Body Shape May Affect Mental Acuity

[Avnish Jolly]

Body Shape May Affect Mental Acuity
http://www.usnews.com/science/articles/2010/07/15/body-shape-may-affect-mental-acuity.html

Big apples fare better than plump pears
Posted: July 15, 2010


By Janet Raloff, Science News

Being fat may diminish mental performance, studies find — a problem
that worsens with age. But among elderly women, where fat is deposited
may matter. To wit: The big apple is sharper than the obese pear.


Genetics dictates where people preferentially accumulate body fat. For
most it’s around the belly. Among the obese, these apple-shaped
individuals tend to run a bigger risk of developing heart disease than
do pears — people who deposit most of their excess fat at the hips and
thighs. For a host of reasons, physicians had expected that if body
shape affected mental performance, apples would again prove the bigger
losers.

In fact, the opposite appears true, Diana Kerwin of Northwestern
University’s Feinberg School of Medicine in Chicago and her colleagues
report online July 14 in the Journal of the American Geriatrics
Society.

The team pored over data collected from more than 8,700 women, all 65
to 79 years old. These were a healthy subset of incoming participants
to the Women’s Health Initiative study. This long-running trial at 40
medical centers across the country has been investigating the role of
hormone-replacement therapy and diet on risk of heart disease,
fractures and certain cancers.

Each woman was administered a test of memory and reasoning known as
the Modified Mini-Mental State Examination, or 3MSE. Kerwin’s team
correlated a participant’s score with her shape and her height-
adjusted weight — something known as body-mass index, or BMI. BMI
values were divided into six categories, with 1 being lean and 6
morbidly obese.

Most women scored within the normal range of 90 to 100 on the 3MSE,
Kerwin notes. However, among pear-shaped overweight women, for every
increase in BMI category, the 3MSE score dropped by roughly half a
point. This held even after adjusting for potentially confounding
factors such as age, education and cardiovascular disease risk. How
memory and reasoning might have altered over time remains unknown,
Kerwin observes, since women took the cognitive test only once, upon
entering the study.

Among apples, the fatter they were, the higher their mental-acuity
score, although the difference from slim to morbidly obese was only
around 2 points out of 100 possible — and the biggest increase
occurred between the slim and normal-weight categories.

“Apples were better? That is surprising,” says geriatrician John
Morley of the Saint Louis University School of Medicine. “It’s very
difficult to explain,” he says, because based on blood levels of
triglycerides, or fats, “the higher levels (which you get in the
apple, not in the pear) interfere with memory.” On the other hand, he
notes, “fat produces leptin [a hormone that plays a role in regulating
fat storage]. And we’ve shown that leptin increases memory. It’s
really the fat around the stomach that is a leptin producer.”

Kerwin says her data indicate the link between body shape and
cognition is complex. For instance, slim to normal-weight, very pear-
shaped women had the highest mental-acuity scores and lean apples the
lowest. Overall, normal-weight women tended to outperform overweight
women of either shape. So, she argues, there’s no advantage in normal-
weight women becoming big apples.