Dietary Fiber Boosts Good Gut Bacteria

URBANA, Ill. Dietary fiber supports good gut bacteria growth that can support a healthy gastrointestinal tract as well as affect a persons  susceptibility to conditions as varied as type 2 diabetes, obesity, inflammatory bowel disease, colon cancer, and autoimmune disorders such as rheumatoid arthritis, according to a new study published in the Journal of Nutrition.

Researchers at the University of Illinois Department of Animal Sciences recruited 20 men with an average fiber intake of 14 grams a day. They were then given food bars as supplements to their diet. Participants were randomly assigned into three groups. The control group received bars that contained no fiber; a second group ate bars that contained 21 grams of polydextrose, which is a common fiber food additive; and a third group received bars with 21 grams of soluble corn fiber.

On days 16-21, fecal samples were collected from the participants, and researchers used the microbial DNA they obtained to identify which bacteria were present. DNA was then subjected to 454 pyrosequencing, a fingerprinting" technique that provides a snapshot of all the bacterial types present.

Both types of fiber affected the abundance of bacteria at the phyla, genus and species level. When soluble corn fiber was consumed, Lactobacillus, often used as a probiotic for its beneficial effects on the gut, increased. Faecalibacterium populations rose in the groups consuming both types of fiber.

The researchers said the shifts in bacteria seen in this studywhich occurred when more and differing types of fiber were consumedwere the opposite of what you would find in a person who has poor gastrointestinal health. That leads them to believe that there are new possibilities for using pre- and probiotics to promote intestinal health.

For example, one type of bacteria that thrived as a result of the types of fiber fed in this study is inherently anti-inflammatory, and their growth could be stimulated by using prebiotics, foods that promote the bacterias growth, or probiotics, foods that contain the live microorganism," they said.