It was once believed that a diet high in fibre protected against bowel cancer. It is now believed that "resistant starch" is the substance which provides the protection.
In populations where a large proportion of the diet is unrefined starch, there is a much lower death rate from cancer of the colon and other degenerative diseases.
Resistant starch - which is starch that is not easily digested by the body - has a chemical and physical structure which acts as a protective agent for certain bacteria (probiotics) allowing them to survive better in the gut.
Probiotics are bacteria which are ingested in foods like yoghurts, and they have been found to modify the physiology of the gut. The probiotics modify the immune system promoting a healthier body. Resistant starches allow probiotics to be present in larger numbers thus protecting against disease.
