Linus Pauling Institute

BACKGROUND: Conflicting results from vitamin E intervention studies suggest supplemental vitamin E malabsorption.

OBJECTIVE: We compared vitamin E bioavailability from a supplement with that from a fortified breakfast cereal.

DESIGN: Vitamin E bioavailability was evaluated by using deuterium-labeled all-rac-alpha-tocopherol in three 4-d trials (2 wk apart). Five fasting subjects sequentially consumed the following (with 236 mL fat-free milk): 400 IU d(9)-alpha-tocopheryl acetate (400-IU capsule), 41 g ready-to-eat wheat cereal containing 30 IU d(9)-alpha-tocopheryl acetate (30-IU cereal), and 45 g cereal containing 400 IU d(9)-alpha-tocopheryl acetate (400-IU cereal). Five months later (trial 4), they consumed a 400-IU capsule with 41 g vitamin E-free cereal. Blood was obtained up to 72 h after the start of each trial.

RESULTS: The mean (+/-SD) vitamin E bioavailabilities of the 30-IU cereal and the 400-IU cereal were 6 +/- 2 and 26 +/- 8 times, respectively, the vitamin E bioavailability of the 400-IU capsule. The areas under the 0-72-h d(9)-alpha-tocopherol curves for the 400-IU capsule, the 30-IU cereal, and the 400-IU cereal were 30 +/- 7, 153 +/- 43, and 765 +/- 164 micro mol. h/L (all trial comparisons, P < 0.0001). In trial 4, 3 subjects barely responded and 2 subjects had areas under the curve that were similar to their 400-IU cereal responses.

CONCLUSION: The low bioavailability of vitamin E from the 400-IU capsule and the variability observed when the capsule was consumed with cereal suggest that encapsulated vitamin E is poorly absorbed when consumed with a low-fat meal and that bioavailability can be enhanced by food fortification with vitamin E.