Status of Vitamins B-12 and B-6 but Not of Folate, Homocysteine, and the Methylenetetrahydrofolate Reductase C677T Polymorphism Are Associated with Impaired Cognition and Depression in Adults

Abstract

The C677T polymorphism of the methylenetetrahydrofolate reductase (MTHFR) gene differs in frequency in various ethnic groups that have differing prevalence of age-related cognitive impairments. We used a series of neuro-psychological tests to examine the association of the MTHFR C677T polymorphism with cognition and depression and also to assess whether genotype modifies the association of folate and homocysteine with these outcomes. This study analyzed pooled cross-sectional data from 2 ethnically diverse cohorts of community-living adults: the Boston Puerto Rican Health Study (n = 939) and the Nutrition, Aging, and Memory in Elders study (n = 1017). Individuals in both cohorts underwent anthropometric and laboratory measurements and dietary and health assessments using validated questionnaires between the years 2003 and 2007. Cognitive outcomes included measures of global cognition [Mini-Mental Status Exam (MMSE)], depression (Center for Epidemiological Studies Depression Scale), and 3 factor scores for the domains of attention, executive function, and memory that were derived from a detailed set of neuropsychological tests. Low plasma vitamin B-12 concentrations were associated with poorer MMSE scores and higher depression scores, and low vitamin B-6 concentrations were associated with lower MMSE and worse attention and executive function in the multivariate analysis. In contrast, MTHFR genotype, folate, and homocysteine were not associated with cognition or depression in either ethnicity-pooled or stratified analysis. The current study did not find evidence of an association between the MTHFR C677T TT genotype and impaired cognition or depression in a population with adequate folate status and a high prevalence of cognitive impairment and depression.

A review of lifestyle factors that contribute to important pathways associated with major depression: Diet, sleep and exercise

“…Other investigations on the relationship between nutrients and depression have demonstrated a role of folate (Farah, 2009, Gilbody et al, 2007, Morris et al, 2008, tryptophan (Cowen et al, 1989, DeMyer et al, 1981, Maes et al, 1987, zinc (Cope and Levenson, 2010, Szewczyk et al, 2011, iron (Maes et al, 1996, Stewart and Hirani, 2012, Vahdat Shariatpanaahi et al, 2007, Yi et al, 2011, CoQ10 (Maes et al, 2009b), vitamin B6 (Merete et al, 2008, Moorthy et al, 2012, Skarupski et al, 2010, Williams et al, 2005, vitamin B12 (Hintikka et al, 2003, Moorthy et al, 2012, and selenium (Gao et al, 2012, Mokhber et al, 2011, Pasco et al, 2012. However, findings on most of these nutrients require further investigation before definitive conclusions about their relationship with depression can be made.…”

Emerging roles for folate and related B-vitamins in brain health across the lifecycle

“…Indeed, a review by Smith (41) some years ago reported that 90 out of 100 published cross-sectional and prospective studies showed a link between elevated homocysteine and/or low B-vitamins concentrations with cognitive dysfunction. Most of these studies have focused on elevated plasma homocysteine concentrations (42)(43)(44)(45)(46) , and/or a combination of suboptimal status of folate and vitamin B 12 (47)(48)(49)(50)(51)(52)(53)(54) and to a much lesser extent on vitamin B 6 ( 55,56) . To the authors' knowledge, no published study thus far has focused on riboflavin alone as a potential contributor to cognitive health.…”

Impact of consumption of B-group vitamins on cognitive functions of women after menopause

“…zwracają uwagę na fakt, że niski poziom witaminy B 12 był skojarzony z gorszymi wynikami w teście MMSE (Mini Mental State Examination) oraz z więk-szym ryzykiem wystąpienia depresji u starszych osób. Przeciwnie natomiast w tych badaniach nie stwierdzono, aby foliany i homocysteina miały wpływ na funkcje poznawcze i poziom depresji [20].…”