Numerous studies suggest being overweight during middle age increases the risk of developing Alzheimer's. A new study by the National Institutes of Health found that people who are obese at age 50 may develop, or have a higher risk for, younger-onset Alzheimer's disease.
The researchers at NIH found that those with the highest body mass index at age 50 were much more likely to develop Alzheimer’s disease. BMI is a formula doctors use, based on height and weight, to estimate body fat. People at a healthy weight generally have a BMI under 25. Those with a BMI of 25 to 30 are considered to be overweight, while those with a BMI over 30 are considered obese.
Results from these studies showed that the higher a person’s BMI at midlife, the earlier they tended to develop the disease. Each one-point increase in BMI was associated with getting Alzheimer’s six to seven months earlier. Someone with a BMI of 30, for instance, might be diagnosed with Alzheimer’s 2½ years earlier than someone with a BMI of 25.
Those with the highest BMIs also were inclined to have more brain changes typical of Alzheimer’s, even if they didn’t have symptoms of the disease.
Whether losing weight and lowering one's BMI in middle age were not answered in the study; however, researchers noted that lifestyle changes could reduce the risk of developing Alzheimer's disease at an earlier age.
Carrying excess weight has been closely linked with a variety of diseases that affect the heart and blood vessels, including heart disease, high blood pressure and diabetes. Researchers speculate fat cells may produce harmful chemicals that promote inflammation in blood vessels throughout the brain, which might be a key to the onset of the disease. Additionally, more studies need to be done to actually determine how much weight and body fat affect the brain, as many factors contribute to determining who develops Alzheimer's disease, including what genes are inherited.