BOSTON—Low vitamin B6 concentrations were associated with inflammation, higher oxidative stress and metabolic conditions in a new study from Tufts University (Am J Clin Nutr. 2010 Feb;91(2):337-42). Researchers found vitamin B6 may influence cardiovascular disease (CVD) risk in older Puerto Rican adults through mechanisms other than homocysteine.
They measured the following markers of inflammation and oxidative stress: C-reactive protein (CRP), and an oxidative DNA damage marker, urinary 8-hydroxydeoxyguanosine (8-OHdG), in Puerto Rican adults who were living in Massachusetts (n = 1,205, aged 45 to 75 years). Plasma pyridoxal-5'-phosphate (PLP), the active form of vitamin B6, was also measured.
They observed a strong dose-response relation of plasma PLP concentration with plasma CRP. Increasing quartiles of PLP were significantly associated with lower CRP concentrations (geometric means: 4.7, 3.6, 3.1, and 2.5 mg/L; P< 0.0001) and with lower urinary 8-OHdG concentrations (geometric means: 124, 124, 117, and 108 ng/mg creatinine; P=0.025) after multivariate adjustment. These negative associations persisted after plasma homocysteine was controlled for. Plasma PLP concentrations were significantly correlated with plasma fasting glucose (r = –0.1, P = 0.0006), glycated hemoglobin (r = –0.08, P = 0.006), and homeostasis model assessment of β cell function (r = 0.082, P = 0.005). Metabolic syndrome, obesity and diabetes were also significantly associated with low plasma PLP concentrations (P = 0.011, 0.0007, and 0.004, respectively).
Other studies have found low vitamin B-6 status is linked to an increased risk of CVD and the Tuffs’ researchers wanted determined cardioprotective effects of vitamin B-6 independent of homocysteine, which suggest additional mechanisms may be involved.