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Vitamins D and E May Affect Dementia Risk

Studies Show Blood Levels of Vitamins D and E Are Linked to Risk of Cognitive Decline

Can Vitamin D Prevent Dementia? continued...

"At present, there is not rigorous evidence for health benefits of vitamin D supplementation in community-dwelling individuals, beyond avoiding the very low levels," he says. The bottom line? "Routine supplementation of vitamin D is not, at present, justified."

Michael Holick, MD, PhD, is not as cautious in his interpretation of the new findings or in his vitamin D recommendations. As a professor of medicine, physiology, and biophysics at the Boston University School of Medicine and the director of the Vitamin D, Skin, and Bone Research Laboratory there, Holick has been warning Americans about the dangers of vitamin D deficiency for most of his career.

"I am not at all surprised that vitamin D deficiency is associated with cognitive decline," he tells WebMD. His advice is simple: "Take more vitamin D. All adults should consume 2,000 international units (IU) of vitamin D per day."

Currently, the dietary reference intake (DRI) for vitamin D is 200 IU per day for adults aged 14 to 50, 400 IU per day for adults 50 to 71, and 600 IU per day for those older than 71. The Institute of Medicine is considering new recommendations for vitamin D intake.

But the jury is in, according to Holick, and the time to supplement is before you develop signs of dementia or other diseases. "The role of vitamin D is to prevent and reduce risk of disease more so than treat them," he says.

Vitamin E and Alzheimer's Risk

A second study in the July issue of the Archives of Neurology shows that eating foods rich in vitamin E may help lower risks of developing dementia and Alzheimer's disease.

Vitamin E can be found in whole grains, wheat germ, leafy green vegetables, sardines, egg yolks, nuts and seeds, but most participants in the new study got their vitamin E from margarine, sunflower oil, butter, cooking fat, soybean oil, and mayonnaise. Antioxidants like vitamin E protect the body from damage caused by harmful molecules called free radicals.

In the study of 5,395 people aged 55 and older, those who got the most vitamin E in their diet -- 18.5 milligrams per day, on average -- were 25% less likely to develop dementia than their counterparts who got the least vitamin E on their diet, about 9 milligrams per day. 

Elizabeth R. Devore ScD, of Erasmus Medical Center in Rotterdam, Netherlands, and colleagues followed the study participants for 9.6 years. During this time, 465 developed dementia, including 365 cases of Alzheimer's disease. They also looked at how much vitamin C, beta-carotene, and flavonoids participants consumed, but only dietary vitamin E seemed to be related to dementia risk.

More Study Needed

Mary Sano, PhD, the director of the Alzheimer Disease Research Center and a professor of psychiatry at the Mount Sinai School of Medicine in New York City, says that more study is needed before any recommendations can be made about vitamin D or vitamin E and dementia risk.

"There is no assurance that raising the levels of vitamin D would reduce the association with cognitive decline," she tells WebMD in an email. "This report should not lead us to vitamin supplementation for everyone, but if one's levels are severely low then supplementation may be warranted for many reasons, not just dementia."

As far as eating more vitamin E-rich foods to reduce risk of Alzheimer's disease, Sano says other factors may be at play; meaning that it may not be the E per se as much as the fact that people who eat diets that are rich in vitamin E and other antioxidants may eat less fat and sugar.  She also cautions that the benefits were seen from whole foods, not supplements.

"The importance of this study is that it suggests that dietary factors, particularly shifting food intakes from one food group to perhaps a healthier one, may have benefit, but many of the supplementation studies have not shown that you can reverse the effects of diet by taking vitamins," she says.

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