Effectiveness of Vitamin D in Infancy in Relation to the Vitamin Source

This report concerns the preliminary findings regarding the utilization by the human infant of vitamin D from different sources. The criterion chosen was the quantity of calcium retained by well infants given the same amount of milk and the same rat unitage of vitamin D. Irradiated evaporated milk containing 50 units,∗ and evaporated milk containing the unsaponifiable fraction of cod liver oil (Zucker concentrate) allowing 150 units per quart of reconstituted milk respectively, were compared with evaporated milk plus vitamin D given separately as a cod liver oil containing 40 units of D per gram. The Zucker concentrate milk was mixed with plain evaporated milk, and the quantities of cod liver oil were so chosen that the vitamin D unitage of each diet was constant for any given intake of milk, and was regulated by the amount present in the irradiated milk. The youngest infants received only 22 units daily, but by 16 weeks of age, all the infants were ingesting approximately 50 units of D daily. The plan of study was to give each of the 3 experimental diets to a group of infants of the same age and milk intake; after a period of about 6 weeks, the diets were changed so that each infant received each diet in turn. At the beginning of the study, 3 infants were from 5 to 8 weeks of age; 3 from 16 to 24 weeks; and one infant a year old was given each diet in turn. The relations observed between calcium intake and retention per kilogram body weight are shown in the chart. The source of vitamin D used in each experiment is indicated by the different symbols. The line shows the average curve of retention :intake obtained from over 200 experiments upon infants having the same age range and milk intakes, but given approximately 125 units of vitamin D daily in the form of cod liver oil.