Assessment of vitamin B6 status. Studies on pregnant women and oral contraceptive users

Abstract

The vitamin B6 status of 10 pregnant women (third trimester), 9 oral contraceptive agent users, and 12 notnpregnant women (controls) was investigated over a 10-week period by means of the erythrocyte glutamate-oxaloacetate transaminase (E-GOT) activation test and by measurements of whole blood pyridoxal phosphate levels. Blood pyridoxal phosphate levels in oral contraceptive agent users (7.6 plus or minus 1.1 ng/ml) were significantly lower than in the control group (9.6 plus or minus 1.7 mg/ml)indicating a relative vitamin B6 deficiency. Pyridoxal phosphate levels in pregnant women(5.1 plus or minus 1.3ng/ml) were even lower; in fact, no overlap was found in individual mean values between the pregnant and control groups. The E-GOT activation test did not indicate a vitamin deficiency in the pregnant women or in oral contraceptive agent users and the E-GOT activation factor did not correlate with blood pyridoxal phosphate levels unless results obtained after pyridoxine hydrochloride (20 mg/day) administration were included. The E-GOT activation test appears to be a poor indicator of vitamin B6 status, except in pronounced deficiency as it is less responsive to vitamin depletion than blood pyridoxal phosphate levels, and suffers from relatively large variations in individual control values. This may be a result of factors unrelated to vitamin B6 as blood pyridoxal phosphate levels remained fairly constant in the individuals investigated.