Review Supports Higher Intakes of DHA Omega-3 Associated with Lower Risk of Dementia and Alzheimer Disease in Elderly
Zhang, Y. et al., Amer. J. Clinical Nutrition, in press, 2016
Dept. of Food Science and Nutrition, Zhejiang University, Hangzhou, China
Published studies have reported on the benefits of DHA/EPA intakes in preventing cognitive disorders amongst the elderly although inconsistent findings have led to some confusion amongst the media/press and the public. Thus, the present review (meta-analysis) of previously-published research investigations aimed to systematically investigate associations between fish and long-chain omega-3 intakes in relation to mild-to-severe cognitive impairment risk amongst the aging population.
For this purpose, a total of 21 previously-published studies were included for analyses involving a total of 181,580 subjects from which a total of 4438 cases (263 of mild cognitive impairment (MCI) plus 320 cases of cognitive decline plus 1864 cases of dementia plus 1332 cases of Alzheimer disease (AD) plus 659 cases of Parkinson disease (PD)) were identified during a follow-up period of 2.1-21 years). The overall findings indicated that a 1-serving per week increment of dietary fish was associated with a 5 % and 7 % lower risk of dementia and AD, respectively. Furthermore, each 0.1 gram/day increment in dietary DHA omega-3 intake was associated with a 14 % and 39 % lower risk of dementia and AD, respectively, but not for PD. Each 0.05 gram increment in EPA intake showed no significant benefit for the risk of AD or PD.
The present meta-analysis supports overall recommendations from various national and international organizations to increase fish/seafood and long-chain omega-3 intakes for health and disease prevention. Fishery products were found again herein to be associated with a lower risk of cognitive impairment and DHA with a lower risk of dementia and AD. However, the specific targets for higher intakes of fish and/or DHA (from various food sources and via supplementation) so as to maximize protection against cognitive impairment in the aging population remain to be established.