Effect of 2-y n-3 long-chain polyunsaturated fatty acid supplementation on cognitive function in older people: a randomized, double-blind, controlled trial.
ABSTRACT Increased consumption of n-3 (omega-3) long-chain polyunsaturated fatty acids (LC PUFAs), especially eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), may maintain cognitive function in later life.
We tested the hypothesis that n-3 LC PUFA supplementation would benefit cognitive function in cognitively healthy older people.
At total of 867 cognitively healthy adults, aged 70-79 y, from 20 general practices in England and Wales were randomly assigned into a double-blind controlled trial of daily capsules providing 200 mg EPA plus 500 mg DHA or olive oil for 24 mo. Treatment-allocation codes were obtained from a central computerized randomization service. Trained research nurses administered a battery of cognitive tests, including the primary outcome, the California Verbal Learning Test (CVLT), at baseline and 24 mo. Intention-to-treat analysis of covariance, with adjustment for baseline cognitive scores, age, sex, and age at leaving full-time education, included 748 (86%) individuals who completed the study.
The mean age of participants was 75 y; 55% of the participants were men. Withdrawals and deaths were similar in active (n = 49 and n = 9, respectively) and placebo (n = 53 and n = 8, respectively) arms. Mean (+/-SD) serum EPA and DHA concentrations were significantly higher in the active arm than in the placebo arm at 24 mo (49.9 +/- 2.7 mg EPA/L in the active arm compared with 39.1 +/- 3.1 mg EPA/L in the placebo arm; 95.6 +/- 3.1 mg DHA/L in the active arm compared with 70.7 +/- 2.9 mg DHA/L in the placebo arm). There was no change in cognitive function scores over 24 mo, and intention-to-treat analysis showed no significant differences between trial arms at 24 mo in the CVLT or any secondary cognitive outcome.
Cognitive function did not decline in either study arm over 24 mo. The lack of decline in the control arm and the relatively short intervention period may have limited our ability to detect any potential beneficial effect of fish oil on cognitive function in this study. The Older People And n-3 Long-chain polyunsaturated fatty acids (OPAL) Study was registered at www.controlled-trials.com as ISRCTN 72331636.
- SourceAvailable from: Neda Mehrdad[Show abstract] [Hide abstract]
ABSTRACT: Cognitive impairment is a prevalent health problem in older people and its global prevalence tends to increase parallel to the extended life expectancy in world. The beneficial effect of omega-3 PUFAs on cognitive impairment has been demonstrated in some experimental and cohort studies. In this study we aimed to assess the effect of low dose docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) supplementation on cognitive status in the elderly. In a double-blind, randomized placebo-controlled study, 199 individuals aged >=65 years with normal or mild to moderate cognition impairment were assigned to receive either 180 mg of DHA plus 120 mg of EPA or placebo for 180 days. Cognitive status was assessed using Mini-Mental State Examination (MMSE) and Abbreviated Mental Test (AMT) score. MMSE and AMT scores were not different at the time of allocation [18.84 (5.37), 18.55 (5.12), (P = 0.70) and 4.81 (2.79) and 4.64 (2.77), (P = 0.67) respectively] and over 6 months between the omega-3 PUFA- and placebo- treated groups [18.57 (5.21), 18.39 (5.10), (P = 0.80) and 4.64 (2.77) and 4.48 (2.69) and (P = 0.67)]. The participants were categorized based on MMSE score into normal cognition, mild and moderate cognitive impairment. After multivariate adjustment, there was no significant difference among categorized groups regarding the omega-3 PUFA effect except in normal cognition group, that amount of decline in AMT in omega-3 poly unsaturated fatty acids (PUFAs) was less than placebo group. It seems that prescription of low dose omega-3 PUFAs for 6 months had no significant beneficial effects on improvement of cognition or prevention of cognitive decline in older people.Journal of diabetes and metabolic disorders. 02/2014; 13(1):34.
- [Show abstract] [Hide abstract]
ABSTRACT: This review is an output of the International Life Sciences Institute (ILSI) Europe Marker Initiative, which aims to identify evidence-based criteria for selecting adequate measures of nutrient effects on health through comprehensive literature review. Experts in cognitive and nutrition sciences examined the applicability of these proposed criteria to the field of cognition with respect to the various cognitive domains usually assessed to reflect brain or neurological function. This review covers cognitive domains important in the assessment of neuronal integrity and function, commonly used tests and their state of validation, and the application of the measures to studies of nutrition and nutritional intervention trials. The aim is to identify domain-specific cognitive tests that are sensitive to nutrient interventions and from which guidance can be provided to aid the application of selection criteria for choosing the most suitable tests for proposed nutritional intervention studies using cognitive outcomes. The material in this review serves as a background and guidance document for nutritionists, neuropsychologists, psychiatrists, and neurologists interested in assessing mental health in terms of cognitive test performance and for scientists intending to test the effects of food or food components on cognitive function.Nutrition Reviews 02/2014; · 4.60 Impact Factor
- [Show abstract] [Hide abstract]
ABSTRACT: The current study aimed to investigate the effects of eicosapentaenoic acid (EPA)-rich and docosahexaenoic acid (DHA)-rich supplementations on cognitive performance and functional brain activation. A double-blind, counterbalanced, crossover design, with a 30-day washout period between two supplementation periods (EPA-rich and DHA-rich) was employed. Functional magnetic resonance imaging scans were obtained during performance of Stroop and Spatial Working Memory tasks prior to supplementation and after each 30-day supplementation period. Both supplementations resulted in reduced ratio of arachidonic acid to EPA levels. Following the EPA-rich supplementation, there was a reduction in functional activation in the left anterior cingulate cortex and an increase in activation in the right precentral gyrus coupled with a reduction in reaction times on the colour-word Stroop task. By contrast, the DHA-rich supplementation led to a significant increase in functional activation in the right precentral gyrus during the Stroop and Spatial Working Memory tasks, but there was no change in behavioural performance. By extending the theory of neural efficiency to the within-subject neurocognitive effects of supplementation, we concluded that following the EPA-rich supplementation, participants' brains worked 'less hard' and achieved a better cognitive performance than prior to supplementation. Conversely, the increase in functional activation and lack of improvement in time or accuracy of cognitive performance following DHA-rich supplementation may indicate that DHA-rich supplementation is less effective than EPA-rich supplementation in enhancing neurocognitive functioning after a 30-day supplementation period in the same group of individuals. Copyright © 2014 John Wiley & Sons, Ltd.Human Psychopharmacology Clinical and Experimental 01/2014; · 2.10 Impact Factor