Considering optimal vitamin intakes

Abstract

I tried to calculate the saturation amounts of vitamins for humans based on the data concerning the urinary excretion of vitamins. The saturated amounts of vitamins B1, B2, B6, and C were 1.2 mg/1,000 kcal, 2.2 mg/1,000 kcal, 0.054 mg/g protein, and 210 mg/d, respectively. Those of nicotinamide, pantothenic acid, folic acid, and biotin were 28 mg/1,000 kcal, 28 mg/d, 0.77 mg/d, and 0.09 mg/d, respectively. The values of these vitamins were almost 3-fold higher than those of Dietary Reference Intakes of vitamins which are established by the Ministry of Welfare and Labor. In addition, I surveyed a functional biomarker of vitamins. The participants were divided into three groups using the upper (n=10), middle (n=9), and lower tertiles (n=10) based on the urinary excretion amounts of 2-oxo acids. The administration of capsules containing the daily necessary amounts of vitamins led to a decrease in the urinary excretion in participants belonging to the upper tertile. A similar phenomenon was observed in the middle tertile, but not in the lower tertile. Thus, urinary 2-oxo acids might be useful functional biomarkers for vitamin nutritional status.