Meta-analysisindependent cross-checkabstract checked I-SUP-111 standard review
Calcium from food vs pills and heart disease
The Evidence and Controversy Between Dietary Calcium Intake and Calcium Supplementation and the Risk of Cardiovascular Disease: A Systematic Review and Meta-Analysis of Cohort Studies and Randomized Controlled Trials.
Overview
Yang C et al.. J Am Coll Nutr 2020 · PMID 31625814 · DOI 10.1080/07315724.2019.1649219
Calcium from food was not linked to heart disease, but calcium pills were linked to about 14% more heart attacks in trials.
Does the study support the specific claim? Partly · Methodological quality: moderate
Plain-language summary
Study explained simply
- What did the researchers want to find out?
To compare food calcium and calcium pills for heart risk.
- How was the study done?
Meta-analysis of cohorts and trials.
- How many people, animals or samples were studied?
26 cohorts, 16 trials.
- What was actually found?
Food calcium neutral; pills linked to more heart attacks.
- How large was the observed effect?
MI RR 1.14 (1.05-1.25).
- What do the results mean in everyday life?
If calcium is needed, food sources are not linked to heart risk.
- What are the study's limitations?
One reported interval looks erroneous; overlapping data.
- What does it say about Elawady's specific claim?
Supports the direction of C-SUP-04.
- Do the results apply to Germany and Europe?
Applicable.
- What can explicitly not be concluded from this study?
Cannot prove that calcium pills cause heart attacks.
Scientific in-depth review
1. Full reference
- Authors
- Yang C et al.
- Journal
- J Am Coll Nutr
- Year
- 2020
- Identifier
- PMID 31625814 DOI 10.1080/07315724.2019.1649219
- Verification
- verified – PubMed efetch 2026-10-26; Crossref works API 2026-10-26
- Retracted
- no
- Corrections
- none
- Extent checked
- abstract only
- Conflicts of interest and funding
No COI statement in PubMed record
2. Research question
Are dietary calcium and calcium supplements associated with CVD?
3. Study design and population
- Study design
- Meta-analysis – Systematic review and meta-analysis of prospective cohorts and RCTs
- Population
Adults in cohorts and RCTs
- Country
Multinational
- Period
Search to March 2019
- Sample size
26 cohorts and 16 RCTs
- Inclusion and exclusion criteria
RCTs and prospective cohorts with calcium intake and CVD outcomes
4. Methods and endpoints
- Exposure / intervention
Dietary calcium; calcium supplements with or without vitamin D
- Comparator
Lower intake / placebo
- Endpoints
CVD, CHD, MI, stroke
- Statistical methods
Random-effects meta-analysis
5. Actual results
- Results
Cohorts: dietary calcium 200-1500 mg/d not associated with CVD (RR 0.96, 0.87-1.05), CHD (0.98) or stroke (0.94). RCTs: calcium supplements CHD RR 1.08 (1.02-1.22); calcium alone CHD 1.20 (1.08-1.33); MI 1.14 (1.05-1.25); calcium alone MI 1.21 (1.08-1.35).
- Absolute risks
not reported in abstract
- Authors' conclusion
Dietary calcium does not increase CVD risk, while calcium supplements might raise CHD risk, especially MI.
6. Strengths
- Separates dietary and supplemental calcium
7. Weaknesses
- The CHD estimate 1.08 (1.02-1.22) is not log-symmetric, suggesting a reporting error (stats/C-SUP-04_calcium.py)
- Overlapping trials with other meta-analyses
8. Risk of bias
- Orienting tool
- AMSTAR 2
- Type of assessment
- simplified assessment (abstract only)
- Full formal assessment
- no
- Overall risk of bias
- some concerns
- Rationale
Abstract only; possible typographical error in one CI.
9. Assessment of the statistical interpretation
Upper log distance about 2.1 times the lower for the CHD estimate - implausible for a ratio CI; MI estimates are internally consistent.
10. Relevance to the specific claim
Supports a modest MI excess with calcium supplements, larger with calcium alone; not for dietary calcium.
11. Independent contrary findings
I-SUP-112 Sim 2023; I-SUP-06 Chung 2016.
12. Transferability to Germany and Europe
Applicable.
13. Overall methodological judgement
Supportive but overlapping and partly inconsistent reporting.
| Multidimensional assessment | |
|---|---|
| Authenticity of the source | verified |
| Methodological quality | moderate |
| Risk of bias | some concerns |
| Precision of results | moderate |
| Directness | direct |
| Reproducibility | partly replicated |
| Consistency with the overall evidence | inconsistent |
| Regional transferability | high |
| Adequacy of the interpretation (by the archive) | not applicable |
14. Open questions
Clarification of the CHD CI.