Nutrition is an important modifiable risk factor that plays a role in the strategy to prevent or delay the onset of dementia. Research on nutritional

High intake of n-3 polyunsaturated fatty acids may protect against age-related cognitive decline. However, results from epidemiologic studies are inconclusive, and results from randomized trials in elderly subjects without dementia are lacking. To investigate the effect of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) supplementation on cognitive performance. Double-blind, placebo-controlled trial involving 302 cognitively healthy (Mini-Mental State Examination score > 21) individuals aged 65 years or older. Participants were randomly assigned to 1,800 mg/d EPA-DHA, 400 mg/d EPA-DHA, or placebo capsules for 26 weeks. Cognitive performance was assessed using an extensive neuropsychological test battery that included the cognitive domains of attention, sensorimotor speed, memory, and executive function. The mean age of the participants was 70 years, and 55% were male. Plasma concentrations of EPA-DHA increased by 238% in the high-dose and 51% in the low-dose fish oil group compared with placebo, reflecting excellent compliance. Baseline scores on the cognitive tests were comparable in the three groups. Overall, there were no significant differential changes in any of the cognitive domains for either low-dose or high-dose fish oil supplementation compared with placebo. In this randomized, double-blind, placebo-controlled trial, we observed no overall effect of 26 weeks of eicosapentaenoic acid and docosahexaenoic acid supplementation on cognitive performance.

Background: It is suggested that a low intake of fish and/or n−3 PUFA is associated with depressed mood. However, results from epidemiologic studies are mixed, and randomized trials have mainly been performed in depressed patients, yielding conflicting results. Objective: We investigated the effect of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) on mental well-being in a double-blind, placebo-controlled trial. Design: Independently living individuals (n = 302) aged ≥65 y were randomly assigned to consume 1800 mg/d EPA+DHA, 400 mg/d EPA+DHA, or placebo capsules for 26 wk. Changes in mental well-being were assessed as the primary outcome with the Center for Epidemiologic Studies Depression Scale (CES-D), Montgomery-Åsberg Rating Scale (MADRS), Geriatric Depression Scale (GDS-15), and Hospital Anxiety and Depression Scale (HADS-A). Results: Plasma concentrations of EPA+DHA increased by 238% in the high-dose and 51% in the low-dose fish-oil group compared with the placebo group, reflecting excellent compliance. Baseline CES-D scores ranged from 5.9 to 6.8 in the 3 groups and were not significantly different between groups. Mean changes in CES-D scores after 26 wk were −0.2, 0.2, and −0.4 (P = 0.87) in the high-dose fish oil, low-dose fish oil, and placebo groups, respectively. Treatment with neither 1800 mg nor 400 mg EPA+DHA differentially affected any of the measures of mental well-being after 13 or 26 wk of intervention compared with placebo. Conclusions: In this randomized, double-blind, placebo-controlled trial we observed no effect of EPA+DHA supplementation for 26 wk on mental well-being in the general older population studied. This trial was registered at clinicaltrials.gov as NCT00124852.

Objective: To examine the association between consumption of seafood and long-chain n-3 fatty acids with change in 5 cognitive domains over an average of 4.9 years. Methods: From an ongoing longitudinal, community-based epidemiologic study of aging and dementia (the Rush Memory and Aging Project), we included 915 participants (age 81.4 ± 7.2 years, 25% men) who had completed at least one follow-up cognitive assessment and dietary data. Diet was assessed by semiquantitative food frequency questionnaire. Scores for global cognitive function and 5 cognitive domains (episodic, semantic, and working memory, perceptual speed, and visuospatial ability) were assessed using 19 cognitive tests. Mixed models adjusted for multiple risk factors of cognitive change were used to assess the associations. Results: Consumption of seafood was associated with slower decline in semantic memory (β = 0.024; p = 0.03) and perceptual speed (β = 0.020; p = 0.05) in separate models adjusted for age, sex, education, participation in cognitive activities, physical activity, alcohol consumption, smoking, and total energy intake. In secondary analyses, APOE ε4 carriers demonstrated slower rates of decline in global cognition and in multiple cognitive domains with weekly seafood consumption and with moderate to high long-chain n-3 fatty acid intake from food. These associations were not present in APOE ε4 noncarriers. Higher intake levels of α-linolenic acid were associated with slower global cognitive decline, but also only in APOE ε4 carriers. Conclusions: These results suggest protective relations of one meal per week of seafood and long-chain n-3 fatty acids against decline in multiple cognitive domains. The role of APOE ε4 in this association needs further study.

Dietary modulation of the gastro-intestinal microbiota is a potential target in improving healthy ageing and age-related functional outcomes, including cognitive decline. We explored the association between diet, gastro-intestinal microbiota and cognition in Dutch healthy older adults of the ‘New dietary strategies addressing the specific needs of the elderly population for healthy aging in Europe’ (NU-AGE) study. The microbiota profile of 452 fecal samples from 226 subjects was determined using a 16S ribosomal RNA gene-targeted microarray. Dietary intake was assessed by 7-day food records. Cognitive functioning was measured with an extensive cognitive test battery. We observed a dietary and microbial pro- to anti-inflammatory gradient associated with diets richer in animal- or plant-based foods. Fresh fruits, nuts, seeds and peanuts, red and processed meat and grain products were most strongly associated to microbiota composition. Plant-rich diets containing fresh fruits, nuts, seeds and peanuts were positively correlated with alpha-diversity, various taxa from the Bacteroidetes phylum and anti-inflammatory species, including those related to Faecalibacterium prausnitzii and Eubacterium rectale and E. biforme. Animal product-rich diets associated with pro-inflammatory species, including those related to Ruminococcus gnavus and Collinsella spp.. Cognition was neither associated with microbiota composition nor alpha-diversity. In conclusion, diets richer in animal- and plant-based foods were related to a pro- and anti-inflammatory microbial profile, while cognition was associated with neither.