Vitamin E in fortified cow milk uniquely enriches human plasma lipoproteins

Milk fat may contribute to atherogenesis in humans.

We sought to offset the atherogenic potential of milk fat by adding polyunsaturated fat and vitamin E to milk.

We measured plasma lipids, lipoproteins, and tocopherol and LDL oxidation in normolipemic adults. In experiment 1 (n = 48), we compared delivery of 100 mg all-rac-alpha-tocopheryl acetate/d in capsules, skim milk, and 1%-fat milks containing soybean oil, milk fat, or both (1:1). In experiment 2 (n = 24), we compared delivery of natural (RRR-alpha-tocopheryl acetate) and synthetic (all-rac-alpha-tocopheryl acetate) vitamin E in milk with delivery of all-rac-alpha-tocopheryl acetate in orange juice (200 mg/d in each group). In experiment 3 (n = 7), we compared delivery of 30 mg all-rac-alpha-tocopheryl acetate/d in milks with and without added vitamins A and D.

Enrichment of milk fat with soybean oil did not alter plasma lipoproteins. Microdispersion of vitamin E in milks increased the molar ratio of plasma tocopherol to cholesterol by >2-fold compared with the molar ratio after consuming vitamin E capsules, whereas the molar ratios were comparable after ingestion of orange juice and capsules. Synthetic and natural vitamin E performed comparably. The enhanced plasma vitamin E:cholesterol attributed to milk increased protection of LDL against oxidation. Vitamins A and D did not affect vitamin E delivery by milk.

Milk augments vitamin E transport by human lipoproteins at intakes of 100-200 but not 30 mg/d. This augmentation is independent of the presence and type of fat in milk, its vitamin A and D contents, and whether the vitamin E is natural or synthetic.