by EBSCO CAM Review Board


Calcium is an essential nutrient that is found in dairy products, such as milk and cheese. It has been used to lower blood pressure, promote weight loss, and improve bone strength. Calcium can be taken as a pill or powder.


500 milligrams 1 to 2 times daily.

What Research Shows

Likely Effective

  • Colorectal adenomas—likely to reduce occurrence and promote healing E1, E2
  • Hypercalcemia after thyroidectomy—likely to prevent hypercalcemia after surgery I1, I2
  • Hyperlipidemia —likely to help control cholesterol and blood fat levels G1
  • Osteoporosis —likely to prevent fracture and promote bone health when taken with vitamin D K1
  • Preeclampsia —likely to reduce risk L1-L5
  • Weight loss—likely to reduce body weight in people with normal BMI O1

May Be Effective

  • Blood pressure —may lower blood pressure in people with normal blood pressure A1
  • Bone mineral density—may have small increases in bone mineral density that is unlikely to lead to a reduction in fracture risk B1, B2
  • Fall prevention—may prevent falls in older adults, especially when used with vitamin D F1-F3
  • Premenstrual syndrome (PMS) —may reduce symptoms M1, M2

May Not Be Effective

  • Cognitive function—may not ease symptoms D1

Unlikely to Be Effective

  • Cardiovascular events—increases the risk of cardiovascular events and heart attack C1, C2
  • Stroke—increases the risk of stroke N1

Not Enough Data to Assess

  • Hypertensive disorders of pregnancy H1
  • Obesity J1

Editorial process and description of evidence categories can be found at EBSCO NAT Editorial Process.

Editorial process and description of evidence categories can be found at EBSCO NAT Editorial Process.

Safety Notes

It is likely safe to take calcium in small doses for a short time. High doses of calcium may not be safe. Not enough studies have been done to say whether it is safe to take for a long period


Talk to your doctor about any supplements or therapy you would like to use. Some can interfere with treatment or make conditions worse such as:

  • People with heart problems should talk to their doctors before taking calcium. It may worsen symptoms.


REFA Blood Pressure

REFA1 Cormick G, Ciapponi A, et al. Calcium supplementation for prevention of primary hypertension. Cochrane Database Syst Rev. 2015 Jun 30;(6):CD010037.

REFB Bone Mineral Density

REFB1 Hofmeyr GJ, Belizán JM, et al. Low-dose calcium supplementation for preventing pre-eclampsia: a systematic review and commentary. BJOG. 2014 Jul;121(8):951-957. B2. Tai V, Leung W, et al. Calcium intake and bone mineral density: systematic review and meta-analysis. BMJ. 2015 Sep 29;351:h4183.

REFC Cardiovascular Events

REFC1 Mao PJ, Zhang C, et al. Effect of calcium or vitamin D supplementation on vascular outcomes: a meta-analysis of randomized controlled trials. Int J Cardiol. 2013 Oct 30;169(2):106-111.

REFC2 Reid IR, Bristow SM, et al. Cardiovascular complications of calcium supplements. J Cell Biochem. 2015 Apr;116(4):494-501.

REFD Cognitive Function

REFD1 Rutjes AW, Denton DA, et al. Vitamin and mineral supplementation for maintaining cognitive function in cognitively healthy people in mid and late life. Cochrane Database Syst Rev. 2018 Dec 17;12:CD011906.

REFE Colorectal Adenomas

REFE1 Bonovas S, Fiorino G, et al. Calcium supplementation for the prevention of colorectal adenomas: A systematic review and meta-analysis of randomized controlled trials. World J Gastroenterol. 2016;22(18):4594-4603.

REFE2 Veettil SK, Ching SM, et al. Effects of calcium on the incidence of recurrent colorectal adenomas: A systematic review with meta-analysis and trial sequential analysis of randomized controlled trials. Medicine (Baltimore). 2017 Aug;96(32):e7661.

REFF Fall Prevention

REFF1 Bolland MJ, Leung W, et al. Calcium intake and risk of fracture: systematic review. BMJ. 2015 Sep 29;351:h4580.

REFF2 Wu H, Pang Q. The effect of vitamin D and calcium supplementation on falls in older adults: A systematic review and meta-analysis. Orthopade. 2017 Sep;46(9):729-736.

