Changes in human milk at 0600, 1000, 1400, 1800, and 2200 h.

Milk from six mothers was collected every 4 h from 0600 to 2200 h. Total lipid and cholesterol, lactose, glucose, protein N, indicator acids 12:0, 14:0, and 18:2, and alpha- and gamma-tocopherols were analyzed. Total calories were calculated. Although considerable variation was seen in the lipid content, this was not significant and was apparently due to individuality. Differences in the other lipid components were not significant and were generally related to the total lipid content. Except for protein N (p less than 0.05), none of the other components varied significantly. Based upon these data and the results of others, the time of sampling of human milk should be matched to the population being studied to obtain consistent results, at least with lipids.