[Studies of the relationship between the nutritional status of lactating mothers and milk composition as well as the milk intake and growth of their infants in Beijing. Pt. 5. Essential inorganic elements and vitamins in human milk].

The contents of vitamin A, vitamin B1, vitamin B2, niacin, and vitamin C in the breastmilk of 152 lactating mothers, as well as ash, calcium, phosphorus, magnesium, copper, zinc, and iron in 132 lactating mothers were measured within 6 months of lactation. The results indicated that the breastmilk vitamin B2 and zinc contents of urban mothers in Beijing were significantly higher than those of suburban and rural mothers. However, when lactation continued, the contents of these 2 elements in breastmilk decreased. The correlation analysis of these results showed that the animal protein intakes of the mothers were highly correlated with their breastmilk, vitamin B2, and zinc contents (r=0.75, p0.01 for vitamin B2; r=0.57, p. 0.05 for zinc). The average intakes of all nutrients from breastmilk alone, with the exception of vitamin B2 and vitamin C, could not meet the Chinese RDA for these infants. This was true especially for vitamin B1, niacin, zinc, and iron intakes which were substantially below the RDA. (author's modified)