Calcium
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Calcium builds and maintains bone and enables muscle and nerve function; adults need 1,000 mg/day (1,200 mg for women 50+ and men 70+).
Detail
Calcium is the body's most abundant mineral, concentrated in bones and teeth, which serve as a reservoir. It is also essential for muscle contraction, nerve transmission, blood clotting, and hormone signaling. When dietary calcium is inadequate, the body draws on bone, weakening it over time and raising osteoporosis and fracture risk.
Recommended intake (Dietary Reference Intakes; Institute of Medicine 2011, unchanged in the National Academies' 2019 summary tables):
- Adults 19–50: 1,000 mg/day.
- Women 51+ and men 71+: 1,200 mg/day (men 51–70 remain at 1,000 mg).
- Pregnancy and lactation (19+): 1,000 mg/day (1,300 mg/day at 14–18).
- Tolerable upper limit: 2,500 mg/day for adults 19–50; 2,000 mg/day for 51+.
Calcium absorption depends on adequate vitamin D (see Vitamin D). Rich sources include dairy, fortified plant milks, canned fish with bones, tofu set with calcium, and leafy greens. At-risk groups include postmenopausal women, older adults, and people avoiding dairy without fortified replacements. Weight-bearing and resistance exercise complements calcium and vitamin D in building and preserving bone (see Bone Tissue and Bone Health). Calcium is best obtained from food; supplements can fill genuine gaps, but total intake from food plus supplements should stay under the UL, the highest daily intake likely to pose no risk of adverse effects for almost everyone.
Key facts
- Most abundant body mineral; bone reservoir plus muscle/nerve/clotting roles.
- RDA 1,000 mg/day (19–50); 1,200 mg/day women 51+ and men 71+.
- Upper limit 2,500 mg/day (19–50), 2,000 mg/day (51+), from food plus supplements.
- Pregnancy/lactation (19+): 1,000 mg/day.
- Absorption requires vitamin D.
- At-risk: postmenopausal women, older adults, dairy-avoiders.
Connections
- Vitamin D — required for calcium absorption.
- Minerals — Overview (Magnesium, Zinc, and the Remaining Trace Minerals) — calcium among the key minerals.
- Prenatal & Postpartum (Redirect) — elevated needs in pregnancy/lactation.
- Bone Tissue and Bone Health — calcium's structural role.
Sources
- GuidelineInstitute of Medicine. Dietary Reference Intakes for Calcium and Vitamin D (2011) Published 2011-03-30 · DOI 10.17226/13050 · Accessed 2026-10-13
- GuidelineNational Academies of Sciences, Engineering, and Medicine. Dietary Reference Intakes for Sodium and Potassium (2019), Appendix J: Dietary Reference Intakes Summary Tables (RDAs/AIs and ULs for elements) Published 2019 · Accessed 2026-10-13
Corrections (1)
- 2026-10-13 — Verified the RDAs (1,000 mg/day adults 19–50 and men 51–70; 1,200 mg/day women 51+ and everyone 71+) and ULs (2,500 mg/day 19–50; 2,000 mg/day 51+) against the National Academies DRI summary tables (2019 compilation; the calcium values in that compilation come from the 2011 Calcium and Vitamin D report). Values unchanged; added the dated sources and the pregnancy/lactation RDA (1,000 mg/day at 19+). Reworded the unsourced 'very high supplemental doses confer no extra benefit' line to the UL definition the tables give. The NIH ODS fact sheet could not be retrieved for this check (site blocked automated access), so it is no longer cited.
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