Dietary Intake of Nutrients with Adequate Intake Values in the Dietary Reference Intakes for Japanese

In 2004, the Dietary Reference Intakes for Japanese (DRIs-J) were established to replace the Recommended Dietary Allowances (RDAs) for Japanese as the official nutritional standards in Japan (1). In the DRIs-J, there are three useful categories for the prevention of nutrient deficiency. The Estimated Average Requirement (EAR) is the intake that would meet the needs of 50% of a population of a specific sex and age, and was established to allow evaluation of insufficient nutrient intake. The RDA is calculated based on the EAR, and is defined as the intake that satisfies the requirements of nearly all individuals in a sexand age-specific population. When there is insufficient evidence to establish both the EAR and the RDA, the Adequate Intake (AI) is established as a surrogate value. These DRI categories were established with reference to the concept of DRIs in the United States and Canada (2). AI in the United States and Canada is defined as “the recommended average daily intake level based on observed or experimentally determined approximations or estimates of nutrient intake by a group (or groups) of apparently healthy people that are assumed to be adequate; used when an RDA cannot be determined” (2). In the United States and Canada, the AIs for various nutrients are determined using several different methods, including experimental derivation, mean intake, and median intake (2). Similarly, in the DRIs-J, AI is defined as “a sufficient intake level to maintain the health of and prevent the nutrient deficiency of almost all members of a population” (3). Although several methods were used to establish the AIs in the current version of the DRIs-J 2010, the majority (except those for infants) were determined based on the median intakes of healthy people (3). In the DRIsJ 2010, AIs were established for individuals aged 1 y for 10 nutrients: n-6 and n-3 polyunsaturated fatty acids (PUFAs), vitamin D, vitamin E, vitamin K, pantothenic acid, biotin, potassium, phosphorus, and manganese. The AIs for seven of these nutrients were determined based on the median intakes reported by the National Health and Nutrition Survey-Japan (NHNS-J). The AIs for biotin and manganese were determined based on the mean intakes of a small Japanese population, because intake data for these nutrients were not assessed in the NHNS-J. The AI for vitamin K was determined by an Report Dietary Intake of Nutrients with Adequate Intake Values in the Dietary Reference Intakes for Japanese