Obesity shrinks critical brain regions and increases the risk of getting Alzheimer's disease. Two recent studies have outlined the risk of being obese with regard to the health of the brain as we age. A gene called FTO (for Fat Mass and Obesity) has been linked to obesity; it appears to play a critical role in determining body mass index and, when present, increases the risk of developing diabetes - a disease that also has been linked to getting Alzheimer's disease. The FTO gene is particularly active in the feeding centers of our brain and in our pancreas, the organ that controls the release of insulin. In a nine-year study involving over 1000 Swedish adults over the age of 75, those people who had a particular version of this gene were 58% more like to develop Alzheimer's disease!
A second study just published in the Neurobiology of Aging determined that a higher body mass index was associated with shrinkage in every region of the cortex! These findings are consistent with earlier studies claiming that increased body fat increases the risk of developing Alzheimer's disease. The elderly obese also have more impaired learning and memory abilities than elderly thin people. Last year, a study published in Clinical Neuropathology demonstrated that obese patients with Alzheimer's disease actually have more pathology in their brains and a more rapid mental decline. Being obese at mid-life is also a strong predictor of dementia in later life. Oddly, later in life, most dementia patients tend to rapidly lose weight as the disease progresses.
How does obesity contribute to brain shrinkage and cognitive decline? A few years ago it became clear that fat cells produce inflammation by releasing specialized proteins called cytokines. The more fat cells you have the more cytokines get released into your blood. I study the effects of cytokines in the brain. A few years ago I discovered that these proteins are capable of inducing shrinkage of brain regions that are used in the process of learning new things and recalling old memories. The longer the inflammation progressed, the more shrinkage occurred and the greater was the memory loss.
The good news is that the consequences of inflammation due to body fat are likely to develop slowly and require many years to be fully expressed. However, the sooner one loses the fat the sooner the brain can begin to recover. This risk factor is preventable! If you are a women (because obese women are at greater risk than obese men), and if you have older relatives, particularly women, who have Alzheimer's disease, then you many reasons to start losing those extra pounds today.
[Copyright by G.L.Wenk, Ph.D. Publications on material mentioned here can be downloaded from my web site: http://faculty.psy.ohio-state.edu/wenk/]
