to go through another step first, Nambudripad says. "If you're suffering from excess gas and bloating, you should first be tested for small intestine bacterial overgrowth (SIBO) since this condition should be treated first before ramping up fiber (prebiotics) in the diet, otherwise you may experience more discomfort."

Patients with SIBO don't tolerate more fiber in the diet and can actually feel worse if given a probiotic/prebiotic combination. "I like to think of SIBO treatment as phase one of gut healing, and then we work to improve the overall microbiome health and SCFA (small-chain fatty acids) to raise postbiotics in phase two of gut healing," she explains.

However, if you don't have SIBO and want to use a supplement to boost your fiber intake, Vandenberg recommends using "prebiotic supplements such as wheat dextrin, acacia powder, guar gum and psyllium," which can be used to "help increase the variety of prebiotic fiber in your diet."

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