Values of water-soluble vitamins in blood and urine of Japanese young men and women consuming a semi-purified diet based on the Japanese Dietary Reference Intakes

We investigated the levels of water-soluble vitamins except for vitamin B6 in the blood and urine of Japanese college male (n=10) and female (n=10) students. They consumed for 7 d a semi-purified diet based on Japanese Dietary Reference Intakes to assess the Recommended Dietary Allowances (RDA) for water-soluble vitamins and to present some new normal values for blood and urine levels of water-soluble vitamins in Japanese. The blood and the 24-h urine samples were collected on the last day of the experiment and measured. The values of total vitamin B1 in whole blood, total vitamin B2 in whole blood, total cyanocobalamin in serum, total nicotinamide in whole blood, total pantothenic acid in whole blood, total folates in serum, total biotin in serum, and ascorbic acid in plasma were 104+-17 pmol/mL (mean+-SD), 216+-25 pmol/mL, 0.34+-0.05 pmol/mL, 59.1+-5.0 nmol/mL, 20.45+-0.37 nmol/mL, 15.6+-4.6 pmol/mL, 8.3+-0.5 pmol/mL, and 62+-10 nmol/mL, respectively, in males, and 90+-23, 234+-l8, 0.67+-0.20, 61.9+-6.0, 2.48+-0.30, 30.2+-8.6, 8.4+-0.3, and 67+-14, respectively, in females. There was a significant difference in the values of cyanocobalamin and total folates between men and women. The urinary excretion of vitamin B1, vitamin B2, cyanocobalamin, sum of the catabolic metabolites of nicotinamide, pantothenic acid, folates, biotin, and ascorbic acid were 665+-114 nmol/d, 562+-325 nmol/d, 93+-31 pmol/d, 84+-26 mumol/d, 9.3+-2.3 mumol/d, 19.4+-2.8 nmol/d, 83+-18 pmol/d, and 148+-51 mumol/d, respectively, in males, and 495+-212, 580+-146, 145+-49, 83+-19, 16.9+-l.3, 22.7+-2.7, 83+-23, and 140+-51, respectively, in females. There was a significant difference in the urinary excretion of cyanocobalamin, pantothenic acid and total folates between men and women. These values will be useful for the nutritional assessment of water-soluble vitamins for Japanese, although the examination period was short. In future, an experiment with various age groups and re-evaluation by repeated experiments will provide more accurate values.