Prebiotic supplements can compensate for low fiber intake.

Dietary fiber refers to the indigestible components of plant-based foods. A growing body of evidence indicates that eating a fiber-rich diet decreases the risks of many chronic diseases, such as coronary heart disease, stroke, hypertension, diabetes, and some types of cancer, including breast cancer and colon cancer. Most people living in the United States only get about half of the recommended amounts of fiber daily. Findings from a recent study suggest that prebiotic supplements can compensate for dietary shortcomings in fiber intake by promoting short-chain fatty acid production.

Prebiotics are food components that support the maintenance of a healthy microbiota and create an environment that is conducive to its survival. Fructo-oligosaccharides, galacto-oligosaccharides, and trans-galacto-oligosaccharides are the most common prebiotics. Their fermentation by gut microbiota produces short-chain fatty acids, including acetate, propionate, and butyrate. Many commonly consumed fruits and vegetables, such as apples, bananas, and legumes, contain prebiotics, but they are also available in dietary supplement form.

The study involved 28 healthy adults between the ages of 18 and 70 years. Each participant took one of three prebiotic supplements (inulin, wheat dextrin, or galactooligosaccharides) twice daily for one week, followed by one week off. They repeated this process with all three of the supplement products. Participants provided stool samples, completed diet surveys, and answered online surveys about their experiences with the supplements. The investigators measured short-chain fatty acid concentrations and microbial makeup in the stool samples.

They found that changes in short-chain fatty acid concentrations were person-specific and not related to which prebiotic supplement they took. Consequently, each participant’s response to the prebiotics was inversely related to their basal short-chain fatty acid concentration, which, in turn, was associated with their habitual fiber intake. Participants whose diets were low in dietary fiber experienced marked increases in butyrate production in their guts, likely due to increases in butyrate-producing microbes. However, participants whose diets were in high in dietary fiber experienced little change in the makeup of their gut microbes.

These findings suggest that people whose diets are low in dietary fiber would benefit from supplemental prebiotics to promote short-chain fatty acid production and promote gut and overall health. Learn more about prebiotics in this episode featuring Dr. Eran Elinav.

• View full publication.