The end product of rancidity is peroxides which are harsh irritants. Carbohydrates are primarily concerned. Nitrogen is the principal component of intestinal gas. Nature is normally a good intestinal housekeeper. Both bile and hydrochloric acid have antiseptic effects.
Digestive enzymes assist by keeping down the presence of undigested foods.
Many foods have a beneficial effect in maintaining the intestinal environment. Some foods are to be watched with a suspicious eye. Recently, a number of articles have appeared in medical journals reporting on malabsorption syndrome caused by the eating of a common food. The offending factor discussed is gluten. Gluten is the substance in wallpaper paste which provides it with its adhesive quality.