Study: Combination of Vitamin E and C Supplements in Higher Doses May Reduce Alzheimer's Risk

Regular use of high-dose vitamin E and C supplements in combination may reduce the risk of Alzheimer's disease, according to a study reported in the January issue of the Archives of Neurology.

Antioxidant vitamin supplements such as E and C may be an ideal prevention strategy for people as they age since they are relatively nontoxic and are thought to have wide-ranging health benefits, according to the researchers.

The researchers examined data from a large study to determine the prevalence and incidence of Alzheimer's disease and other dementias in people 65 or older. Study participants were asked about their vitamin usage. The researchers then compared the subsequent risk of developing Alzheimer's disease among supplement users versus nonusers.

About 17 percent of the study participants reported taking vitamin E or C supplements. These individuals were significantly more likely to be female, younger, better educated and reported better general health when compared to non-supplement users. In addition to those who took vitamin supplements, another 20 percent of study participants used multivitamins, but without a high dosage of vitamin E or C.

The researchers found that those who took vitamin E and C supplements had a reduced risk of developing Alzheimer's disease even after controlling for age, sex, education and general health. However, there was no notable reduction in the risk of Alzheimer's disease with vitamin E or vitamin C alone or with multivitamins.

According to the researchers, multivitamins typically contain the recommended daily allowance of vitamin E (22 international units or 15 milligrams) and vitamin C (75-90 milligrams), while individual supplements contain up to 1,000 international units of vitamin E and 500-1,000 milligrams or more of vitamin C.

The researchers explained that the use of vitamins E and C may offer protection against Alzheimer's disease when taken together in the higher doses available in individual supplements. In addition, there may be some protective effect with vitamin E when it is combined with the lower doses of vitamin C found in multivitamins, they noted.

Study author Peter P. Zandi, an assistant professor at John's Hopkins Bloomberg School of Public Health, said further study is needed before any firm conclusions about the protective effects of these antioxidants can be drawn.

"Such trials should consider testing a regimen of vitamin E and C in combination," Zandi said. "If effective, the use of these antioxidant vitamins may offer an attractive strategy for the prevention of Alzheimer's disease."

Johns Hopkins Bloomberg School of Public Health