Visceral Fat and Diabetes

Diabetes mellitus, often simply referred to as diabetes, is a pathological condition characterized by chronic high level of glucose in the blood stream (hyperglycemia). Defect in insulin production is the main cause of diabetes. Insulin is a molecule produced by the beta cells in the Islets of Langerhans and is responsible of glucose uptake from blood stream to cells. When glucose uptake is chronically impaired we have diabetes. Diabetes can be divided in type 1 and type 2. Type 1 diabetes is characterized by a total lack of insulin production due to specific autoimmune destruction of beta cell of the islets of Langerhans in the pancreas. Type 2 diabetes is due to a reduced production of insulin as a result of an inflammatory process of the fat tissue.

While the exact cause of type 1 diabetes is unknown, type 2 diabetes etiology instead is strictly related to obesity. Excess accumulation of fat, especially in visceral depots, produces secretions of bioactive components involved in metabolic dysfunctions and inflammation. Adipose tissue acts as an endocrine organ responsible of dramatic changes in metabolism and immune response. The first step of the pathology is called "insulin resistance", a condition characterized by a reduced sensitivity of the cells to insulin.
Insulin resistance occurs as a combination of events. On one side we have an overproduction of molecules (acyl-CoA) involved in the degradation of fatty acids in response to an altered lipid metabolism. Excess acyl-CoAs are then transformed in diacylglycerols and ceramides that interfere with the machinery of glucose uptake in the cells. On the other side we have a low-grade systemic inflammation process characterized by macrophage infiltration in adipose tissue and the production of inflammatory mediators (adipokines and cytokines) that also interfere with the glucose uptake machinery of the cells. In this early stage of the pathology the insulin levels in the body are higher than normal. This is due to the effort of the pancreas to compensate the reduced sensitivity of the cells to insulin.
Chronic inflammation of adipose tissue has another important effect. It reduces the functionality of the islets of Langerhans in the pancreas. The result is a diminished production of insulin. The combination of both factors, insulin resistance and limited insulin production, is responsible for the onset of type 2 Diabetes.
In conclusion, the links between type 2 diabetes and obesity are firmly established. Research shows that the visceral accumulation of fat is strictly related to the onset of the disease. When the abdominal circumference exceeds 102 cm (40 inches) in men and 88 cm (35 inches) in women the risk increases dramatically.
The message to take home is that we need to take control of the amount of our visceral fat. This can be accomplished through a healthy and balanced diet in addition to daily aerobic exercise (8000 steps a day are considered a golden standard). Without the intervention of a healthy diet and appropriate exercise, obesity may develop into diabetes over a relatively short period of time.

Keywords *

diabetes, insulin resistance, hyperglycemia, obesity, adipose tissue, inflammation, visceral fat

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Alessandro Mastrogiacomo Ph.D. is a Neurochemist and Nutritionist. He is interested in the action of food on the physiology and toxicology of the nervous system and expert in Mediterranean diet.


Author *

Alessandro Mastrogiacomo