The body needs a constant supply of glucose, not only because it is an important energy source, but because certain tissues such as the brain and nerves cannot function without it. For this reason glucose levels are precisely controlled by the two hormones glucagon and insulin. Insulin is produced by the islets of Langerhans of the pancreas, and its function is to lower blood glucose levels by stimulating the conversion of glucose to a storable form of energy such as fat. The hormone glucagon has the opposite effect and increases the glucose levels. The ailment diabetes mellitus results from a lack of insulin production, whereas excessive insulin production results in hypoglycaemia or low blood sugar. Rapid uptake of glucose can be brought about by a refined food diet and can lead to hypoglycaemia or, in the case of the diabetic, it can be brought about as a result of an insulin injection.
Monosaccharides such as glucose, fructose and galactose require no digestion and are absorbed as is. The disaccharides, such as sucrose, are rapidly converted by the glycosidases in the intestine and it is easy to flood the system with glucose if refined foods are consumed. The subsequent glucose surge will lead to extensive insulin production, and because the glucose will then be converted to fat and glycogen, the blood sugar levels will be lowered more than normal, thus leading to hypoglycaemia. Hypoglycaemia initiates a series of bodily responses and the reduced glucose levels are recognized by the brain, which in turn triggers a response by the sympathetic nervous system. Adrenalin and other hormones are then released to counteract the fall in glucose levels, and this manifests itself in numerous symptoms of which only a few
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