The Institute of Medicine Committee to Review Dietary Reference Intakes for Calcium
and Vitamin D comprehensively reviewed the evidence for both skeletal and nonskeletal
health outcomes and concluded that a causal role of calcium and vitamin D in skeletal
health provided the necessary basis for the 2011 Estimated Average Requirement (EAR)
and Recommended Dietary Allowance (RDA) for ages older than 1 year. For nonskeletal
outcomes, including cancer, cardiovascular disease, diabetes, infections, and autoimmune
disorders, randomized clinical trials were sparse, and evidence was inconsistent,
inconclusive as to causality, and insufficient for Dietary Reference Intake (DRI)
development. The EAR and RDA for calcium range from 500 to 1,100 and 700 to 1,300
mg daily, respectively, for ages 1 year and older. For vitamin D (assuming minimal
sun exposure), the EAR is 400 IU/day for ages older than 1 year and the RDA is 600
IU/day for ages 1 to 70 years and 800 IU/day for 71 years and older, corresponding
to serum 25-hydroxyvitamin D (25OHD) levels of 16 ng/mL (40 nmol/L) for EARs and 20
ng/mL (50 nmol/L) or more for RDAs. Prevalence of vitamin D inadequacy in North America
has been overestimated based on serum 25OHD levels corresponding to the EAR and RDA.
Higher serum 25OHD levels were not consistently associated with greater benefit, and
for some outcomes U-shaped associations with risks at both low and high levels were
observed. The Tolerable Upper Intake Level for calcium ranges from 1,000 to 3,000
mg daily, based on calcium excretion or kidney stone formation, and from 1,000 to
4,000 IU daily for vitamin D, based on hypercalcemia adjusted for uncertainty resulting
from emerging risk relationships. Urgently needed are evidence-based guidelines to
interpret serum 25OHD levels relative to vitamin D status and intervention.
Copyright © 2011 American Dietetic Association. Published by Elsevier Inc. All rights
reserved.