REFF3 Tricco AC, Thomas SM, et al. Comparisons of Interventions for Preventing Falls in Older Adults: A Systematic Review and Meta-analysis. JAMA. 2017 Nov 7;318(17):1687-1699.

REFG Hyperlipidemia

REFG1 Chen C, Ge S, et al. The Effects of Dietary Calcium Supplements Alone or With Vitamin D on Cholesterol Metabolism: A Meta-Analysis of Randomized Controlled Trials. J Cardiovasc Nurs. 2017;32(5):496-506.

REFH Hypertensive Disorders of Pregnancy

REFH1 Hofmeyr GJ, Manyame S. Calcium supplementation commencing before or early in pregnancy, or food fortification with calcium, for preventing hypertensive disorders of pregnancy. Cochrane Database Syst Rev. 2017 Sep 26;9:CD011192.

REFI Hypocalcemia after Thyroidectomy

REFI1 Alhefdhi A, Mazeh H, et al. Role of postoperative vitamin D and/or calcium routine supplementation in preventing hypocalcemia after thyroidectomy: a systematic review and meta-analysis. Oncologist. 2013;18(5):533-542.

REFI2 Xing T, Hu Y, et al. Role of oral calcium supplementation alone or with vitamin D in preventing post-thyroidectomy hypocalcaemia: A meta-analysis. Medicine (Baltimore). 2019 Feb;98(8):e14455.

REFJ Obesity

REFJ1 Onakpoya IJ, Perry R, et al. Efficacy of Calcium Supplementation for management of overweight and obesity: systematic review of randomized clinical trials. Nutr Rev. 2011;69(6):335-343.

REFK Osteoporosis

REFK1 Weaver CM, Alexander DD, Calcium plus vitamin D supplementation and risk of fractures: an updated meta-analysis from the National Osteoporosis Foundation. Osteoporosis Int. 2016;27(1):367-376.

REFL Preeclampsia

REFL1 Imdad A, Jabeen A, et al. Role of calcium supplementation during pregnancy in reducing risk of developing gestational hypertensive disorders: e meta-analysis of studies from developing countries. BMC Public Health. 2011;11(3):S18.

REFL2 Buppasiri P, Lumbiganon P, et al. Calcium supplementation (other than for preventing or treating hypertension) for improving pregnancy and infant outcomes. Cochrane Database Syst Rev. 2015 Feb 25;(2):CD007079.

REFL3 Tang R, Tang IC, et al. Limited evidence for calcium supplementation in preeclampsia prevention: a meta-analysis and systematic review. Hypertens Pregnancy. 2015 May;34(2):181-203.

REFL4 Khaing W, Vallibhakara SA, et al. Calcium and Vitamin D Supplementation for Prevention of Preeclampsia: A systematic Review and Network Meta-Analysis. Nutrients. 2017;9(10):E1141.

REFL5 Hofmeyr GJ, Lawrie TA, et al. Calcium supplementation during pregnancy for preventing hypertensive disorders and related problems. Cochrane Database Syst Rev. 2018;10:CD001059.

REFM Premenstrual Syndrome

REFM1 Ghanbari Z, Haghollahi F, et al. Effects of calcium supplementation therapy in women with premenstrual syndrome. Taiwan J Obstet Gynecol. 2009;48(2):124-129.

REFM2 Shehata NA. Calcium versus oral contraceptive pills containing drospirenone for the treatment of mild to moderate premenstrual syndrome: a double blind randomized placebo controlled trial. Eur J Obstet Gynecol Reprod Biol. 2016;198:100-104.

REFN Stroke

REFN1 Mao PJ, Zhang C, et al. Effect of calcium or vitamin D supplementation on vascular outcomes: a meta-analysis of randomized controlled trials. Int J Cardiol. 2013 Oct 30;169(2):106-111.

REFO Weight Loss

REFO1 Li P, Fan C, et al. Effects of calcium supplementation on body weight: a meta-analysis. Am J Clin Nutr. 2016 Nov;104(5):1263-1273.

Revision Information

  • Reviewer: EBSCO CAM Review Board
  • Review Date: 07/2019
  • Update Date: 03/20/2020