Supplement evidence

005 / 575Mineral

Calcium

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The short answer

Meeting calcium needs when food intake is inadequate, including as part of some osteoporosis plans.

Evidence and scope: Conditional or population-specific
This status does not grade the ingredient for every goal, outcome, or person.
Important limitation: Fracture prevention in generally healthy community-dwelling adults is mixed and depends on context.
Before deciding: Excess can cause constipation or kidney stones and can interfere with thyroid medicine and some antibiotics.

01 / PRACTICAL GUIDE

Dose, absorption, and combinations

These are indication-specific reference or studied ranges—not a personalized prescription. Start with the objective, then check the form, label, medicines, and health conditions.

Reference range by objective

Meeting usual needsTotal food plus supplements generally targets 1,000–1,200 mg/day; split supplemental doses to 500 mg or less

Reference or studied range—not a personalized prescription. The product label or a clinician may specify a different dose.

Dose source ↗

More is not automatically better. A clinician or product label may specify a different amount.

Absorption / solubilityFormulation-dependent

Not usefully classified as a fat- or water-soluble vitamin; absorption depends on the salt, extract, delivery system, and meal.

How it is commonly taken

Calcium carbonate needs food; calcium citrate is less meal-dependent.

Do not combine casually

Separate from levothyroxine, iron, and some antibiotics; kidney-stone risk and hypercalcemia require review.

Dose and use source ↗

Dose and use links lead to primary or official source material. Search links are discovery tools, not proof that every returned paper applies.

02 / EVIDENCE

What the research says

We keep supportive, mixed, negative, safety, and contextual findings together. The headline never replaces the underlying papers.

5research papers in this ledger

26unique primary studies represented

60,193unique participants represented

These are audited counts for this JIVANA collection, not search-result totals. Participants are counted once when multiple papers use the same cohort; review papers are not added again to participant totals.

Open the research timelineResearch timeline

Entries are ordered by publication year. A study period appears only when the source reports it.

2026

Does not support the tested claimPMID 42161415 · PROSPERO CRD42023483915

Calcium, vitamin D, or combined supplementation to prevent fractures and falls

Across mostly community-dwelling adults not at high fracture risk, calcium alone or with vitamin D produced little to no clinically meaningful fracture or fall benefit.

Published: 2026n=60,193 participants26 primary studies represented

Study design and methods

Design: Systematic review and meta-analysis of randomized trials
Population: 60,193 adults in 11 calcium-only and 15 calcium-plus-vitamin-D trials relevant to calcium
Intervention: Calcium alone or calcium plus vitamin D versus placebo or no treatment
Outcome: Fractures and falls

Funding or conflict note: The authors reported no industry support for the review.

Open research record ↗

2023

Mixed or qualifiedPMID 37181938

Calcium Supplements and Risk of CVD

No significant excess in coronary disease, stroke, or all-cause mortality was detected. Because these trials overlap other calcium reviews, this is context-only.

Published: 2023

Study design and methods

Design: Meta-analysis of 11 placebo-controlled randomized trials
Population: 55,438 participants in calcium-only or calcium-plus-vitamin-D comparisons
Intervention: Calcium alone or with vitamin D versus placebo
Outcome: Coronary disease, stroke, and all-cause mortality

Open research record ↗

2021

Safety signalPMID 33530332

Calcium Supplements and Risk of Cardiovascular Disease

This analysis reported a roughly 15% relative increase in cardiovascular events, but overlapping later analyses reached a different conclusion. It is excluded from totals.

Published: 2021

Study design and methods

Design: Meta-analysis of 13 double-blind placebo-controlled trials
Population: 43,178 adults, especially healthy postmenopausal women
Intervention: Calcium supplements versus placebo
Outcome: Cardiovascular and coronary heart disease events

Funding or conflict note: The authors declared no conflicts of interest.

Open research record ↗

2006

Mixed or qualifiedPMID 16481635 · NCT00000611

Calcium plus vitamin D supplementation and the risk of fractures

Hip bone density improved slightly, but fractures did not fall significantly in intention-to-treat analyses and kidney stones increased. Already represented in the 2026 review totals.

Published: 2006Duration: Average 7 years

Study design and methods

Design: Randomized placebo-controlled trial
Population: 36,282 generally healthy postmenopausal women aged 50–79
Intervention: 1,000 mg elemental calcium plus 400 IU vitamin D₃ daily versus placebo
Outcome: Bone density, fractures, and kidney stones

Open research record ↗

1992

Supports a specific usePMID 1331788

Vitamin D3 and calcium to prevent hip fractures in elderly women

Fractures fell in this older institutional population, a result that should not be generalized to lower-risk community-dwelling adults. The trial is already represented in the 2026 review totals.

Published: 1992Duration: 18 months

Study design and methods

Design: Controlled clinical trial
Population: 3,270 ambulatory women living in institutions, mean age 84
Intervention: 1.2 g elemental calcium plus 800 IU vitamin D₃ daily versus placebo
Outcome: Hip and nonvertebral fractures

Open research record ↗

Unscreened discovery appendix—not evidence974 candidate publicationsSearch run: Aug 21, 2026

Complete for the displayed PubMed query at the search timestamp—not for all databases or every possible synonym. Candidates can be irrelevant, duplicate the same study, or report negative findings. They are never summed as evidence or participants until screened.

03 / SOURCES

Start with the source material

Official evidence overviewNIH Office of Dietary Supplements Live PubMed discovery searchNational Library of Medicine

The live search is for discovery only. Search-result counts change and are not included in the audited totals above.

Recent PubMed discovery recordsDirect links to the first 12 records returned by the reproducible search. These are discovery candidates—not reviewed summaries or a count of supportive findings.

04 / EXPERT CONTEXT

Expert context—not evidence

Expert positions are dated context—not scientific evidence. They never raise the evidence status or become consensus by repetition.

No direct, source-verified endorsement is currently recorded. Research authorship or discussion alone is not treated as endorsement.