Near-infrared interactance in assessing superficial body fat in exclusively breast-fed, full-term neonates.

Near-infrared interactance was used to study changes in the percentage of superficial body fat in 91 healthy, breast-fed, full-term neonates during the first five days of life (group 1) and subsequently at two and four weeks of age in 28 infants (group 2). Near-infrared interactance was recorded as optical densities (ODs) at 937 nm and 947 nm. OD ratio agreed acceptably with fat content determined chemically in 16 pork meat samples. No correlation between OD ratio and skinfold thickness (measured at the same site in the subscapular area) was found. In group 1, no change was found in OD ratio, and maximum weight loss (at two days of age) was only 3%. In group 2, percentage of superficial body fat (estimated via OD ratios) increased by only 2%, despite normal weight gain (26% increase from birth weight). Breast feeding thus maintains adequate weight gain without accelerating superficial fat accumulation during the neonatal period.