Dietary reference intakes for Japanese 2010: Water-soluble vitamins

Abstract

A potential approach for determining the estimated average requirement (EAR) is based on the observation that a water-soluble vitamin or its catabolite(s) can be detected in urine. In this approach, the urinary excretion of a water-soluble vitamin or its catabolite(s) increase when the intake exceeds the requirement. This approach is applied to vitamin B1, vitamin B2 and niacin. A second approach is to determine the blood concentration. In this case, the requirement is indicated by a value rather than a threshold level. The second approach is applied to vitamin B6, vitamin B12, foliate, and vitamin C. The recommended dietary allowance (RDA) was calculated by multiplying the EAR by 1.2. For pantothenic acid and biotin, there were insufficient data for determining the EAR. Thus, adequate intakes were set based on food surveillance data.