Читать книгу Alzheimer's Disease - Michelle Deetken - Страница 22

Diabetes is the major metabolic condition involving glucose, with the hormone insulin being at the core of the problem. Excessive glucose consumption along with a diet high in protein can lead to type 2 diabetes. Why? Protein and carbohydrates regulate each other. This balance is maintained when consuming a meal of plant proteins and complex carbohydrates—for example, brown rice and beans. The balance becomes lopsided when consuming too much meat, a highly concentrated protein, which causes a sugar craving as the metabolism attempts to reestablish its protein/carbohydrate balance. Additionally, consuming a great deal of glucose increases the desire for more protein to retain the balance; and as this cycle continues, overeating and obesity may occur. Maintaining this balance when there is too much glucose in the system may cause the pancreas to produce a large amount of the hormone insulin, which regulates glucose. The over-production of insulin causes the body cells and the brain neurons to become less sensitive or resistant to the insulin, triggering glucose levels to rise even more. This rise in glucose levels stimulates the pancreatic cells to make even more insulin, eventually exhausting the pancreas and its ability to function at all. Obesity and insulin resistance have recently been associated with cognitive decline and Alzheimer's disease. The growing prevalence of obesity today, especially among younger people where it is estimated that one third of the population is obese, raises the possibility that AD and other dementias may activate at earlier ages (Hildreth, Van Pelt, and Schwartz, 2012).

One characterization of Alzheimer's disease is a decrease in glucose metabolism and brain metabolic activity in some areas of the brain due to inadequate levels of glucose. These areas also have numerous neurofibrillary tangles. This feature suggests that an altered energy balance may induce tau to become abnormal, which makes the neuronal cytoskeletal system more prone to oxidation. Consequently, the death cycle begins because the cell is starving from a lack of glucose (Planel, E., et al., 2001).