Vitamin B-6 requirement and status assessment: young women fed a depletion diet followed by a plant- or animal-protein diet with graded amounts of vitamin B-6.
The vitamin B-6 requirement of young women consuming a high-protein diet (1.55 g/kg body wt) and the effect of protein quality on this requirement was studied. In addition, the response of clinical, functional, and biochemical measures of vitamin B-6 nutriture to short-term depletion and step-wise repletion of vitamin B-6 were evaluated. Eight healthy young women resided in a metabolic unit and were fed a formula depletion diet (< 0.05 mg vitamin B-6/d) for 11-28 d followed by either an animal-protein (AP) or plant-protein (PP) diet with successively increasing vitamin B-6 intakes (0.5, 1.0, 1.5, and 2.0 mg/d) for periods of 14-21 d. Animal proteins were primarily from dairy and poultry sources and plant proteins were primarily from legumes. Vitamin B-6 status measures were assessed at weekly intervals. Results showed that a PP diet does not elevate the vitamin B-6 requirement over that required for an AP diet given the high amount of dietary protein used in this study. It was also found that 0.015 mg vitamin B-6/g protein intake normalized most biochemical indexes of vitamin B-6 status (including those indicative of functional status), and that 0.020 mg/g protein normalized all biochemical measures except total urinary vitamin B-6. Adding a margin of safety to either the 0.015 or 0.020 mg/g protein intake would raise the vitamin B-6 requirement for young women above the currently recommended dietary allowance of 0.016 mg/g protein.
Kretsch
M J
MJ
USDA/ARS, WHNRC, Presidio of San Francisco, CA 94129, USA.
Sauberlich
H E
HE
Skala
J H
JH
Johnson
H L
HL
D000328:Adult; D000704:Analysis of Variance; D015415:Biomarkers; D003611:Dairy Products; D004044:Dietary Proteins / Q000032:analysis / Q000494:pharmacology* / Q000592:standards; D004305:Dose-Response Relationship, Drug; D005260:Female; D005526:Food, Formulated / Q000592:standards; D006801:Humans; D015596:Nutrition Assessment; D009751:Nutritional Requirements; D010940:Plant Proteins / Q000032:analysis / Q000494:pharmacology* / Q000592:standards; D011732:Pyridoxal Phosphate / Q000097:blood; D011735:Pyridoxic Acid / Q000652:urine; D011736:Pyridoxine / Q000008:administration & dosage / Q000032:analysis / Q000494:pharmacology*; D014977:Xanthurenates / Q000652:urine
D015415:Biomarkers; D004044:Dietary Proteins; D010940:Plant Proteins; D014977:Xanthurenates; C028330:xanthurenic acid; D011735:Pyridoxic Acid; D011732:Pyridoxal Phosphate; D011736:Pyridoxine