Calcium Supplements, Heart Disease and Kidney Stones: What Studies Found
What meta-analyses and cohort studies found about calcium supplements, heart attacks and kidney stones, and why calcium from food and from pills may not behave the same way.
Content last updated . This page has not been medically reviewed.
Calcium supplements and heart disease
| Question | What the source found | Strength of evidence |
|---|---|---|
| Calcium supplements without vitamin D, heart attack | 2010 BMJ meta-analysis of 15 placebo-controlled trials (supplements of 500 mg or more a day, participants mean age over 40, over a year). In five trials with patient-level data (8,151 people), heart attack hazard ratio 1.31 (95% CI 1.02 to 1.67). Trial-level data: risk ratio 1.27 (1.01 to 1.59). [1] | Mixed |
| Calcium supplements, cardiovascular disease | 2021 meta-analysis of 13 double-blind placebo-controlled trials: about 15% higher cardiovascular risk (RR 1.15, 1.06 to 1.25), specifically in healthy postmenopausal women. [2] | Mixed |
| Dietary calcium | 2020 review of 26 cohort studies: dietary calcium of 200-1,500 mg a day did not change risk of cardiovascular disease (RR 0.96, 0.87 to 1.05), coronary disease or stroke. [5] | Observational; no association found |
| Supplements in the same 2020 review | Pooled trials: coronary heart disease risk up 8% overall and 20% with calcium alone; heart attack up 14%. The authors concluded supplements might raise coronary risk. [5] | Mixed |
How to read this: the abstracts we read do not say what each trial was designed to study, so we cannot say whether heart events were a main target. Proper evidence not found on that point (we searched PubMed on 2026-10-22 and read the abstracts cited here). Different reviews pool different trials, so results disagree on size. None of these studies shows that food calcium harms the heart. The 2020 review found no effect of dietary calcium. [5]
Calcium and kidney stones
| Question | What the source found | Strength of evidence |
|---|---|---|
| Dietary calcium, men without stones | 1993 cohort of 45,619 men aged 40-75 over four years: highest versus lowest fifth of dietary calcium, relative risk 0.56 (0.43 to 0.73), 0.66 (0.49 to 0.90) after further adjustment. [3] | Observational |
| Dietary calcium, stone formers | 2022 Mayo Clinic study of 411 first-time symptomatic stone formers and 384 controls: lower dietary calcium was linked to higher odds of a stone, and to recurrence. [6] | Observational |
| Calcium plus vitamin D3 supplement | Women's Health Initiative: 36,282 postmenopausal women, 1,000 mg elemental calcium as carbonate plus 400 IU vitamin D3 daily, about 7 years; kidney stones hazard ratio 1.17 (1.02 to 1.34). [4] | Evidence of harm in that trial |
| Task force view | The USPSTF found adequate evidence that vitamin D plus calcium supplementation increases kidney stones. [7] | Evidence of harm |
Why food and pills may differ: calcium in the gut can block other substances that lead to stones. [8] The US National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) tells people who had stones to ask a clinician which type they had and how much calcium they should eat. [8] The NHS lists getting enough calcium in the diet among its stone-prevention points and says not to change diet without speaking to a doctor. [9] MedlinePlus says higher calcium over a long time raises stone risk in some people. [10] The studies above do not tell us how timing or form (carbonate, citrate) changes stone risk; Proper evidence not found in the sources we read. See Minerals and kidney stones.
Frequently asked questions
Do calcium supplements cause heart attacks?
A 2010 BMJ meta-analysis reported more heart attacks with calcium supplements without vitamin D. [1] Other reviews also reported higher risk, but the question is not settled. [5]
Is calcium from food bad for the heart?
In a 2020 review of cohort studies, dietary calcium of 200 to 1,500 mg a day did not change cardiovascular risk. [5]
Does calcium cause kidney stones?
Calcium from food was linked to fewer stones in a large cohort. [3] A supplement trial in postmenopausal women reported more stones with calcium plus vitamin D. [4]
I have had kidney stones. Should I avoid calcium?
Not automatically. NIDDK says to ask a clinician which type of stone you had and how much calcium you should eat. [8]
Who should ask a clinician before taking calcium?
Anyone with kidney disease, stones, heart disease, an overactive parathyroid gland or on thiazide diuretics or lithium. [11]
More details: evidence, limits and cautions
The details behind this page: cautions, limits of the evidence and where sources disagree. Open any note to read it.
How to read the evidence labels
Labels used on this page: mixed (studies disagree or are limited), insufficient and evidence of harm (a trial reported more of an outcome). Observational means researchers watched what people ate or took; a randomized trial assigns people by chance and is better at showing cause.
Limits and uncertainty
- Heart: some confidence intervals sit close to 1, for example 1.01 to 1.59. [1] The sources we read do not identify who, if anyone, is at risk.
- Stones: cohorts rely on food questionnaires, and people with stones may change their diet.
- The 2010 meta-analysis covered calcium without vitamin D, while the Women's Health Initiative trial gave calcium with vitamin D3. [1][4] We do not carry findings from one to the other.
Safety and who should ask a clinician
- Kidney disease, kidney stones, an overactive parathyroid gland and some medicines such as thiazide diuretics and lithium can raise blood calcium; see Too much calcium. [11]
- People with known heart disease, stones or kidney problems should ask a clinician before starting calcium; do not stop a prescribed medicine on your own.
- Medicine interactions: Medication interactions.
- Pregnancy and children: Pregnancy and breastfeeding.
- Check product quality: Quality testing and certifications.
Main page: Calcium.
References
- Bolland MJ et al. BMJ 2010;341:c3691. Effect of calcium supplements on risk of myocardial infarction and cardiovascular events: meta-analysis. Read 2026-10-22.
- Myung SK et al. Nutrients 2021;13(2):368. Calcium supplements and risk of cardiovascular disease: a meta-analysis of clinical trials. Read 2026-10-22.
- Curhan GC et al. N Engl J Med 1993;328(12):833-838. A prospective study of dietary calcium and other nutrients and the risk of symptomatic kidney stones. Read 2026-10-22.
- Jackson RD et al. N Engl J Med 2006;354(7):669-683. Calcium plus vitamin D supplementation and the risk of fractures. Read 2026-10-22.
- Yang C et al. J Am Coll Nutr 2020;39(4):352-370. The evidence and controversy between dietary calcium intake and calcium supplementation and the risk of cardiovascular disease. Read 2026-10-22.
- Chewcharat A et al. Mayo Clin Proc 2022;97(8):1437-1448. Dietary risk factors for incident and recurrent symptomatic kidney stones. Read 2026-10-22.
- US Preventive Services Task Force. JAMA 2018;319(15):1592-1599. Vitamin D, calcium, or combined supplementation for the primary prevention of fractures in community-dwelling adults. Read 2026-10-22.
- NIDDK, Eating, Diet and Nutrition for Kidney Stones (last reviewed May 2017). Read 2026-10-22.
- NHS, Kidney stones. Read 2026-10-22.
- MedlinePlus Medical Encyclopedia, Calcium in diet (review date 1/21/2025). Read 2026-10-22.
- MedlinePlus Medical Encyclopedia, Hypercalcemia. Read 2026-10-22.