For some time I have been reading papers dealing with the association (or lack thereof) of obesity with neurological disorders, such as Alzheimer’s Disease, autism spectrum disorders, and ADHD. I did not report on them too much, even though I came into the obesity field through my advocacy work in the neurosciences in the 1990s. I just did not ‘get’ the connection.
Now, the veil has been lifted thanks to a talk by Tamas L. Horvath, of Yale University. Dr. Horvath’s talk, at the Research Symposium sponsored by the American Diabetes Association, “Biologic Responses to Weight Loss and Weight Regain,” in Washington DC in April 2013, focused on hunger-producing neurons’ regulation of higher brain functions and longevity.
One slide in particular caught my attention. He was addressing the complexity inherent in satisfying the hunger drive and appetite needs. For example,
-wakefulness is needed. This is controlled by the lateral hypothalamic arousal center. Disorders in wakefulness include narcolepsy and sleep disorders.
– memory of the location of food sources is needed, both long term and short term. This is the role of the brain’s memory and reward systems. Disorders in this realm include dementia, Alzheimer’s disease, mood and addictive disorders.
-decision-making for when and how to acquire and prepare food is required. Related disorders in this sphere include depression and schizophrenia.
-the physical ability to pursue and locate and collect food is needed. Related disorders include Parkinson’s disease and amyotrophic lateral sclerosis (ALS).
-finally, there is food intake itself. Related disorders include obesity, anorexia and diabetes.
This simple schema made a great deal of sense to me. So, with thanks to Dr. Horvath, we will start providing more reports of studies investigating the connections of obesity and these prominent neurological conditions.
For example, Fadel and colleagues are looking at insulin, orexin and leptin, already recognized for regulating food intake, body weight and body composition, for their involvement in addictive behaviors, reproduction and cognitive performance. See, Food for thought: the role of appetitive peptides in age-related cognitive decline.
Vignini et al discuss the association of diabetes mellitus with Alzheimer’s Disease, calling Alzheimer’s Disease “Type 3 Diabetes.” Their paper, “Alzheimer’s disease and diabetes: new insights and unifying therapies” explores common mechanisms and possible remedies for both diseases. Meanwhile, Reitz and colleagues have uncovered variants in the FTO gene (already implicated for obesity) which can be risk factor for Alzheimer’s disease.