Is Excess Body Fat Hurting Your Brain?

It's a terrifying, recurring theme in our nation, one that I hope you'll truly grasp and one that will motivate you to make real lifestyle changes: The obesity epidemic is taking its toll on the health of America.

The Centers for Disease Control says 2 out of 3 adults and 1 in 6 children in the U.S. are overweight or obese. Since the mid-1970s, the percentage of obese American adults has more than doubled, and the percentage of overweight or obese children has nearly tripled. The bigger picture? Being overweight can lead to type 2 diabetes, hypertension, heart disease, some cancers, osteoarthritis, sleep apnea, depression and a host of other ailments.

And now we have another reason to shed those extra pounds: Researchers may have found a link between high body fat and decreasing cognitive function, Alzheimer's and other forms of dementia.

Fat study. A study in the March 2009 issue of Archives of Neurology investigated "whether total and/or regional adiposity [high fat levels]...influences cognitive decline in older adults and whether this association is explained by hormones and inflammatory factors known to be secreted by adipose [fat] tissue."

Researchers measured adiposity of 3,054 seniors over a seven-year period, then looked for links between "baseline body fat measures and change in Modified Mini-Mental State Examination (3MS) score."

Men at risk. In men, worsening cognitive function correlated with the highest levels of all adiposity measures. According to the study, "total body fat and subcutaneous abdominal fat are the two adiposity measures with the strongest effect on cognitive change in men," findings that are consistent with both the Framingham Heart Study and a large Danish study. The study revealed no

association between adiposity and cognitive change in women.

Women not exempt. In a study by University of California's Dr. Kristine Yaffe, women who had more metabolic syndrome components (a group of cardiovascular risk factors such as abdominal obesity, high blood pressure and low HDL cholesterol levels) showed a 23% increase in cognitive impairment over a four-year period.

Then a June 2009 article in the online Archives of Neurology reported on a 15-year-long study in which magnetic resonance imaging (MRI) scans were taken of the brains of 48 postmenopausal women to determine their white and gray matter volume.

Females having the lowest gray matter were ones with the most weight gain. Since they were healthy and without the typical "high blood pressure, impaired glucose tolerance" problems of overweight females, you have to wonder if weight gain alone directly impacts brain functionality.

Heads up, middle-agers. Midlife obesity is linked to dementia. Researchers led by University of Washington's Dr. Annette L. Fitzpatrick reviewed data from 2,798 dementia-free participants (average age 74.7). Obese participants in their midlife were more inclined to demonstrate dementia than their slimmer counterparts. But after age 65, underweight participants were more likely to develop dementia.

What that means to you. Though the mechanism may not be fully understood, the studies all point to this: Maintaining a healthy weight now may reduce cognitive decline later on-more proof that the right nutrition really does matter.