To fight harmful bacteria in the urinary tract, encourage the growth of helpful bacteria. To encourage the growth of healthy symbiotic bacteria in your digestive system, consume fibre. Dietary fibre increases the bacteria in the large intestines which require nitrogen for their growth. This in turn reduces the chances of cancerous changes in cells by reducing the amount of ammonia in the large bowel. Fibre reduces the absorption of cholesterol in the diet. It also slows down the rate of absorption of sugars from the food in the digestive system. Certain types of fibre increase the viscosity of the food content. This increased viscosity indirectly reduces the need for insulin secreted by the pancreas. Thus a fibre-rich diet can help in diabetes mellitus.