Vitamin B-6 requirements of elderly men and women.
The vitamin B-6 requirements of 12 men and women over 60 y old were studied. The protocol consisted of a 5-d baseline period and four experimental periods during which the subjects successively received 0.003, 0.015, 0.0225 and 0.03375 mg of vitamin B-6/(kg body wt.d). Dietary protein was 1.2 or 0.8 g/(kg body wt.d). At 5- or 6-d intervals, xanthurenic acid (XA) after a 5-g L-tryptophan load and 4-pyridoxic acid (4-PA) in 24-h urine, erythrocyte aspartate aminotransferase activity coefficient (EAST-AC) and plasma pyridoxal-5'-phosphate (PLP) were measured. These measurements were abnormal during vitamin B-6 depletion but returned to normal during repletion. Men who ingested approximately 120 g protein/d required 1.96 +/- 0.11 mg of vitamin B-6 to normalize XA; women who ingested 78 g protein/d required 1.90 +/- 0.18 mg of vitamin B-6 to normalize XA. To attain normal levels of EAST-AC and 4-PA in men, 2.88 +/- 0.17 mg of vitamin B-6 were needed; to normalize PLP, 1.96 +/- 0.11 mg of vitamin B-6 were required. Women required 1.90 +/- 0.18 mg or more of vitamin B-6 to normalize these measurements. Vitamin B-6 requirements were not decreased in two of three subjects who ingested 54 g of protein daily. Thus, vitamin B-6 requirements of elderly men and women are about 1.96 and 1.90 mg/d, respectively.
Ribaya-Mercado
J D
JD
U.S. Department of Agriculture, Human Nutrition Research Center on Aging, Tufts University, Boston, MA 02111.
Russell
R M
RM
Sahyoun
N
N
Morrow
F D
FD
Gershoff
S N
SN
D000368:Aged; D001219:Aspartate Aminotransferases / Q000097:blood; D004032:Diet; D004044:Dietary Proteins / Q000008:administration & dosage*; D005260:Female; D005526:Food, Formulated; D006801:Humans; D008297:Male; D008875:Middle Aged; D009751:Nutritional Requirements; D011732:Pyridoxal Phosphate / Q000097:blood; D011735:Pyridoxic Acid / Q000652:urine; D011736:Pyridoxine / Q000008:administration & dosage*; D026681:Vitamin B 6 Deficiency / Q000378:metabolism*; D014977:Xanthurenates / Q000652:urine
D004044:Dietary Proteins; D014977:Xanthurenates; C028330:xanthurenic acid; D011735:Pyridoxic Acid; D011732:Pyridoxal Phosphate; D001219:Aspartate Aminotransferases; D011736:Pyridoxine