Vitamins A, E, and carotene: effects of supplementation on their plasma levels.
We conducted a randomized, double-blind trial among 59 generally well-nourished adults to determine the effects of vitamin A, vitamin E, and beta-carotene supplements on plasma retinol, alpha-tocopherol, and carotenoid levels. Over a period of 16 wk a daily alpha-tocopherol supplement of 800 IU approximately doubled plasma alpha-tocopherol levels (p less than 0.001), caused a small decrease in plasma carotenoids (p = 0.02), and produced a slight and statistically insignificant reduction in plasma retinol. A daily beta-carotene supplement of 30 mg (5000 retinol equivalents) approximately tripled plasma carotenoid levels (p less than 0.001) but did not affect plasma retinol or alpha-tocopherol. A daily retinyl palmitate supplement of 25,000 IU (13,750 retinol equivalents) did not appreciably affect plasma retinol, alpha-tocopherol, or carotenoid.
D000328:Adult; D002338:Carotenoids / Q000008:administration & dosage / Q000097:blood*; D004032:Diet; D004224:Diterpenes; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011897:Random Allocation; D000084562:Retinyl Esters; D014801:Vitamin A / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000097:blood*; D014810:Vitamin E / Q000008:administration & dosage / Q000097:blood*; D019207:beta Carotene
D004224:Diterpenes; D000084562:Retinyl Esters; D019207:beta Carotene; D014801:Vitamin A; D014810:Vitamin E; C014794:retinol palmitate; D002338:Carotenoids