Eating fish associated with slower cognitive decline
Consuming fish at least once a week was associated with a 10% per year slower rate of cognitive decline in elderly people, according to a new study in the December 2005 issue of Archives of Neurology, one of the JAMA/Archives journals.
Fish is a direct source of omega-3 fatty acids, which have been shown to be essential for neurocognitive development and normal brain functioning, according to background information in the article. Fish consumption has been associated with lower risk of dementia and stroke and recent studies have suggested that consumption of one omega-3 fatty acid in particular, docosahexaenoic acid (DHA), is important for memory performance in aged animals.
Martha Clare Morris, Sc.D., of Rush University Medical Center, Chicago, and colleagues analyzed six years of data from an ongoing study of Chicago residents, 65 years and older, first interviewed between 1993 and 1997 and every three years in two follow-up interviews. Interviews included four standardized cognitive tests and dietary questions on the frequency of consumption of 139 different foods, as well as questions of daily activities, exercise levels, alcohol consumption and medical history.
The researchers reported "The rate of cognitive decline was reduced by 10% to 13% per year among persons who consumed one or more fish meals per week compared with those with less than weekly consumption. The rate reduction is the equivalent of being three to four years younger in age."
The researchers examined whether overall dietary consumption patterns accounted for the association of cognitive decline and fish consumption, but the rate differences did not change after adjusting for consumption of fruit and vegetables.
"Cognitive decline is common among older people and is very much associated with advancing age," the authors write. "Our data offer no insight as to whether this cognitive decline is pathological or the result of a normal aging process. Nonetheless, data from the United States and other countries indicate that it is a widespread and increasing public health problem."
"This study suggests that eating one or more fish meals per week may protect against cognitive decline associated with older age," the authors conclude. "More precise studies of the different dietary constituents of fish should help to understand the nature of the association." "It's a good bet that eating fish also could boost cognitive abilities of people younger than 65, although this hasn't been proven", Morris said.
Arch Neurol. 2005; 62: 1-5.