The pancreas is a gland which lies near the liver, stomach, and duodenum. It has a number of secretions, some of which go directly into the intestine and are concerned with digestion. One secretion goes instead into the blood and is intimately concerned with the way in which the body uses sugars. This substance is called insulin. A deficiency of insulin in the body results in a chronic disease called diabetes mellitus. Diabetes has been known for thousands of years and was described by ancient Greek and Chinese writers, who were principally concerned with the large amounts of fluids excreted by the body in this condition. The fact that the urine contained sugar was first noted in the seventeenth century. Not until 1889 was it proved that diabetes results from failure of the pancreas. In 1921 Banting prepared an extract of the pancreas which is now called insulin. At least a million people now in the United States have diabetes, and the number increases, because the condition tends to come on with advanced years. More than half the people with diabetes develop the condition before they are fifty years old. Women are affected more frequently than men, particularly in diabetes in advanced years.
Studies of diabetes show that heredity plays an important part. This relationship is becoming more and more clear as people with diabetes tend to live longer and have more children. Once diabetes in childhood was considered invariably fatal. Now these children grow up, marry, and have families. We now know that if both parents are diabetic, the children will most certanly inherit the disease. Overweight is also important in relationship to diabetes. Not everyone who is overweight develops the disease. In fact, diabetes is seen in only a small proportion of the people who are overweight. However, nine out of ten people who develop diabetes are overweight. Among those who are overweight and who develop diabetes, dieting and restoration to normal weight lessens the severity of the symptoms and sometimes controls the condition. The person who is overweight, however, can produce more and more insulin and this may be a factor in exhausting the function of the pancreas. As I have mentioned in previous articles, both the pituitary gland and the adrenal glands are also related in their functions to the use of sugar by the body. Excessive action of the pituitary gland may result in the appearance of sugar in the urine. Excessive action of the thyroid gland may make diabetes worse by increasing the work of the gland, through the fact that the person is taking in large amounts of food.