As scientists continue to research obesity and its effects on the body, the phrase “Food for thought” takes a whole new meaning. Can too much food have negative effects on the brain and its function? Sadly for an America with a growing population of obese individuals, the answer is yes. It has been shown that overnutrition, or the chronic over consumption of food, can impact the brain by causing inflammation, causing structural changes, and elicit cognitive deficits as a result.
Inflammation
The hypothalamus is a common place in the brain that is found to be inflamed when it is exposed to overnutrition. Because of the role of the hypothalamus in the brain, cytokines that are released when the hypothalamus is inflamed can be related to obesity-induced hypertension and problems with insulin resistance. These inflammatory cytokines from the hypothalamus have recently been shown to reduce neuronal insulin secretion, increased systemic insulin resistance, and increase markers in the body for programmed cell death of pancreatic cells. In obesity research it is still unknown whether overnutrition stimulated hypothalamic inflammation or if hypothalamic inflammation contributes to an individual’s cause for obesity, but the hypothalamus is still a hot part of the brain because it is such an important regulatory region for the entire body.
Structural Changes
Medical imaging of obese people and their normal weight counterparts has also shown structural differences in the brains of people who are obese. People who were obese showed to have decreased brain volumes independent of age or brain disease. A recent report indicates that BMI is linked to a reduction of white matter in the brain as well. Research is also exploring the effects on the gray matter in the frontal lobe, and blood supply to the prefrontal cortex. Though the reason for these structural changes in the brain has not been totally pinpointed, it is hypothesized that inflammation, breakdown of the blood brain barrier, and insulin resistance associated with high-fat diets may be contributing factors.
Cognitive Defects
Related to inflammation of the brain and structural differences in brains of obese individuals, comes the question of any cognitive deficits that may be associated with the condition. Many studies are finding that obesity during midlife is a predictor for mild cognitive impairment during old age. Closely related to this is the onset of dementia and Alzheimer’s. Currently, normal weight people have a relative risk of about 1.64 for developing dementia or Alzheimer’s while the relative risk for obese individuals is about 2.4. As for the entire age spectrum of the population, obese individuals statistically score lower on short-term memory and executive function tests than normal weight individuals.
When people think about the health risks associated with obesity, the brain is often the last organ that is worried about. Recent research is making people think otherwise. As more and more research is bashing overnutrition and obesity, the negative effects on the brain are coming to surface as well. Reducing the risk of brain-related illnesses later in life is just another reason overweight Americans should look at improving their health with a little exercise and a healthier diet.
