We think it is more important than ever before as it might show up five to ten years before Alzheimer’s disease begins to control the brain.

Alzheimer’s disease has been linked to obesity in old age. Understanding the link between brain health and body weight is essential since by 2030, 85% of American adults are expected to be overweight or obese, and by 2050, dementia is expected to affect 131 million individuals globally.

In a recent study, scientists from The University of Texas Health Science Center at San Antonio (UT Health San Antonio) found a link between obesity and 21 genes associated with Alzheimer’s disease, offering a potential mechanistic explanation for why adults who experienced obesity in midlife may or sometimes be more likely to develop Alzheimer’s.

The results from 5,619 Framingham Heart Study participants were published in Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association today.

The study team evaluated 74 genes associated with Alzheimer’s using Framingham data. In obesity, 21 of the genes were either under-expressed or over-expressed.

Gene expression refers to the activation of a gene in a cell to carry out tasks like producing a protein.

The research discovered a relationship between body mass index (BMI) and 13 genes connected to Alzheimer’s. The waist-to-hip ratio, a second measure of obesity, was linked to eight genes.

“Several of the genes were more strongly related to obesity in midlife versus in late life, and also to obesity in women versus men,” remarks corresponding author Claudia Satizabal.

These findings are consistent with previous epidemiological research that showed midlife obesity may be a risk factor for Alzheimer’s disease in women, according to Satizabal.

Surprisingly, those who acquire dementia tend to lose weight five to ten years before the condition manifests itself. There might be unhealthful weight loss caused by the condition.

“We think it is more important to address obesity and begin healthy weight loss in midlife, in one’s 40s and 50s, when obesity may be impacting expression of the genes we studied,” adds Satizabal.

While BMI is the most often used indicator of obesity, some research suggests that the waist-to-hip ratio, which measures abdominal obesity (belly fat), is a more sensitive indicator of metabolic dysregulation in people. One of the main risk factors for heart disease and stroke, obesity is a part of the metabolic syndrome.

According to first author Sokratis Charisis, the 21 dementia-related genes associated with obesity are known to be involved in various Alzheimer’s disease processes such as neuro-inflammation, programmed cell death, and amyloid-beta protein accumulation in neurons.

The Framingham Heart Study is conducted in a mostly white population.

“We think the associations between Alzheimer’s-related genes and obesity might be even more relevant in Hispanics, who have a higher prevalence of obesity, but that is yet to be tested,” adds Satizabal. “We need to increase the sampling of diverse populations to find more genetic markers related to dementia.”

Source: 10.1002/alz.12954

Image Credit: Getty