When food enters the body, the carbohydrates in the food are broken down in the stomach to produce simple sugars such as “glucose”. Then, it is absorbed by the small and large intestines and released into the bloodstream. The glucose present in the blood can be immediately used by the cells as “energy” or stored as “glycogen” in the liver, to be used later. During fasting or in the absence of glucose, the stored glycogen is converted back to glucose and is utilized as energy.
If excess glycogen is formed, the liver converts it into “fat” and stores it in the adipose tissue (fat cells). Usually, this type of fat is a long-term fat, as it is hard to burn.
Moreover, the body needs “insulin” to carry the glucose into the cells of the body. Insulin is a hormone produced by the beta cells of the pancreas. Beta cells can sense the amount of glucose present in the blood and produce the required amount of insulin. The blood glucose is higher immediately after a meal, but insulin reduces it to normal after a few hours.
This rise and fall of glucose and insulin occur many times in a day. And depends on the type and the amount of food ingested. For instance, when a person eats a piece of bread, the blood glucose rises and the beta cells are triggered to release more insulin into the blood. After a few hours, the blood glucose drops to normal range. However, this mechanism is impaired in patients with certain medical conditions such as diabetes.
Diabetes mellitus is a chronic disease caused by the inability of the pancreatic cells to produce insulin, or due to defective uptake of glucose by the cells of the body. There are three types of diabetes:
- Type 1 (insulin-dependent) - it is usually seen in children. The body produces very less or no insulin.
- Type 2 (non-insulin dependent) - it is usually associated with obesity. Type-2 diabetes is common in adults but may also occur in children. In this type, the cells of the body are unable to utilize the insulin (insulin resistance).
- Gestational - high blood levels during pregnancy, associated with complications in both mother and child. The child born is at increased risk of developing type 2 diabetes later in life.