Fat in Fish May Help Prevent Dementia
Fatty Acid DHA May Be Key to 47% Lower Dementia Risk, Researchers Report
Nov. 13, 2006 -- Eating fish three times a week may cut your odds of getting
dementia almost in half.
That news appears in the November issue of Archives of
Researchers base their findings on a study of 900 older men and women. The
scientists found that participants with the highest DHA levels at the beginning
of the study were 47% less likely to get dementia and 39% less likely to get
during the study than the rest of the group.
The researchers included Ernst Schaefer, MD, of the U.S. Department of
Agriculture Human Nutrition Research Center, at Tufts University.
DHA is short for the fatty acid docosahexaenoic. It is found in fish such as
salmon, sardines, and herring, and appears important in cutting dementia risk,
Schaefer's team notes.
The scientists don't promise DHA prevents the condition, calling instead for
The study looked at about 900 men and women, aged 55 to 88, who did not have
dementia at its start.
Participants completed dietary surveys and got their blood DHA levels
They then took mental skills tests every two years and were followed for
nine years, on average.
During that time, 99 developed dementia, including 71 who got Alzheimer's
But the participants who had had the highest DHA levels on the earlier tests
were much less likely to get either condition. Those with the highest DHA
levels reported eating fish three times weekly, on average.
The results take other factors -- including age and education level -- into
However, they don't prove DHA prevents dementia. This study was purely
observational; the scientists didn't directly test DHA for dementia
The study is the "first evidence" of a link between direct measures
of human blood DHA levels and lower Alzheimer's disease risk, writes
editorialist Martha Clare Morris, ScD.
DHA is abundant in the healthy human brain, notes Morris, who works at
Chicago's Rush University Medical Center.
Fish is the main dietary source of DHA, but vegetable oil, soybeans,
walnuts, wheat germ, and human milk also contain DHA, Morris notes. It is also
available in supplements.
Future studies should check whether such supplements can halt the worsening
of established dementia, say the researchers, and Morris agrees supplements
deserve further study.