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.
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ABSTRACT: n-3 PUFAs play an important role in cognitive function. The objective was to investigate the effect of n-3 PUFA supplements on cognitive development, function, and decline throughout the life span. The study included randomized controlled trials and provided ≥3 mo of treatment. Potential studies were independently screened in duplicate, and study characteristics and outcomes were extracted. A meta-analysis was performed by using fixed- or random-effects models. The results are presented as standardized mean differences (SMDs) with 95% CIs. Of the 3692 citations retrieved, 34 studies of a total of 12,999 participants (1031 infants, 1517 children, 3657 adults, and 6794 elderly individuals) were included. Compared with placebo, n-3 PUFA supplements significantly improved cognitive development in infants, including the Mental Development Index (SMD: 0.33; 95% CI: 0.15, 0.52), the Psychomotor Development Index (0.27; 95% CI: 0.09, 0.45), and language (0.27; 95% CI: 0.13, 0.42), motor (0.29; 95% CI: 0.14, 0.43), and cognitive (0.31; 95% CI: 0.16, 0.45) abilities. However, n-3 PUFAs did not promote cognitive function in terms of composite memory, executive function, and processing speed domains in children, adults, or the elderly, except for the attention domain. No association was found between n-3 PUFA intake and improvements in cognitive performance in terms of recognition, immediate and delayed word recall, digit span backward and forward tests, rapid visual information processing, verbal fluency, and simple and choice reaction times. In addition, n-3 PUFA supplements were not associated with improvements in cognitive decline or with any effects on Alzheimer disease in elderly people. n-3 PUFA supplements may significantly improve cognitive development in infants but do not improve cognitive performance in children, adults, or the elderly. n-3 PUFA intake, especially that of DHA supplements, may benefit cognitive development during infancy. © 2014 American Society for Nutrition.American Journal of Clinical Nutrition 12/2014; 100(6):1422-36. DOI:10.3945/ajcn.114.095315 · 6.50 Impact Factor
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ABSTRACT: Research indicates that the chronic consumption of flavonoids is associated with cognitive benefits in adults with mild cognitive impairment and neurodegenerative disease, although to our knowledge, there have been no such studies in healthy older adults. Furthermore, the effects of commonly consumed orange juice flavanones on cognitive function remain unexplored. We investigated whether 8 wk of daily flavanone-rich orange juice consumption was beneficial for cognitive function in healthy older adults. High-flavanone (305 mg) 100% orange juice and an equicaloric low-flavanone (37 mg) orange-flavored cordial (500 mL) were consumed daily for 8 wk by 37 healthy older adults (mean age: 67 y) according to a crossover, double-blind, randomized design separated by a 4-wk washout. Cognitive function, mood, and blood pressure were assessed at baseline and follow-up by using standardized validated tests. Global cognitive function was significantly better after 8-wk consumption of flavanone-rich juice than after 8-wk consumption of the low-flavanone control. No significant effects on mood or blood pressure were observed. Chronic daily consumption of flavanone-rich 100% orange juice over 8 wk is beneficial for cognitive function in healthy older adults. The potential for flavanone-rich foods and drinks to attenuate cognitive decline in aging and the mechanisms that underlie these effects should be investigated. This trial was registered at clinicaltrials.gov as NCT01312610. © 2015 American Society for Nutrition.American Journal of Clinical Nutrition 03/2015; 101(3):506-14. DOI:10.3945/ajcn.114.088518 · 6.50 Impact Factor
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ABSTRACT: Objective: Fish oils and multivitamins are two of the most commonly used dietary supplements. Fish oil use may reduce vascular risk factors associated with cognitive decline, thus providing benefits to both heart and brain health. Multivitamins may also have direct effects on brain function. The present study investigated the effects of fish oil, with and without the addition of a multivitamin, on cognitive and cardiovascular function. Methods: In a randomized, placebo-controlled, double-blind fashion, 160 healthy adults aged 50-70 years were randomized to receive either 3 g of fish oil (240 mg eicosapentaenoic acid [EPA] + 240 mg docosahexaenoic acid [DHA]) with a multivitamin, 6 g of fish oil (480 mg EPA + 480 mg DHA) with a multivitamin, or 6 g of fish oil without a multivitamin or a placebo. Cognitive performance, brachial blood pressure, and aortic (central) blood pressure were measured at baseline, 6 weeks, and 16 weeks. Results: Treatment allocation had no effect on the primary cognitive outcomes at endpoint. Absolute increases in the red blood cell omega-3/6 ratio were associated with improvements in spatial working memory. The group receiving 6 g fish oil without the multivitamin displayed a significant decrease in aortic pulse pressure and aortic augmentation pressure, two measures of aortic blood pressure and aortic stiffness. Conclusions: Fish oil decreased aortic pulse pressure and augmentation pressure. Reductions in aortic blood pressure were not accompanied by consistent improvements in cognition.Journal of the American College of Nutrition 01/2015; 34(1):1-11. DOI:10.1080/07315724.2014.880660 · 1.68 Impact Factor