BENEFICIAL EFFECTS OF DAILY DIETARY OMEGA-3 POLYUNSATURATED FATTY ACID SUPPLEMENTATION ON AGE-RELATED COGNITIVE DECLINE IN ELDERLY JAPANESE WITH VERY MILD DEMENTIA: A 2-YEAR RANDOMIZED, DOUBLE-BLIND,
M. Hashimoto, K. Yamashita, S. Kato, T. Tamai, Y. Tanabe, M. Mitarai, I. Matsumoto, M. Ohno
J Aging Res Clin Practice 2012;1(3):193-201
Background: Studies of the effects of dietary omega-3 polyunsaturated fatty acid intake on cognitive functions in elderly Japanese are lacking. In this 2-year randomized, double-blind, placebo-controlled trial, we primarily aimed to examine the effects of daily dietary docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) supplementation on cognitive functions in healthy elderly Japanese. Methods: Independently living community dwellers aged 57 years or over (n = 111, 72.4 ± 7.7 years) were randomized to active and placebo groups. The active group consumed fish sausages containing 1720 mg DHA and 407 mg EPA daily for 24 months; the placebo group consumed fish sausages containing olive oil daily for the first 12 months and fish sausages containing DHA and EPA daily for the next 12 months. Cognitive functions were assessed by using the Revised Hasegawa's Dementia Scale (HDS-R), Mini-Mental State Examination (MMSE), and Frontal Assessment Battery (FAB) and blood biochemistry was analyzed at the baseline and 6, 12, 18, and 24 months thereafter. Results: The mean baseline HDS-R, MMSE, and FAB scores were not significantly different between the placebo and the active groups. On average, the plasma and erythrocyte plasma membrane DHA and EPA levels significantly increased in the active group at 6 and 12 months, but were not significantly different between the groups at 24 months. Further, at 6 and 12 months, the mean total HDS-R, MMSE, and FAB scores were not significantly different between the groups, but the mean changes in FAB-subitem “Conflicting instructions” scores from the baseline to month 6 and MMSE-subitem “Language: copying” scores from the baseline to month 12 were significantly greater in the active group. Depending on the responses to the MMSE, the subjects were also grouped as responders and nonresponders. The mean changes in the total MMSE scores and MMSE-subitem “Attention and Calculation” scores from the baseline to month 12 were significantly greater in the responders of the active group. Conclusion: Long-term daily dietary DHA and EPA supplementation seems to have beneficial effects against age-related cognitive decline in otherwise healthy elderly Japanese with very mild dementia.