[PHNUTR-L] Folates more effective in limiting Alzheimer's disease risk than antioxidants, other nutrients

[Kathrynne Holden, MS, RD]

Colleagues, the following is FYI and does not necessarily reflect my own
opinion. I have no further knowledge of the topic.
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Public release date: 12-Aug-2005
http://www.eurekalert.org/pub_releases/2005-08/uoc--fme081105.php

Contact: Tom Vasich
tmvasich at uci.edu
949-824-6455
University of California - Irvine

Folates more effective in limiting Alzheimer's disease risk than 
antioxidants, other nutrients

Major observational study points to importance of healthy diet for 
long-term brain health

Irvine, Calif. -- Adults who eat the daily recommended allowance of 
folates -- B-vitamin nutrients found in oranges, legumes, leafy green 
vegetables and folic acid supplements -- significantly reduce their risk 
of developing Alzheimer's disease, according to results from a long-term 
National Institute on Aging study of diet and brain aging.

The study also found that folates appear to have more impact on reducing 
Alzheimer's risk than vitamin E, a noted antioxidant, and other 
nutrients considered for their effect as a brain-aging deterrent.

Maria Corrada and Dr. Claudia Kawas of UC Irvine's Institute for Brain 
Aging and Dementia led the effort, which analyzed the diets of 
non-demented men and women age 60 and older. They compared the food 
nutrient and supplement intake of those who later developed Alzheimer's 
disease to the intake of those who did not develop the disease. It is 
the largest study to date to report on the association between folate 
intake and Alzheimer's risk and to analyze antioxidants and B vitamins 
simultaneously.

Results appear in the inaugural issue of the quarterly peer-reviewed 
research journal, Alzheimer's & Dementia: The Journal of the Alzheimer's 
Association.

"Although folates appear to be more beneficial than other nutrients, the 
primary message should be that overall healthy diets seem to have an 
impact on limiting Alzheimer's disease risk," said Corrada, who like 
Kawas started with the study while at Johns Hopkins University in Baltimore.

The researchers used data from the Baltimore Longitudinal Study of Aging 
to identify the relationship between dietary factors and Alzheimer's 
disease risk. Between 1984 and 1991, study volunteers provided detailed 
dietary diaries, which included supplement intake and calorie amounts, 
for a typical seven-day period.

Ultimately, 57 of the original 579 participants developed Alzheimer's 
disease. But the researchers found that those with higher intake of 
folates, vitamin E and vitamin B6 shared lower comparative rates of the 
disease. And when the three vitamins were analyzed together, only 
folates were associated with a significantly decreased risk.

In turn, no association was found between vitamin C, carotenoids (such 
as beta-carotene) or vitamin B-12 intake and decreased Alzheimer's risk.

"The participants who had intakes at or above the 400-microgram 
recommended dietary allowance of folates had a 55-percent reduction in 
risk of developing Alzheimer's," said Corrada, an assistant professor of 
neurology. "But most people who reached that level did so by taking 
folic acid supplements, which suggests that many people do not get the 
recommended amounts of folates in their diets."

Folates have already been proven to reduce birth defects, and research 
suggests that they are beneficial to warding off heart disease and 
strokes. Although folates are abundant in foods such as liver, kidneys, 
yeast, fruits (like bananas and oranges), leafy vegetables, whole-wheat 
bread, lima beans, eggs and milk, they are often destroyed by cooking or 
processing. Because of their link to reducing birth defects, folates 
have been added to grain products sold in the U.S. since 1998. But even 
with this supplement, it is thought that many Americans have 
folate-deficient diets.

Recent research is beginning to show relationships between folates and 
brain aging. Earlier this year, Dutch scientists showed that adults who 
took 800 micrograms of folic acid daily had significant improved memory 
test scores, giving evidence that folates can slow cognitive decline.

"Given the observational nature of this study, it is still possible that 
other unmeasured factors also may be responsible for this reduction in 
risk," said Kawas, the Al and Trish Nichols Chair in Clinical 
Neuroscience. "People with a high intake of one nutrient are likely to 
have a high intake of several other nutrients and may generally have a 
healthy lifestyle. But further research and clinical studies on this 
subject will be necessary."

Judith Hallfrisch of the U.S. Department of Agriculture, Denis Muller 
with the National Institute on Aging and Ron Brookmeyer with Johns 
Hopkins collaborated on the study, which was originally undertaken at 
the Gerontology Research Center of the NIA and the Department of 
Neurology at Johns Hopkins. Study funding came from the Extramural 
Programs of the NIA.

Begun in 1958 by the NIA, the Baltimore Longitudinal Study of Aging is 
America's longest-running scientific study of human aging. BLSA 
scientists are learning what happens as people age and how to sort out 
changes due to aging from those due to disease or other causes. More 
than 1,400 men and women are study volunteers. For more information, 
see: www.grc.nia.nih.gov/branches/blsa/blsa.htm.
-- 
Kathrynne Holden, MS, RD < fivestar at nutritionucanlivewith.com >
"Ask the Parkinson Dietitian"  http://www.parkinson.org/
"Eat well, stay well with Parkinson's disease"
"Parkinson's disease: Guidelines for Medical Nutrition Therapy"
http://www.nutritionucanlivewith.com/