The stability of vitamins A and E in edible oils

Vegetable oils are in themselves a major source of vitamin E and are also used for fortification with vitamin A. Approximately 90% of Americans are facing insufficient dietary intake of vitamin E. Hypovitaminosis A is a major public health problem in many developing countries. Both vitamin deficiencies can be overcome by an adequate intake of fortified plant oils. Many fortification programs have been initiated to reduce the prevalence of vitamin A deficiency in developing countries. Studies evaluating the stability of vitamins in fortified oil were performed to improve the efficiency in supplying vitamins A and E to people. The stability of vitamins was shown to depend on storage conditions, such as duration of storage, material of container, oxygen tension, temperature, oxidative status of the plant oil and, most importantly, exposure to light. Storage of fortified soybean oil in polyethylene terephthalate bottles under household-representative conditions for 56 days was shown to induce a substantial loss of vitamins A and E. The oxidative degradation of vitamins A and E leads to the formation of not yet fully known decomposition products whose biological effects still need to be investigated. The low stability of vitamins A and E and the formation of yet unknown oxidized vitamin products require a re-evaluation of the amounts of vitamins added to the edible oils and an optimization of the storage conditions for these products to ensure adequate intake of vitamins A and E.