Stability of thiamine and vitamins E and A during storage of enteral feeding formula

The content of thiamine (vitamin B-1), vitamin E (alpha-, gamma-, and delta -tocopherol) and vitamin A (all-trans-retinol and 13-cis-retinol) in five commercial enteral feeding formulas was studied. These formulas provide a l arge amount of vitamins: 2.5-3, 3.1, and 1.6-fold above the U.S. daily reco mmendations (U.S. RDA) for thiamine, vitamin E, and vitamin A, respectively . The stability of thiamine and vitamins E and A of two of the enteral feed ing formulas was followed throughout 9 months of storage in the dark at 4 d egrees, 20 degrees, and 30 degreesC. According to our results in all of the storage conditions studied, the enteral formula covered the U.S. RDA level s for thiamine and vitamin E, but in the case of vitamin A the U.S. RDA req uirements are met only when the enteral sample has been kept in storage les s than 3 months. After 6 months of storage, the decrease in vitamin A was s o drastic that the level of vitamin covered only 0.9-0.3-fold of the U.S. R DA and after 9 months it covered only 0.2-0.0-fold of U.S. RDA. The manufac turer shelf life of the formula studied was 1 year; and, because enteral fe eding solutions are often placed in storage conditions of uncontrolled temp erature and humidity, these results should be taken into consideration with regard to the shelf life.