Predictors of vitamin B6 and folate concentrations in older persons: the InCHIANTI study

BACKGROUND: Low dietary intake and low serum concentrations of vitamin B6 and/or folate are associated with increased risk of vascular events, possibly because of their association with inflammation, which plays a crucial role in the pathogenesis of cardiovascular diseases. METHODS: Using data from 1320 participants in the population-based InCHIANTI study (586 men and 734 women; median age, 69 years; range, 21-102 years) for whom complete data on folate, vitamin B6, inflammatory markers, 5,10-methylenetetrahydrofolate reductase (MTHFR) C677T sequence variant, and important covariates were available, we evaluated the association of inflammatory markers with circulating concentrations of vitamin B6 and folate, independently of dietary vitamin intake, circulating vitamin concentrations, and MTHFR C677T sequence variant. RESULTS: According to multiple linear regression analysis, C-reactive protein and interleukin-6 receptor were strongly and negatively associated with circulating vitamin B6 but not with folate concentrations, independent of age, sex, serum creatinine, serum albumin, total energy intake, smoking history, dietary nutrient intake, and circulating homocysteine and vitamin concentrations. Serum folate concentrations were related to MTHFR 677 TT genotype in persons with folate intake in the lowest tertile (< 221.2 microg/day). Vitamin C and retinol intakes were strongly and positively associated with serum folate concentrations independent of age, sex, serum creatinine, serum albumin, total energy intake, smoking history, homocysteine plasma concentrations, dietary nutrient intakes, serum vitamin B6 and vitamin B12 concentrations, and MTHFR C677T sequence variant. CONCLUSIONS: Low serum vitamin B6, but not serum folate, concentrations are independent correlates of the proinflammatory state, and both are influenced by antioxidant reserves.     

Abnormal brain response of chronic schizophrenia patients despite normal performance during a visual vigilance task

Deficits of attention are common among individuals with schizophrenia (SZ) and are related both to genetic liability to the disorder and to functional outcome among patients. To explore the brain systems underlying these attentional abnormalities, we compared the response of nine patients with chronic SZ or schizoaffective disorder to that of 10 matched healthy individuals performing a simple visual vigilance task during functional magnetic resonance imaging. The two groups performed equivalently on the task. When the blood oxygen level dependent (BOLD) signal during identification of a target letter among similar-looking letters was compared to the response during fixation trials, both groups showed multiple clusters of significant brain response in widespread cortical regions. Compared with healthy participants, SZ patients showed a diminished response in the inferior frontal cortex and an abnormally enhanced response in right postcentral gyrus, right medial temporal lobe and left cerebellum. The results suggest that abnormalities of functional brain response to attentional tasks can be observed among patients with SZ even when behavioral performance is unimpaired, and provide further evidence that brain systems related to attention are likely to be involved in the pathophysiology of the disorder.