[THS] Eating foods rich in vitamin E associated with lower dementia risk

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Eating foods rich in vitamin E associated with lower dementia risk

July 12th, 2010 in Medicine & Health / Neuroscience

Consuming more vitamin E through the diet appears to be associated with a lower
risk of dementia and Alzheimer's disease, according to a report in the July issue of
Archives of Neurology.

Oxidative stress—damage to the cells from oxygen exposure—is thought to play a role
in the development of Alzheimer's disease, according to background information in
the article. Experimental data suggest that antioxidants, nutrients that help repair this
damage, may protect against the degeneration of nervous system cells. "Although
clinical trials have shown no benefit of antioxidant supplements for Alzheimer's
disease, the wider variety of antioxidants in food sources is not well studied relative to
dementia risk; a few studies, with varying lengths of follow-up, have yielded
inconsistent results," the authors write.

Elizabeth E. Devore, Sc.D., of Erasmus Medical Center, Rotterdam, the Netherlands,
and colleagues assessed 5,395 participants 55 years and older who did not have
dementia between 1990 and 1993. Participants underwent a home interview and two
clinical examinations at the beginning of the study, and provided dietary information
through a two-step process involving a meal-based checklist and a food
questionnaire.

The researchers focused on four antioxidants: vitamin E, vitamin C, beta carotene
and flavonoids. The major food sources of vitamin E were margarine, sunflower oil,
butter, cooking fat, soybean oil and mayonnaise; vitamin C came mainly from
oranges, kiwi, grapefruit juice, grapefruit, cauliflower, red bell peppers and red
cabbage; beta carotene, from carrots, spinach, vegetable soup, endive and tomato;
and flavonoids from tea, onions, apples and carrots.

Over an average of 9.6 years of follow-up, 465 participants developed dementia; 365
of those were diagnosed with Alzheimer's disease. After adjusting for other potentially
related factors, the one-third of individuals who consumed the most vitamin E (a
median or midpoint of 18.5 milligrams per day) were 25 percent less likely to develop
dementia than the one-third of participants who consumed the least (a median of 9
milligrams per day). Dietary intake levels of vitamin C, beta carotene and flavonoids
were not associated with dementia risk. Results were similar when only the
participants diagnosed with Alzheimer's disease were assessed.

"The brain is a site of high metabolic activity, which makes it vulnerable to oxidative
damage, and slow accumulation of such damage over a lifetime may contribute to
the development of dementia," the authors write. "In particular, when beta-amyloid
(a hallmark of pathologic Alzheimer's disease) accumulates in the brain, an
inflammatory response is likely evoked that produces nitric oxide radicals and
downstream neurodegenerative effects. Vitamin E is a powerful fat-soluble
antioxidant that may help to inhibit the pathogenesis of dementia."

Future studies are needed to evaluate dietary intake of antioxidants and dietary risks,
including different points at which consuming more antioxidants might reduce risk,
the authors conclude.

More information: Arch Neurol. 2010;67[7]:819-825.

Provided by JAMA and Archives Journals

"Eating foods rich in vitamin E associated with lower dementia risk." July 12th, 2010.
www.physorg.com/news198172687.html