Many things can throw one’s microbiome out of kilter. Not eating enough fiber or relying too much on highly processed food can starve the “good bacteria” dwelling in your gut. Frequent and sustained antibiotic use can also unintentionally kill them off.
With today’s busy schedule, many people forgo the things that maintain good gut health. “Modern lifestyles hit the microbiome at many different angles," says Christopher Damman, a gastroenterologist at the University of Washington in Seattle.
One research bright spot? The microbiome appears to be incredibly resilient. And some straightforward dietary shifts can make an almost immediate impact.
How Long Does it Take to Improve Gut Health?
With research in the gut microbiome — the thousands of microorganisms that live in our digestive system — booming over the past decade or so, scientists have explored how gut health can impact issues like inflammation, metabolism, and immune health as well as mental health and overall well-being.
In one study, researchers fed one group of people a plant-based diet and another one heavy on meat, but low on fiber. The microbiomes of both groups changed drastically within 24 hours. They also “bounced back” when the subjects reverted to their normal diet.
That’s good to know, because it demonstrates that small lifestyle lapses need not be devastating to your microbiome.
“Even though it shifts rapidly, if you go back to what you did before, it will likely revert back,” says Gail Cresci, a gut microbiome researcher at the Cleveland Clinic.
Follow-up work showed that eating a gut-friendly diet for about six months helped solidify positive changes to the gut.
Read More: 5 Things That Will Help Keep Your Microbiome Healthy
Adding Prebiotics and Probiotics to Your Diet
So, what’s the best dietary way to manage your gut? The short answer is prebiotics and probiotics.
Prebiotics come from unprocessed fiber-rich whole foods like fruits, vegetables, whole grains, nuts and legumes. Probiotics come from fermented food like kefir, sauerkraut, and kimchi.
Prebiotics are the food supply for the gut microbiota and probiotics are the good microbes. Both prebiotics and probiotics are found naturally in certain foods, or they may also be dietary supplements.
Read More: What's the Difference Between Prebiotics and Probiotics?
Metabolites in the Gut Microbiome
When we eat foods with prebiotics, we don’t initially break them down completely. That’s where the microbiome comes in. Bacteria in the gut can metabolize the fiber-rich food, and this helps support a healthy balance of good gut bacteria as well as allow the good bacteria to produce metabolites. Those metabolites come in a variety of molecules that help the body in various ways, says Cresci.
Complicating matters, different types of fiber produce different metabolites — which have various benefits to the body.
“When we start taking different fibers from different sources, the biological impacts are pretty different,” Andrew Gewirtz, a Georgia State University researcher says.
Gewirtz is now isolating various kinds of fiber to better understand the specific roles each plays. Some fibers even produce the same kinds of reactions as drugs like Ozempic.
Read More: Gut Biome Diversity Might Shape Personality, Energy Levels
Knowing the Best Form of Fiber to Take
Fiber added to a highly processed food may not act as potently as the fiber from a more natural source. The U.S. Food and Drug Administration (FDA) changed a labelling requirement years ago that no longer differentiates between, say, the fiber from a multi-grain artisanal loaf of bread and a “fiber-enhanced” brownie that also contains many additives.
Fiber supplements can also be tricky. “You're only getting just what is in the supplement and nothing else,” Carrie Daniel-MacDougall, associate professor of Epidemiology at The University of Texas MD Anderson Cancer Center, says.
A prebiotic food generally gives rise to many good metabolites, she adds. To achieve the same prebiotic benefit as, say, a cup of beans, you’d have to take a handful of different supplements.
Damman adds that he’s not completely against fiber supplements — as long as they are, indeed, a supplement, and not a replacement for naturally occurring fiber.
“I'm also a pragmatist and recognize a busy lifestyle,” Damman says. “It's better than nothing.”
Read More: 4 Science-Backed Diets to Improve Your Health
Adding Probiotics to Your Microbiome
Probiotics — in terms of how they work in the body — are pretty straightforward. You can add bacteria from fermented foods like yogurt, sauerkraut, or kimchi directly to your gut. Each food contains multiple strains of bacteria. Each kind, when fed, may produce multiple metabolites. So, as in fiber sources, a variety of probiotic food sources may be more beneficial than a single one.
Probiotic supplements should also be carefully considered, Damman says. Because the contents of such supplements are not regulated by the FDA, you may not be getting exactly what the label says.
“Independent groups have evaluated off-the-shelf probiotics,” Damman says. “And it's really surprising just how imperfect the correlations are between what the label says and what's actually in there.”
Even probiotic supplements with similar-sounding names might not be suitable, because different subspecies could have different effects. “That adds a lot of complexity to the probiotic space,” Damman says.
Read More: What to Feed Your Microbes
Researching the Benefits of Gut Health
That’s not to say there aren’t conditions or treatments that can’t be helped by specific probiotics, though. However, in those instances, it might be best to turn to a doctor or a registered dietitian.
Targeted approaches aiming at gut health are in earlier research stages. Daniel-MacDougall is looking at how boosting the microbiome helps the immune system, which, in turn could help cancer patients. Cresci is examining how nutritional approaches targeting the human gut microbiome could repair some of the cellular and immune system damage caused by alcohol. And Gewirtz has studied the impact of the microbiome on both diabetes and obesity.
However, Mingyang Song, Harvard T. H. Chan School of Public Health epidemiologist, cautions that a tailored approach to treating many diseases via the microbiome may still be a in the future.
“It’s a very appealing concept, given that the microbiome is so important to health,” he says.
But Song also says it can be hard to “tease apart” the microbiome’s contribution to specific health issues. For instance, the same kind of diet that promotes a healthy microbiome has been linked to a lower incidence of colon cancer. But he’s unsure if the microbiome is a “mediator” or just on “standby.”
That’s not to say that a healthy microbiome doesn’t contribute to overall good health. The microbiome is likely acting in concert with a variety of other processes.
Song also recommends a diet including fruits, vegetables, and whole grains. He acknowledges that requires more work than taking a supplement or single “functional” food.
“People love to have the ‘magic bullet’,” Song says. “Unfortunately, it’s not that simple.”
Read More: New Clues to Chronic Diseases Turn Up in the Gut
Article Sources
Our writers at Discovermagazine.com use peer-reviewed studies and high quality sources for our articles, and our editors review for scientific accuracy and editorial standards. Review the sources used below for this article:
Nature. Diet rapidly and reproducibly alters the human gut microbiome.
Wiley Online Library. The Gut Microbiome: A New Frontier for Alcohol Investigation.
National Library of Medicine. Fiber-Mediated Nourishment of Gut Microbiota Protects against Diet-Induced Obesity by Restoring IL-22-Mediated Colonic Health.
Gastroenterology. Influence of the Gut Microbiome, Diet, and Environment on Risk of Colorectal Cancer.
Before joining Discover Magazine, Paul Smaglik spent over 20 years as a science journalist, specializing in U.S. life science policy and global scientific career issues. He began his career in newspapers, but switched to scientific magazines. His work has appeared in publications including Science News, Science, Nature, and Scientific American.
