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-3fattyacidstatus interacts with the effects of Bvitamin treatment.
266 participants with MCI aged ≥70 years were randomized to Bvitamins (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-3fatty 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-3fatty acids, whereas scores in the placebo group were similar across these concentrations.
Among those with good omega-3status, 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 Bvitamins, while eicosapentaenoic acid appeared less effective.
When omega-3fattyacidconcentrations are low, B vitamin treatment has no effect on cognitivedecline in MCI, but when omega-3 levels are in the upper normal range, B vitamins interact to slow cognitivedecline. A clinical trial of Bvitamins combined with omega-3fatty acids is needed to see whether it is possible to slow the conversion from MCI to AD.
FAB RESEARCH COMMENT:
Findings from this 2-year clinical trial (the Oxford Vitacog Study) have already shown benefits in older adults with Mild Cognitive Impairment from dietary supplementation with Vitamins B6, B12 and folate for:
This new study reveals that the protective effect of B vitamins on cognitive decline and dementia depended on omega-3 status. Only those participants with medium or highest plasma omega-3 levels showed reduced cognitive and clinical decline. Those with the lowest omega-3 did not benefit from the B vitamins.
These findings mirror those from an earlier study, showing that physical brain shrinkage following B vitamin supplementation also depended on good omega-3 status. (Jernerén et al., 2015)
For a summary of this research, see the associated news article here: