High Folate Intake May Lower AD Risk


High intake of folate decreased the risk of Alzheimer's disease in a predominantly Hispanic and African American cohort of elderly people, according to a recently published study.

There was a statistically significant association between AD risk and combined dietary and supplemental folate consumption, but not between AD and either type of folate alone, suggesting that cumulative intake from both sources is important in assessing Alzheimer's risk, wrote Dr. Jose A. Luchsinger of Columbia University, New York, and his associates.

These results are consistent with those of several previous studies of folate and AD risk, but conflict with the results of several others. “Definitive conclusions about the value of higher folate intake in the prevention of AD cannot be made at this time,” Dr. Luchsinger and his associates said, adding that “the decision to increase folate intake to prevent AD should await clinical trials.”

In what they described as the first published study of the issue in a cohort that was predominantly black and Caribbean Hispanic, the researchers assessed diet and cognitive status in 965 subjects in 1992–1994 and thereafter at 18-month intervals.

The subjects were Medicare recipients aged 65 years and older whose folate intakes were estimated using 61-item food frequency questionnaires. The group had a high prevalence of cardiovascular disease. A total of 192 developed AD over a mean follow-up of 6 years.

The risk of AD decreased with increasing intake of folate but not of vitamins B6 or B12, the investigators said (Arch. Neurol. 2007;64:86–92).

People with AD had a total folate intake “that was almost statistically significantly lower” than that in subjects without AD.

There was a “modest” correlation between folate intake and plasma homocysteine levels, suggesting that folate's ability to lower homocysteine may account for some of its effect on AD risk, Dr. Luchsinger and his associates said.

And since folate is derived primarily from vegetable sources, folate intake may be a marker of a healthier diet or of other socioeconomic or lifestyle factors, they noted.

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