SHR # 2712:: New Study Finds High-fiber Diet Brings Significant Changes to Human Gut Microbiome - Dr. Katrine Whiteson Ph.D. - A short-term intervention in daily fiber consumption can significantly alter the gut microbiome and nutrient intake, according to a study led by University of California, Irvine researchers. The research was recently published by the American Society for Microbiology. Dietary fiber consists of resistant carbohydrates found in fruits, vegetables and whole grains. Fiber persists in our digestion system, and while not digestible by humans, our gut bacteria can metabolize fiber into short-chain fatty acids and other byproducts critical to human health.