The total content of vitamin D in human milk and cow's milk.

1. It was shown that the water-soluble fraction of cow's milk and human milk did not possess significant antirachitic activity on rats. Whole cow's milk was found to contain 3.8 i.u. vitamin D/l. Whole human milk contained 15 i.u. vitamin D/l, of which 12 i.u. derived from the lipid fraction. 3. Thus the values found were much lower than the 204 i.u./l in cow's milk and 950 i.u./l in human milk given in the literature based on chemical determination of the sterol sulphate content.