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J Alzheimers Dis. 2016;50(2):547-57. doi: 10.3233/JAD-150777.

Omega-3 Fatty Acid Status Enhances the Prevention of Cognitive Decline by B Vitamins in Mild Cognitive Impairment.

Author information

1
Institute of Public Health, College of Medicine and Health Sciences, United Arab Emirates University, United Arab Emirates.
2
OPTIMA, Department of Pharmacology, University of Oxford, Oxford, UK.
3
Department of Nutrition, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, Oslo, Norway.
4
Division of Geriatric Medicine, Department of Medicine, Faculty of Health Sciences, University of Cape Town, South Africa.

Abstract

A randomized trial (VITACOG) in people with mild cognitive impairment (MCI) found that B vitamin treatment to lower homocysteine slowed the rate of cognitive and clinical decline. We have used data from this trial to see whether baseline omega-3 fatty acid status interacts with the effects of B vitamin treatment. 266 participants with MCI aged ≥70 years were randomized to B vitamins (folic acid, vitamins B6 and B12) or placebo for 2 years. Baseline cognitive test performance, clinical dementia rating (CDR) scale, and plasma concentrations of total homocysteine, total docosahexaenoic and eicosapentaenoic acids (omega-3 fatty acids) were measured. Final scores for verbal delayed recall, global cognition, and CDR sum-of-boxes were better in the B vitamin-treated group according to increasing baseline concentrations of omega-3 fatty acids, whereas scores in the placebo group were similar across these concentrations. Among those with good omega-3 status, 33% of those on B vitamin treatment had global CDR scores >0 compared with 59% among those on placebo. For all three outcome measures, higher concentrations of docosahexaenoic acid alone significantly enhanced the cognitive effects of B vitamins, while eicosapentaenoic acid appeared less effective. When omega-3 fatty acid concentrations are low, B vitamin treatment has no effect on cognitive decline in MCI, but when omega-3 levels are in the upper normal range, B vitamins interact to slow cognitive decline. A clinical trial of B vitamins combined with omega-3 fatty acids is needed to see whether it is possible to slow the conversion from MCI to AD.

KEYWORDS:

Alzheimer’s disease; B vitamins; clinical dementia rating scale; cognition; omega–3 fatty acids

PMID:
26757190
PMCID:
PMC4927899
DOI:
10.3233/JAD-150777
[Indexed for MEDLINE]
Free PMC Article

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