We’ve discussed at length on this blog that dementia is on the rise. As a matter of fact, 47 million people worldwide are affected by dementia and by the year 2030 that number is expected to rise to 75 million. One other topic we’ve explored is the myriad of risk factors that can lead to dementia, obesity among them.
According to a study released in late July, researchers have concluded that having higher levels of body fat in old age has a direct correlation to reduction in cognitive function. Previous studies showed that adults who were overweight did not do as well in memory and visuospatial tasks. While these studies provided a beginning, at times they also produced contradictory results.
Researchers at St. James Hospital and Trinity College in Dublin set out to answer this question conclusively using a large-scale trial. They teamed up with scientists at the Nutrition Innovation Centre for Food and Health at Ulster University and dove into data from the Trinity Ulster Department of Agriculture aging cohort study. The data they explored includes information on 5,186 of adults over the age of 60 in Northern Ireland and Ireland. Each of the participants were assessed using an array of cognitive tests and the results were published in the British Journal of Nutrition.
Researchers found that individuals with a higher waist-to-hip ratio — a measure of obesity often thought to be more accurate than outdated BMI measurements — exhibited reduced cognitive performance. Though not conclusive, scientists believe that belly fat’s impact on cognitive ability might be due to increased secretion of C-reactive protein, which increases inflammation in the body. This chemical is developed in response to signals sent out by fat cells. In past studies, increased levels have been connected to a decline in cognitive performance.
Scientists also made a noteworthy connection with another molecule, hemoglobin A1C (HbA1C). When they controlled the levels of HbA1C in their analysis, the significant effect of belly fat on cognition disappeared.
HbA1C is a form of hemoglobin that is used to evaluate average blood glucose concentrations in people with diabetes. Previous studies have shown that insulin sensitivity in the hippocampus — the area of the brain responsible for memory storage — reduced cognitive ability in individuals with diabetes.
This study points to definitive evidence that there is a connection between belly fat and cognitive decline, which is a hallmark of Alzheimer’s disease and other dementia-related disorders. A conclusion can be reasonably drawn that reducing levels of obesity can help prevent the development of dementia. Which brings us back to the old-fashioned advice that the key to longevity as we age is a lifelong pursuit of staying physically active and maintaining a healthy diet.