Secretion of Vitamin D in Milks of Women Fed Fish Liver Oil

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Abstract
The vitamin D level in the milks of eighteen mothers who received no preformed sources of the factor in the dietary during pregnancy was inappreciable, ranging from traces to less than 10 I.U. per quart. Three cases showed values of 17, 28 and 40 I.U. per quart. The average vitamin D content per quart of milk of mother supplied during the latter half of pregnancy was as follows: 10 I.U. for seven mothers given from 32,000 to 96,000 I.U. of supplement. 53 I. U. for nine mothers given from 128,000 to 224,000 I.U. of supplement. 62 I.U. for five mothers given from 256,000 to 320,000 I.U. of supplement. 53 I.U. for six mothers given from 416,000 to 480,000 I.U. of supplement. Two mothers given a single dose of 32,000 I.U. during labor secreted milks from 3 to 8 days later, which bioassayed 91 and 216 I.U. per quart (0.3 and 0.7%, respectively, of calculated recovery). Seven women supplied 40,000 I.U. of vitamin D daily from labor to about 10 days later yielded milks, the vitamin D content of which averaged 310 I.U. per quart (range 125 to 583 I.U.). It is concluded, therefore, that for the purpose of fortifying human milk with vitamin D for infant use, supplementation of the mother with fish liver oil during pregnancy is not a practical method. Other beneficial effects on mother and fetus are not overlooked, however. Vitamin D must be taken just prior to or during lactation in order to enrich the milk with the factor appreciably. The minimal dose of vitamin D which, when added as a supplement to the mother's basal diet, will yield a satisfactory increase of vitamin D in her milk has not been determined. In an 8-day balance study a patient who received 40,000 I.U. daily in the latter group secreted about 1.3% of the ingested vitamin D in the milk and 6.9% in the stools. Approximately 36% of the factor was accounted for in blood samples taken about 14 hours after the dose. It is presumed that the vitamin D of fish liver oil was very efficiently absorbed, the larger proportion, however, having been inactivated or destroyed very rapidly.