Triacylglycerol composition in colostrum, transitional and mature human milk
The vitamin E and fatty acid composition of human milk was determined in 40 milk samples (six colostral, 10 transitional, and 24 mature) obtained at different stages of lactation. Vitamin E was determined by high performance liquid chromatography with fluorescence detection of the various tocopherols. The total tocopherol level was significantly higher in early milk than in mature milk. The difference was due to a high content of alpha-tocopherol, as the content of beta- and gamma-tocopherol was similar in the three milk types. The total tocopherol content in mature milk correlated significantly with both the total lipid and the linoleic acid content. Significantly higher tocopherol/linoleic acid ratios were found in both colostrum and transitional milk than in mature milk. The colostral milk differed from the other milk types in fatty acid composition, as it had a lower content of lauric acid and a higher content of arachidonic acid and docosahexaenoic acid. The linoleic acid levels reported here are considerably higher than those reported previously in Sweden. Still, the ratio of alpha-tocopherol equivalent/linoleic acid exceeded 0.5 mg/g in all but three milk samples.