fw: High Blood Sugar Linked to Lost Memory

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High Blood Sugar Linked to Lost Memory

By LAURAN NEERGAARD

AP Medical Writer

February 4, 2003, 2:33 AM EST

WASHINGTON -- Scientists have found yet another reason to slim down: The

high blood sugar so common among the overweight may contribute to the fogged

memory of old age.

A small study, published Monday in the Proceedings of the National Academy

of Sciences, showed that middle-aged and elderly people with high blood

sugar actually had a smaller hippocampus, the brain region so crucial for

recent memory.

The good news: If the findings are confirmed, simple diet and exercise could

help many people protect their brains. Maybe the threat of memory loss will

provide the final push for aging baby boomers to take those steps, said lead

researcher Dr. Convit of New York University.

" That's a great motivator to stay off the calories and stay off the couch, "

he said.

For every Alzheimer's patient, there are eight older people who suffer

enough memory loss to significantly harm their quality of life even though

they have no dementia-causing disease, said Convit, an NYU psychiatry

professor who set out to uncover the causes.

Blood sugar was a natural suspect because scientists have long known that

diabetics are at higher-than-normal risk for memory problems. Diabetes harms

blood vessels that supply the brain, heart and other organs.

The new study found that people's memory may be harmed long before they ever

develop full-fledged diabetes -- and that it's a problem of fuel, not

plumbing.

Convit studied 30 non-diabetic middle-aged and elderly people. He measured

how they performed on several memory tests; how quickly they metabolized

blood sugar after a meal; and, using MRI scans, the size of the hippocampus.

The slower those outwardly healthy people metabolized blood sugar, the worse

their memory was -- and the smaller their hippocampus was, Convit found.

Unlike most other tissues that have multiple fuel sources, the brain depends

on blood sugar for almost all its energy, Convit explained. The longer that

glucose stays in the bloodstream instead of being metabolized into body

tissues, the less fuel the brain has to store memories.

Convit's research found no specific threshold at which memory automatically

worsened. Overall, though, the slower the glucose metabolism, the worse

people did.

Once that metabolism reaches certain levels, it becomes a condition called

" impaired glucose tolerance " or pre-diabetes, thought to afflict 16 million

Americans. It strikes mostly in middle age, although people of any age who

are overweight and sedentary are at risk. Without treatment, pre-diabetes

usually turns into full-fledged diabetes, which in turn brings deadly heart

attacks, kidney failure and numerous other ailments.

Why did only the memory-crucial hippocampus seem harmed? Previous animal and

human research shows it's the region most likely damaged by any brain

insult, Convit said. Conversely, it's also a very adjustable region, with

the potential for some recovery if people bring their blood sugar under

control, he said.

Convit's study sheds important light on yet another risk of bad blood sugar,

said Dr. Fran Kaufman, president of the American Diabetes Association.

She cautioned that it was a small study that requires confirmation before

doctors test glucose solely for memory complaints.

But if confirmed, the same advice for lowering people's overall diabetes

risk -- drop a few pounds and do exercise as simple as walking 30 minutes a

day -- apparently would help protect people's brains, too, Kaufman said.

Meanwhile, the diabetes association already recommends pre-diabetes testing

for everyone 45 or older, and for younger people who are significantly

overweight and have one other risk factor: a diabetic relative; bad

cholesterol; high blood pressure; diabetes during pregnancy; birth to a baby

bigger than 9 pounds; or belonging to a racial minority.

Copyright © 2003, The Associated Press