Lower Body Weight as we Age Linked to Increased Alzheimer’s Disease Risk

Many lifestyle factors are associated with the development of the memory-robbing form of dementia known as Alzheimer’s disease. Smoking, diet, lack of exercise and poor B-vitamin status all contribute to the sixth most prevalent cause of death each year in the US. Past studies have shown that excess weight in mid-life increases the risk of developing Alzheimer’s disease.

Evidence published in the journal Neurology finds that low body weight (as measured by Body Mass Index or BMI) is a strong predictor for those at risk of developing this most devastating form of dementia. Proper weight management at all stages of life is critical to lower the risk for developing Alzheimer’s disease.

Underweight during Advancing Years Associated with Increased Alzheimer’s Disease Risk

Natural health followers have long known that excess abdominal fat and obesity are critical factors that promote an unhealthy cascade of metabolic reactions that lead to cognitive decline and eventually, Alzheimer’s disease. The result of a new study explains the delicate relationship between body weight and dementia risk, as advancing years and a lower BMI are show to significantly increase risk for future development and progression of the disease.

Researchers examined 506 people with advanced brain imaging techniques and analyses of cerebrospinal fluid (CSF) to look for biomarkers associated with Alzheimer's disease. Many biochemical markers are known to be present years before the first symptoms begin. The group was comprised of people with no memory problems, people with mild cognitive impairment, or mild memory problems, and people with a diagnosis of Alzheimer's disease.

Study Finds Direct Link between Low BMI and Amyloid Brain Plaque Formation

After testing body weight and reviewing the results of CSF and brain imaging tests, scientists found that in people with no memory or thinking problems and in people with mild cognitive impairment, those who had the Alzheimer's biomarkers were also more likely to have a lower BMI than those who did not have the biomarkers. Dr. Jeffrey Burns, the study leader noted, “85 percent of the people with mild cognitive impairment who had a BMI below 25 had signs of the beta-amyloid plaques in their brains that are a hallmark of the disease, compared to 48 percent of those with mild cognitive impairment who were overweight.” 

Researchers conducting the study determined that low body weight and advanced age may result in damage to an area of the brain called the hypothalamus that plays a role in regulating energy metabolism and food intake. Dr. Burns concluded “These results suggest Alzheimer's disease brain changes are associated with systemic metabolic changes in the very earliest phases of the disease.” The information provided by this study underscore the importance of maintain a healthy body weight (for most people measured with a BMI range of 20 to 25) throughout life and advancing years to lower the risk of developing Alzheimer’s disease.