Effect of Giving Phosphate Supplements to Breast-Fed Babies on Absorption and Excretion of Calcium, Strontium, Magnesium, and Phosphorus

The intake of milk and the retention of its constituents while the newborn rabbit doubles its weight

“…'The percentage of fat in the body is commonly higher at the end of the suckling period than it is at the ti me of birth, in rabbits as well as in other mammals (Spray & Widdowson, 1950), bul: the rise evidently does not begin until after the 3rd day, and it seems likely that young rabbits pass through a period of partial undernutrition during the first 3 days after birth. A similar period of undernutrition was described in guinea-pigs by Widdowson & McCance (1955) and was considered to be physiological.…”

Balance of Net Base in the Rat

“…This is in agreement with tire observation by Slater (12) of a two-to fivefold increase in rates of retention of calcium, magnesium, phosphorus, and NB in 1-week-old babies fed cow's milk. Also, Slater (12) and Widdowson et al (15) gave oral supplements of sodium and potassium phosphate to breast-fed infants. In both studies, elevated rates of retention of calcium, magnesium, and phosphorus resulted.…”

Significance of hypocalcaemia in neonatal convulsions.

“…A dietary mechanism for hypocalcaemia developing at this age is widely accepted (Gittleman and Pincus, 1951;Oppe and Redstone, 1968;Dundon and O'Brien, 1967), the infant is faced with a high phosphate load as a result of early cow's milk feeding, and hyperphosphataemia results, probably as a result of the low glomerular filtration rate of the immature kidney. Confirmation of the inability of the newborn to excrete a phosphate load is provided by Widdowson et al (1963) who added 120 mg. extra phosphorus daily to the diet of 11 baby boys aged between 6 and 8 days; they showed that phosphate retention followed. The hypocalcaemia which follows may be accounted for in a number of ways: either the newborn may fail to produce parathormone in response to the stimulus of hyperphosphataemia, or the parathyroid may be unable to produce the increased amounts required to maintain normal calcium levels in face of the avidity of rapidly growing bone.…”