INFLUENCE OF VITAMIN B-6 INTAKE ON THE NUTRITURE AND GROWTH OF INFANTS FROM BIRTH TO SIX MONTHS OF AGE
Abstract
Vitamin B-6 is critical to normal development; however, data which quantitate vitamin B-6 requirements for human infants are limited. In rats, plasma pyridoxal phosphate (PLP) is reported to be a reliable indicator of vitamin B-6 nutriture. In this study PLP was examined in healthy, full-term infants in relation to their vitamin B-6 intakes and growth. Intakes of vitamin B-6 were estimated for formula-fed (FF) and for breast-fed (BF) infants whose mothers were supplemented with 2.5 or 15 mg pyridoxine(.)hydrochloride per day (PN(.)HCl). BF and FF infants were test weighed to assess vitamin B-6 intake at 1, 2, 4 and 6 months of age. Milk volume intake, assessed by test weighing, underestimated intakes measured directly by 7 to 14% during the six month period. Plasma PLP in cord at delivery was 219 (+OR-) 19 nM. At 1 to 5 days of age, BF infants had significantly lower plasma PLP levels, 73 (+OR-) 6 nM, compared to FF infants, 139 (+OR-) 16 nM. FF infants had the highest plasma PLP values and vitamin B-6 intakes, while BF infants of mothers receiving 2.5 mg PN(.)HCl/day the lowest values at each age. Irrespective of vitamin B-6 intake, mean PLP levels of all infants decreased from 1 to 6 months of age. This was especially evident in FF infants whose intakes varied only slightly (0.54 to 0.67 mg/day). Plasma PLP values were responsive to vitamin B-6 intakes ranging from 0.05 to 0.78 mg/day at 1 month but did not respond to intakes of 0.16 to 0.95 mg/day at 6 months of age. Infant growth was within acceptable ranges and no infant displayed overt deficiency symptoms of the vitamin. However, the findings from this study indicated that a maternal supplement of 15 mg PN(.)HCl/day during lactation was needed to insure that the BF infant's intake of vitamin B-6 meets the RDA (1980). Some BF infants of mothers supplemented with 2.5 mg PN(.)HCl/day may have less than optimal vitamin B-6 nutriture particularly in early infancy. These findings emphasize the need to re-evaluate the current RDA for lactating women and young infants.
Degree
Ph.D.
Subject Area
Nutrition
Off-Campus Purdue Users:
To access this dissertation, please log in to our
proxy server.