Fiber Supplements Influence Gut Microbiome in Obese Children

A new study using a prebiotic fiber was performed on children to improve their intestinal bacteria profile. A couple of teaspoons of a fiber supplement, taken daily, has produced results that have the researchers feeling optimistic about the future of this type of therapy. [ordachelr/Getty Images]

Childhood obesity has reached epidemic proportions worldwide, especially among industrialized nations like the U.S. According to the CDC, the percentage of children with obesity in the U.S. has more than tripled since the 1970s—with approximately one in five school-aged children (ages 6–19) being obese. Scientists and physicians are constantly on the lookout for the underlying mechanisms that influence obesity, while simultaneously trying to improve children's’ diets.

In recent years, investigators have uncovered the essential role that the gut microbiota plays in maintaining proper health and the onset of various disease states. Now, a team of researchers led by scientists at the University of Calgary have just published new data that shows taking a powdered fiber supplement not only alters the gut microbiome but helps children maintain a healthier weight—potentially helping to prevent many diseases caused by obesity. Findings from the study were published recently in Gastroenterology, in an article entitled “Prebiotic Reduces Body Fat and Alters Intestinal Microbiota in Children With Overweight or Obesity.”

This is the first time a study using a prebiotic fiber was performed on children to improve their intestinal bacteria profile, as a couple of teaspoons of a fiber supplement, taken daily, has produced results that have the researchers feeling optimistic about the future of this type of therapy.

“Powdered fiber, mixed in a water bottle, taken once a day is the simple change we asked the children to do, and we got what we consider some pretty exciting results—it has been fantastic,” explained senior study investigator Raylene Reimer, Ph.D., professor and researcher at the University of Calgary's faculty of kinesiology.

Children with overweight or obesity who were recruited for the study were given a prebiotic fiber, oligofructose-enriched inulin for 16 weeks; another group of children took a placebo.

“We performed a single-center, double-blind, placebo-controlled, trial of 2 separate cohorts (March 2014 and August 2014) at the University of Calgary in Canada,” the authors wrote. “Participants included children, 7 – 12 years old, with overweight or obesity (>85th percentile of body mass index) but otherwise healthy. Participants were randomly assigned to groups given either oligofructose-enriched inulin (OI, 8 g/day; n=22) or maltodextrin placebo (isocaloric dose, controls; n=20) once daily for 16 weeks. Fat mass and lean mass were measured using dual-energy-x-ray absorptiometry. Height, weight, and waist circumference were measured at baseline and every four weeks thereafter. Blood samples were collected at baseline and 16 weeks and analyzed for lipids, cytokines, lipopolysaccharide, and insulin. Fecal samples were collected at baseline and 16 weeks; bile acids were profiled using high-performance liquid chromatography, and the composition of the microbiota was analyzed by 16S rRNA sequencing and quantitative PCR. The primary outcome was changed in percent body fat from baseline to 16 weeks.”

Raylene Reimer, Ph.D., professor in the faculty of kinesiology and senior investigator on the current study showing that a fiber supplement, known as a prebiotic, changes gut bacteria and can be a potential intervention for children with overweight or obesity. [Riley Brandt/University of Calgary]

Amazingly, after taking the supplement for four months, the children between the ages of seven and 12 years had a decrease in body fat and the fat around their abdomen, which increases the risk of developing type 2 diabetes or heart disease. The fiber also decreased the amount of triglycerides—which increase the risk of heart disease—in their blood by 19%. 

“To me, what is so meaningful about this study is you can stop this trajectory of continuing to gain more and more weight,” Dr. Reimer noted. “Being overweight in childhood tends to persist into teenage years then into adulthood. This study, literally, allowed these kids to meet what would be considered normal growth rates for their age.”

In addition to the positive result of the children attaining a healthy weight gain, the youth who took the supplement changed the profile of their gut bacteria. Prebiotics, found naturally in garlic, onions, bananas, and whole wheat, act as a fertilizer for the good bacteria already in the gut. They are different from probiotics, which are live bacteria found in a variety of foods, including yogurt and sauerkraut.

The authors noted that prebiotics are inexpensive and noninvasive and could be a plausible intervention for children with overweight or obesity. The microbial findings from this study provide a foundation for a larger clinical trial in the pediatric population and show the potential for improving health by changing intestinal bacteria with diet. Although the authors did stress that obesity is a very complex issue and one that often requires multiple different strategies to help individuals achieve a healthier body weight.

“We have also recently shown that a prebiotic supplement can suppress appetite—which is one part of helping manage weight,” Dr. Reimer concluded. “Since we know that intestinal bacteria can influence what happens in the brain, we will continue to study how appetite and other functions in the brain are changed by diet and particularly fiber.”