Food | January 2008

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Fish: Great Food as We Age

In the U.S., dementia, or at the least loss of cognitive function, is becoming virtually synonymous with old age, but two recent Norwegian studies suggest it doesn't have to be, that better brain function in older adults can be promoted by a diet that includes fatty fish. In the Zutphen Elderly Study, researchers examined the associations between fish consumption, intake of the omega-3 fats DHA and EPA, and subsequent 5-year cognitive decline among 210 men aged 70-89 when the study began. Men who ate fish experienced significantly less cognitive decline than those who did not. An average difference of approximately 380 mg/day in EPA+DHA intake was associated with a 1.1-point difference in cognitive decline. (380 mg/day is an amount easily supplied in a fish-containing diet. For comparison, a 4-ounce serving of salmon provides about 1.5 grams of omega 3s.) Study authors concluded, "A moderate intake of EPA+DHA may postpone cognitive decline in elderly men." Am J Clin Nutr. 2007 Apr;85(4):1142-7.

In the Hordaland Health Study, 2,031 adults (55% women) aged 70-74, underwent a battery of cognitive tests including the Kendrick Object Learning Test, Trail Making Test (part A), modified versions of the Digit Symbol Test, Block Design, Mini-Mental State Examination, and the Controlled Oral Word Association Test.

Subjects eating an average of at least 10 grams of fish a day (1 ounce = 30 grams, so eating just 2.1 ounces of fish each week would supply an average of 10 grams daily) had significantly better mean test scores and a lower prevalence of poor cognitive performance than those whose intake averaged less than 10 grams/day. The associations between total seafood intake and cognition were strongly dose-dependent with maximum benefit observed at an intake of approximately 75 grams/day (this would translate to 2.5 ounces of fish per day or approximately four 4-ounce servings of fish per week). Almost all cognitive functions were beneficially influenced by eating fish, particularly nonprocessed lean fish and fatty fish. Am J Clin Nutr. 2007 Nov;86(5):1470-8.

van Gelder BM, Tijhuis M, Kalmijn S, Kromhout D. Fish consumption, n-3 fatty acids, and subsequent 5-y cognitive decline in elderly men: the Zutphen Elderly Study. Am J Clin Nutr. 2007 Apr;85(4):1142-7. PMID: 17413117

Nurk E, Drevon CA, Refsum H, et al. Cognitive performance among the elderly and dietary fish intake: the Hordaland Health Study. Am J Clin Nutr. 2007 Nov;86(5):1470-8. PMID: 17991661