Researchers from Oregon State University in the US found that bioavailability of vitamin E from a fortified breakfast cereal was significantly greater than from a supplement. The poor absorption rate from the supplement could explain the conflicting results from vitamin E intervention studies, they add.
Vitamin E bioavailability was evaluated in three four-day trials, each four weeks apart. Five fasting subjects first consumed 400 IU d9-alpha-tocopheryl acetate in a capsule along with low-fat milk, followed by 41g of ready-to-eat wheat cereal containing 30 IU d9-alpha-tocopheryl acetate, and finally 45g cereal containing 400 IU d9-alpha-tocopheryl acetate. Five months later, they each took a 400-IU capsule with 41g vitamin E-free cereal. Blood was obtained up to 72 hours after the start of each trial.
Writing in this month's American Journal of Clinical Nutrition (vol 79, no 1, 86-92), the researchers report that bioavailability of vitamin E from the 400 IU fortified breakfast cereal was 26 times greater than that from the 400 IU supplement. The 30 IU cereal also had a vitamin E bioavailability fives times that of the 400 IU capsule.
The authors concluded:"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."
A recent study found that eating foods which contain significant amounts of vitamin E may protect against the development of type 2 diabetes. But taking the vitamin in supplement form seemed to offer no further protection. The vitamin has also been implicated in reduced stroke risk and protection against cardiovascular disease but this has been hotly contested by recent findings.