Why doesent the human body digest sweet corn?
We can digest the starchy kernel, but not the yellow coat, which is primarily made of the glucose polymer cellulose (humans, like most if not all mammals, do not produce a cellulose-digesting enzyme). The coats of peas and beans are also made of cellulose, but are much thinner, allowing us to grind them up into smaller fragments when we chew, but we cannot digest them either. Cellulose is the primary component of dietary fibre (‘roughage’), which aids the passage of food through our long and winding intestinal tracts by giving the gut wall muscles some indigestible bulk to push against. Low-fibre diets can lead to constipation, especially if combined with a high intake of red meat (for which our digestive systems are also poorly adapted).
