Vitamin B6 status of breast-fed infants in relation to pyridoxine HCl supplementation of mothers.

The vitamin B6 nutritue of breast-fed infants was evaluated by vitamin B6 intake, plasma pyridoxal 5'-phosphate (PLP) concentration, and growth patterns during the infants' first 6 mo of age. Vitamin B6 intakes of 47 healthy, term infants were significantly correlated with four levels of maternal vitamin B6 supplements: 2.5, 4.0, 7.5, or 10.0 mg pyridoxine (PN) HCl/d and met the B6 Adequate Intake (AI, 1998) of 0.1 mg/d for infants 0 to 6 mo. Only infants whose mothers received 10.0 mg PN x HCl/d exceeded or met the Recommended Dietary Allowances (RDA, 1989) of 0.3 mg vitamin B6/d from 4 to 6 mo of age. Plasma PLP concentrations of infants, measured at 1, 4, and 6 mo of age paralleled their mother's vitamin B6 intake. Most infants showed normal growth. The findings indicated that a maternal PN x HCl supplement of 2.5 mg/d provided an adequate amount of vitamin B6 in breast milk (0.15 mg/d) for the vitamin B6 status parameters and the growth of breast-fed infants.

Dependability and precision of anthropometric measures in a longitudinal field study in an Egyptian village.

Reliability and its components, precision and dependability, are analyzed for a complex dataset involving longitudinal anthropometric measurements on subjects of varying ages in an Egyptian village setting. Results are compared with other published datasets. Technical error of measurement is similar to or compares favorably with other datasets for both adults and children. Overall reliability is strongly influenced by dependability coefficients, which are calculated in this analysis over relatively longer time periods (2 weeks for young children and longer for older individuals) than in other comparable datasets. It is evident that some components of the theoretical construct of imprecision, i.e., measurement error derived from variation over longer periods of time in factors contributing to accuracy, are actually captured in the analytical component of variance called undependability.