Does Beta-Carotene Preserve Memory?
Study Shows Supplements May Help Keep Thinking Skills Sharp
"We found [in] the men who had been on beta-carotene long term -- 18
years [on average] -- their memory was significantly better than the placebo
group," Grodstein says. In the 18-month interval between studies, she says,
some of the men in the original study may have stopped the beta-carotene
Grodstein says she would categorize that improvement as modest. Even so, she
says, modest improvement may lead to substantial differences in a person's
eventual risk of getting dementia. Taking the supplements short term had no
effect, she says.
The study is published in the Nov. 12 issue of Archives of Internal
Medicine. The research was supported by grants from the National Institutes
of Health, BASF Corp. (which makes a beta-carotene supplement), and others.
The unusual study design, in which some participants were carried over from
the other study and kept their original assignments, may have affected the
results, says Peifeng Hu, MD, staff geriatrician at Santa Monica-UCLA Medical
Center & Orthopaedic Hospital, Calif. Hu is also assistant professor
of geriatric medicine at the University of California Los Angeles David Geffen
School of Medicine.
The findings don't warrant recommending supplements of beta-carotene, he
says. "I would not change my practice based on this study," says Hu,
who found in his own research that high blood levels of beta-carotene (not
necessarily from supplements) reduced the risk of cognitive decline in people
genetically predisposed to get Alzheimer's. His study findings were published
in 2006 in the Journal of Gerontology.
Hu says the area is worthy of more study but points out that the evidence so
far is conflicting: "There have been randomized clinical trials that have
demonstrated the potential harm resulting from beta-carotene supplementation in
In an editorial accompanying the study, Kristine Yaffe, MD, a researcher at
the San Francisco VA Medical Center and University of California, San
Francisco, also calls for caution. She references several other studies in
which beta-carotene and other antioxidants have had little or no effect on
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"It's good to be cautious," says Grodstein.
Although the effect of the supplements was modest, she notes that the
benefits she found were greater than what was observed in another study in
which Aricept, a drug commonly used to treat the symptoms of Alzheimer's, was
given to healthy people to test its effect on cognitive function.