Changes in vitamin B-6 status indicators of women fed a constant protein diet with varying levels of vitamin B-6.
Changes in vitamin B-6 status indicators were evaluated in vitamin B-6-replete subjects. Ten young women consumed diets providing 85 g protein/d and 1.03, 1.33, 1.73, and 2.39 mg vitamin B-6/d for 12 or 15 d during four successive diet periods; in a second study, six women were fed diets providing 85 g protein/d and 0.84, 1.14, and 2.34 mg vitamin B-6/d for 10 or 12 d during three successive diet periods. Vitamin B-6 status indicators showing significant differences among intakes included urinary excretion of 4-pyridoxic acid and total vitamin B-6, pyridoxal 5'-phosphate and total vitamin B-6 in plasma, and xanthurenic acid excretion after a 2-g L-tryptophan load. Significant correlations were found between vitamin B-6 intake and 4-pyridoxic acid, total vitamin B-6, plasma pyridoxal 5'-phosphate, plasma total vitamin B-6, erythrocyte alanine aminotransferase percentage stimulation and postload excretion of xanthurenic acid and volatile amines (kynurenine plus acetylkynurenine). Depending on the indicator, between 20% and 70% of the subjects had inadequate values for 4-pyridoxic acid, total vitamin B-6, plasma pyridoxal 5'-phosphate, and erythrocyte alanine aminotransferase percentage stimulation at a vitamin B-6 intake of 1.33 mg/d (0.016 mg vitamin B-6/g protein). A ratio of dietary vitamin B-6 to protein > 0.016 mg/g is required for adequate vitamin B-6 status in women.
Hansen
C M
CM
Department of Nutrition and Food Management, Oregon State University, Corvallis 97331-5103, USA.
Leklem
J E
JE
Miller
L T
LT
D000328:Adult; D004044:Dietary Proteins / Q000008:administration & dosage*; D005260:Female; D006801:Humans; D009752:Nutritional Status; D011735:Pyridoxic Acid / Q000652:urine; D011736:Pyridoxine / Q000008:administration & dosage* / Q000097:blood / Q000378:metabolism*; D000637:Transaminases / Q000097:blood
D004044:Dietary Proteins; D011735:Pyridoxic Acid; D000637:Transaminases; D011736:Pyridoxine