The Bigger Your Belly, The Smaller Your Brain

Belly fat: image via shinyhealth.comResearchers from Boston University School of Medicine and other U.S. medical centers have studied the relationship of various markers of body fat to brain markers for Alzheimer's disease, and their findings are not good for those who have fat around their mid-sections, or 'belly fat.
The researchers sampled 733 participants of the Framingham Study Offspring Cohort with a mean age of 60, who had undergone a variety of measurements: body mass index (BMI), waist circumference (WC), waist-to-hip ratio (WHR), computed tomography (CT)-based measurements of subcutaneous (SAT), and visceral (VAT) adipose tissue, as well as MRI measures of total brain volume (TCBV).   Correlations were made between each of the body fat measurements and TCBV as well as other brain markers seen in aging brains that indicate increased risk for dementia and Alzheimer's disease.

Normal brain (above) with Alzheimer's brain (below): image via rejuvenal.info An inverse relationship was found between BMI and TCBV (i.e., a higher BMI correlated with lower TCBV), but the strongest inverse relationship occurred between VAT and TCBV (i.e., a higher VAT correlated with TCBV).  This suggests that abdominal fat may be a better indicator for dementia risk than BMI. Those with smaller brain volumes tend to do poorly on tests even before other signs of dementia are apparent.

This study shows that belly fat, which poses greater risk of heart disease, also presents a greater risk for dementia.  But if you're younger than 60, you're not out of the woods.
Dr. Sudha Seshadri, M.D, lead researcher, said "Our results confirm the inverse association of increasing BMI with lower brain volumes in older adults and with younger, middle aged adults..." (italics mine)
"Our findings, while preliminary, provide greater understanding of the mechanisms underlying the link between obesity and dementia," concluded Dr. Seshadri. "Further studies will add to our knowledge and offer important methods of prevention."