Vitamin E in fortified cow milk uniquely enriches human plasma lipoproteins¹²³⁴

ABSTRACT

Background:

Milk fat may contribute to atherogenesis in humans.

Objective:

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

Design:

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 -α-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 -α-tocopheryl acetate) and synthetic ( all-rac -α-tocopheryl acetate) vitamin E in milk with delivery of all-rac -α-tocopheryl acetate in orange juice (200 mg/d in each group). In experiment 3 ( n = 7), we compared delivery of 30 mg all-rac -α-tocopheryl acetate/d in milks with and without added vitamins A and D.

Results:

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.

Conclusions:

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.