Institute of Medicine Releases New Dietary Reference Intakes for Calcium and Vitamin D
Calcium and vitamin D are essential nutrients for bone health. However, the optimum amounts that should be obtained through diet or supplements have not been definitively established. The Institute of Medicine (IOM) recently conducted a comprehensive literature review to provide dietary and supplementation recommendations. For both calcium and vitamin D, Recommended Dietary Allowances (RDAs) were established for all age groups except infants aged 0-12 months. RDAs are used when there is sufficient evidence to determine estimated average requirements; an RDA is expected to meet the requirement for 97% of the population. When there is insufficient evidence to determine RDAs, values are provided as Adequate Intakes (AIs), which are the amounts considered likely to maintain adequate status.
The new daily RDAs for vitamin D are 600 units for people aged 1-70 years, including pregnant and lactating women, and 800 units for adults > 70 years old. The AI for vitamin D for infants aged 0-12 months is 400 units. The new daily RDAs for calcium for adults are 1,000 mg if ≤ 70 years old, and 1,200 mg if > 70 years old. For children, the calcium RDA ranges from 700 mg/day for ages 1-3 years, up to 1,300 mg/day for ages 9-18 years. For infants, the AI is 200 mg/day for ages 0-6 months and 260 mg/day for ages 6-12 months. Tolerable upper intake levels (ULs) were also revised and vary by age but are generally 4,000 units/day for vitamin D and 2,000 mg/day for calcium.
The committee concluded that the majority of American and Canadian men under age 70 have adequate dietary intakes of calcium, but dietary calcium may be low for most women, especially adolescent girls. Data are less clear regarding the adequacy of vitamin D intake because of the difficulty in accounting for sun exposure. Data about health outcomes other than bone health were unreliable because studies often had mixed or inconclusive results. They also noted that the cut-off for determining vitamin D deficiency had not been scientifically established but that serum 25OHD levels ≥ 50 nmol/L (20 ng/mL) appear adequate for most people. They cautioned that using higher thresholds for starting treatment could result in unnecessary supplementation (Institute of Medicine Report Brief 2010 Nov 30). The full prepublication report can be found at National Academies Press.
For more information, see the Vitamin D intake and supplementation and Calcium intake and supplementation topics in DynaMed.
