VITAMINS

The biological role of vitamin E has been attributed to its direct antioxidant function by acting as a lipid radical chain breaking molecule. Recently, indirect antioxidant and non-antioxidant functions of vitamin E have been proposed. The former is the functions preventing from oxygen stress by acting not as a radical scavenger, and the latter is the functions regulating of gene and protein expressions independent of its antioxidant functions. Since α-tocopherol has the highest antioxidant activity, many stronger functions observed in tocols and tocotrienols than in α-tocopherol are attributed to non-antioxidant mechanism. Furthermore, new recent findings concerning the vitamin E-specific binding proteins gave a clue to know the transport and supply of vitamin E to tissues and its tissue-specific roles depending on its distribution to specific tissues such as the central nervous system and the feto-maternal unit. In this paper I review the functions of vitamin E from the view-points as above mentioned.

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To clarify the different nutritional states of biotin between infants fed maternal milk or infant formulas, this study was undertaken to determine the biotin concentrations in serum and urine. There was no difference in serum biotin concentration among these infants. However, in early infants fed maternal milk, the urinary biotin concentration was 14.1 μg/g creatinine in average, compared to 70.2μg/g creatinine in infants fed maternal milk. This may be partly due to the lower concentration of biotin in colostrum, compared with mature milk. On the other hand, the urinary biotin concentrations were low in infants fed either standard formulas (for nursing of normal infants) or special formulas which were specially prepared for medical treatment and prevention of disease as well. These findings suggest that the biotin intake of these infants fed formulas, especially special formulas, may be not enough. The infant formulas should be appropriately improved to maintain normal growth and good health.

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The vegetables that the consumers purchase from stores and take in every day are diverse depending on the origin and growing conditions. However, we have only a single set of numerical values designated in the standard tables of food composition in Japan when we calculate nutrient of meal or food ingredients. The standard food compositions are to be the average of the nutrient of food that is marketed throughout the year, although some vegetables often contain high nutrients in the peak season while they have low values in the off-season. The climate of Japan might affect the difference of the values because the islands of Japan lie long north and south. In this study, we investigated 6 samples of vegetables (cabbage, Japanese radish, tomato, leek, spinach, sweet potato) that were sold in 6 supermarkets in Japan from 1999 to 2003, and analyzed the relation of the food compositions and the roots of products every other month. 1) The sales area and the producing area of the supermarket-sold vegetables tended to be close or same except in summer and winter season. 2) We found clear seasonal changes of the contents in the following samples; vitamin C of tomatoes was high in summer, vitamin C of leeks was low in summer, water of spinaches was high in summer, and carotene, vitamin C and sugar contents of spinaches were low in summer.

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