PLASMA HOMOCYSTEINE CONCENTRATIONS CHANGE WITH VITAMIN-B-6 DEPLETION AND REPLETION IN YOUNG-WOMEN

Plasma total homocysteine concentrations were measured in 8 healthy pr emenopausal women who, after a 9-d adjustment period with a vitamin B- 6 intake of 1.60 mg/d, were marginally depleted of vitamin B-6 (0.45 m g/d) for 27 d, and then repleted with three levels of vitamin B-6 (1.2 6, 1.66 and 2.06 mg/d) for periods of 21, 21 and 14 days, respectively . Significant increases in plasma homocysteine concentrations were see n at the end of repletion periods 1 and 2, with a return to the adjust ment concentration by the end of repletion period 3. Plasma homocystei ne concentrations were negatively correlated with two measures of vita min B-6 status, urinary 4-pyridoxic acid and plasma pyridoxal phosphat e. Additional research is needed to determine whether plasma homocyste ine concentration may be used as a functional, or indirect, measure of vitamin B-6 status. (C) 1998 Elsevier Science Inc.