The causes of Alzheimer’s disease are a mystery. Scientists know that the brain is being destroyed by the disease, but are at a loss to explain exactly why brain cells are dying.
The scientists have determined that the brains of Alzheimer’s patients are shrinking and that there are pathological structures, known as plaques and tangles, which appear in the brains of these patients. The plaques are made up of a protein called beta-amyloid that builds up between nerve cells. The tangles are made from another protein called tau protein, and look like twisted fibers that form throughout the brain.
Scientists know that even normal brains tend to accumulate these plaques and tangles as they age, but that Alzheimer’s patients have many more of them. Plaques and tangles, however, do not explain the disease. Scientists have been unable to connect the plaques and tangles with the death of brain cells.
The cause of the disease will eventually be discovered, but for now, scientists discuss the cause of Alzheimer’s disease in terms of risk. You are more likely to have Alzheimer’s disease if you have had a head injury, heart disease, smoke cigarettes, drink excessive alcohol, are not socially active, or are not physically active.