Micronutrient status, with special reference to vitamin B6.Eur J Clin Nutr. 1997 Nov; 51 Suppl 3:S32-8.EJ
To assess the adequacy of micronutrient status among the adult population, with special reference to vitamin B6 status.
DESIGN AND SUBJECTS
Micronutrient status was assessed among a random sample of the adult Dutch population (reference group, n = 300), aged 20-79 y, stratified for age and gender, and among a group with a low vitamin B6 intake (n = 144).
Low vitamin B6 groups had lower mean levels of erythrocyte and plasma pyridoxal (PL) and pyridoxal-5'-phosphate (PLP), urinary excretion of 4-pyridoxic acid, basal and stimulated erythrocyte aspartate aminotransferase (EAST) and erythrocyte alanine aminotransferase (EALT) activities and EAST stimulation coefficients but not of EALT stimulation coefficients, handgripstrength and 24 h homocysteine excretion before and after a methionin load test. Besides, plasma levels of vitamin C, B12 and folate were lower among low B6 than among reference groups indicating a combined low vitamin status. Direct biomarkers of vitamin B6 intake (plasma PLP and 4-pyridoxic acid excretion) were significantly related to more functional parameters (EAST, EALT and alpha-EAST). Among random reference groups the prevalence of plasma PLP values below 19 nmol/l was 3-7% for different age-gender groups, with the highest value of 16% among men aged 50-79 years. The prevalence of high values of erythrocyte glutathion reductase stimulation coefficient (alpha-EGR) and low levels of serum vitamin B12 and C was not more than 5% among different age-gender reference groups.
Direct biomarkers of vitamin B6 intake confirmed the preselection of a group with a low vitamin B6 intake. The results suggest that the sensitivity of vitamin B6 status parameters for low vitamin B6 intake was highest for the direct vitamin B6 status parameters and lowest for handgripstrength and homocysteine excretion after a methionin load; results for enzyme stimulation coefficients were intermediate. The prevalence of below adequate status parameters for vitamin B2, B6, B12 and C was not more than 7% among the different age-gender groups, with the exception of a value of 16% for plasma PLP levels below 19 nmol/l among men aged 50-79.