Study Finds Fiber Supplements Convey Similar Benefits to Gut Health

Researchers studying the gut microbiome found that fiber supplements of any kind could improve gut health.

Although there are a variety of gut health-promoting fiber supplements on the market, a recent study found that regardless of the type of fiber supplement, anyone can benefit from them, though people who eat a low-fiber diet will especially benefit, according to researchers from Duke University.

“The people who responded the best had been eating the least fiber to start with,” study lead Lawrence David, associate professor of molecular genetics and microbiology at Duke University, said in a press release.

Fermentable fiber (undigestible dietary carbohydrates that some gut bacteria can digest) is an essential nutrient for a healthy body. When bugs in the gut microbiome are fed a diet high in fermentable fiber, they produced short-chain fatty acids, which protect against gut-related diseases, colorectal cancers, and obesity.

Specifically, gut microbes produce more of the short-chain fatty acid butyrate, which can improve the gut’s defenses against pathogens, lower inflammation, and create a healthier intestinal gut lining. Fiber supplements can increase short-chain fatty acid production, including acids such as butyrate.

“We’ve evolved to depend on nutrients that our microbiomes produce for us,” Zack Holmes, a co-author of two new papers on fiber, said in a press release. “But with recent shifts in diet away from fiber-rich foods, we’ve stopped feeding our microbes what they need.”

American adults only consume 20%-40% of their recommended daily fiber intake. A low-fiber diet could be the cause behind issues such as obesity, cardiovascular disease, digestive disorders, and colon cancer, according to the study authors.

David and his team noticed that many fiber supplements appeared to be interchangeable. Since every individual is different, the researchers wanted to learn whether personalizing supplements could produce better short-chain fatty acid production.

The investigators tested 3 popular fermentable fiber supplements on 28 participants—inulin, dextrin (Benefiber), and galactooligosaccharides (Bimuno). Participants randomly took 1 of the supplements for a week, then took a week off the supplement so their microbiome could return to baseline, and then took a new type of supplement for another week. This process was repeated for each of the 3 supplements.

Researchers found that the type of supplement did not matter for participants who already ate lots of fiber at the time of the study. They also displayed the least amount of change in their microbiome because they already had optimal gut microbe diversity.

Participants on an initially low-fiber diet also did not notice a difference between the supplement type and efficacy. However, these participants experience a higher production of healthful butyrate compared to the participants on an initially high-fiber diet, according to the study authors.

David’s lab, supported by the US Office of Naval Research, did a second study that explored fiber doses. According to this study, gut microbes positively changed their gene expression for digesting food in just 1 day, showing that any fiber, and more of it, is good.

The study authors said that it’s not necessary to supplement with fiber, as foods rich in fiber are a healthy addition to any diet.

“Folks who were already eating a lot of fiber, which comes from plants like beans, leafy greens, and citrus, already had very healthy microbiomes,” Holmes said in the press release.

Reference

It doesn’t matter much which fiber you choose – just get more fiber! EurkeAlert! July 29, 2022. Accessed on Aug. 1, 2022. https://www.eurekalert.org/news-releases/960356