Serum concentrations of alpha-tocopherol after ingestion of various vitamin E preparations.
The rat-fetal-resorption test currently is used to assess the biological activity of vitamin E compounds. Previous studies in humans, however, suggest that rat assays underestimate the potency of free tocopherol relative to the acetate ester form and of RRR-alpha-tocopheryl acetate relative to all-rac-alpha-tocopheryl acetate. Therefore, we studied the serum concentrations of alpha-tocopherol after ingestion of RRR-alpha-tocopheryl acetate, all-rac-alpha-tocopheryl acetate, RRR-alpha-tocopherol, RRR-alpha-tocopheryl succinate, and RRR-alpha-tocopheryl acetate plus apple pectin by each of 20 adult human subjects. Measurements were made at 0, 8, 24, and 48 h after ingestion of 800 IU of the various preparations. The results at 24 h were representative of the differences observed. The mean increase in concentration of alpha-tocopherols (mg/g lipid) in 24 h was 71.2% after RRR-alpha-tocopherol, 63.3% after RRR-alpha-tocopherol acetate, and 41.2% after RRR-alpha-tocopherol succinate. Animal assay data do not correlate with data from studies of absorption and retention in serum of alpha-tocopherols ingested by humans.
D000328:Adult; D005260:Female; D006801:Humans; D007408:Intestinal Absorption; D008055:Lipids / Q000097:blood; D008297:Male; D008875:Middle Aged; D013237:Stereoisomerism; D024505:Tocopherols; D014810:Vitamin E / Q000031:analogs & derivatives / Q000097:blood* / Q000378:metabolism; D024502:alpha-Tocopherol / Q000031:analogs & derivatives*
D008055:Lipids; D014810:Vitamin E; D024502:alpha-Tocopherol; D024505:Tocopherols