Posted on Jul 24, 2012, 6 a.m.
Dietary fiber promotes the growth of beneficial bacteria.
Microbes that live in the gut are responsible for fermenting fiber in the intestine, producing short-chain fatty acids and other metabolites better beneficial for the body. It is therefore important that sufficient dietary fiber is consumed daily, in order to promote the growth of such beneficial bacteria. Kelly Swanson, from the University of Illinois (Illinois, USA), and colleagues studied 20 healthy men, consuming an average fiber intake of 14 g a day, who were given snack bars to supplement the diet. A second group ate bars that contained 21 grams of polydextrose, which is a common fiber food additive; a third group received bars with 21 grams of soluble corn fiber; and a fourth group received bars that contain no fiber. The team collected fecal samples from the subjects, and used the microbial DNA they obtained to identify which bacteria were present. DNA was then subjected to 454 pyrosequencing, a technique that provided a snapshot of all the bacterial types present. The researchers found that certain bacteria grew as a result of the respective fibers consumed. Observing specifically that when soluble corn fiber was consumed, the numbers of Lactobacillus bacteria, often considered as a probiotic for its beneficial effects on the gut, increased.
Seema Hooda, Brittany M. Vester Boler, Mariana C. Rossoni Serao, Jennifer M. Brulc, Michael A. Staeger, Kelly S. Swanson, et al. “454 Pyrosequencing Reveals a Shift in Fecal Microbiota of Healthy Adult Men Consuming Polydextrose or Soluble Corn Fiber.” J. Nutr., July 2012; 142: 1259-1265.