Bacteria, Fiber and Adenomas
Research clearly shows that consuming high amounts of dietary fiber reduces risk of colorectal cancer and now, a study adds to the evidence suggesting that our millions of gut bacteria may play a role.
The study, published in The American Journal of Clinical Nutrition, focuses on advanced colorectal adenoma, a non-cancerous tumor that has the potential to develop into cancer. It suggests that a high-fiber diet increases the abundance of healthy gut bacteria and its byproducts, and may reduce the risk of advanced colorectal adenomas.
This study included approximately 700 Chinese patients over 50 years old who had answered questions about their eating habits over the past five years. About half were diagnosed with advanced colorectal adenomas. The study found that the adenoma and the healthy groups had distinctly different bacteria types in their gut. Previous research has suggested that the compounds produced when gut bacteria digest fiber – such as butyrate – may play a role in colon cancer prevention. Those who consumed higher amounts of fiber produced higher amounts of butyrate and were less likely to have advanced adenoma. In general, patients with advanced colorectal adenoma had significantly lower amounts of butyrate.
The quantity of butyrate-producing bacteria was far greater in the high-fiber healthy group than in their counterparts who ate a low-fiber diet or the high-fiber group with adenomas.
Source: Ameena Batada et al. "Decreased dietary fiber intake and structural alteration of gut microbiota in patients with advanced colorectal adenoma." Am J Clin Nutr May 2013.