Low carb diet ups colorectal cancer risk

"Long term use of a diet with very low carbohydrate such as Atkins diet may increase risk of colorectal cancer in humans as low carb diet reduces the amounts of beneficial bacteria, according to a new study.

Scientists at Aberdeen's Rowett Research Institute found that a very low carbohydrate weight loss diet causes a four-fold reduction in the numbers of certain types of bacteria in the gut of obese men. These bacteria are known to produce a chemical known as butyrate, which has been shown to be protective against colorectal cancer.

Butyrate, a short chain fatty acid, is produced in the gut only when the bacteria ferment the carbohydrate present in food. It can be used by the bacteria as a source of energy and also is used by the cells which line the gut wall. "