Effect of low dose ω-3 poly unsaturated fatty acids on cognitive status among older people: a double-blind randomized placebo-controlled study

Abstract

BackgroundCognitive 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 ω-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.MethodsIn 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.ResultsMMSE 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 ω-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 ω-3 PUFA effect except in normal cognition group, that amount of decline in AMT in ω-3 poly unsaturated fatty acids (PUFAs) was less than placebo group.ConclusionsIt seems that prescription of low dose ω-3 PUFAs for 6 months had no significant beneficial effects on improvement of cognition or prevention of cognitive decline in older people.

Dietary Regulation of Gut-Brain Axis in Alzheimer’s Disease: Importance of Microbiota Metabolites

“…Daily supplementation of omega-3 fatty acids for 6 months in the OmegAD trial improved cognitive performance in individuals with mild AD (although effects in cognitively normal individuals were less apparent) (Eriksdotter et al, 2015). Indeed, similar results are found in other studies in which dietary supplementation of omega-3 fatty acids improved cognition with the greatest effects observed in those with mild cognitive impairment or at the low end of cognitively normal (Kotani et al, 2006;Lee et al, 2013;Mahmoudi et al, 2014;Hamel et al, 2015;Andrieu et al, 2017;Soininen et al, 2017;Zhang et al, 2018). Moreover, improvements following DHA supplementation may be maintained for a period beyond the DHA treatment (Quinn et al, 2010;Yurko-Mauro et al, 2010;Zhang et al, 2016).…”

Challenges to determining whether DHA can protect against age-related cognitive decline

“…For example, most studies used fish oil as a supplementation, providing both DHA and eicosapentaenoic acid (EPA), with the latter also potentially contributing to the preventive effect of fish oil against cognitive decline. Moreover, the protective role of DHA against age-related cognitive decline may depend on APOE genotype [84] and on the degree of cognitive decline at baseline, and may be stronger in those with the mildest cognitive impairment [85][86][88][89][90][91]. This suggests that DHA may be more efficient as a preventive intervention rather than as a curative treatment.…”

Docosahexaenoic acid: one molecule diverse functions

“…Kotani et al [145] demonstrated that DHA (240 mg/day) supplementation significantly ameliorated scores of immediate memory and attention in adults with MCI, but not in the AD patients who were provided with the same dose of supplementation for the same period. One study reported no significant prevention of cognitive decline in older people with MCI given DHA over six months [146]. Lopez et al [147], in their dietary intervention study, reported that fish intake was associated with lower odds of developing AD, but this did not reach statistical significance.…”