Calcium

CautionSuggested

4 studies · 2 recommendations

Last updated: February 25, 2026

Caution1 studies

Calcium supplements show no clear colorectal cancer benefit alone

Despite observational data suggesting a protective effect, this meta-analysis of randomised trials found no significant reduction in colorectal cancer risk from calcium supplements alone, and a non-significant trend toward increased risk was observed.

Evidence

Calcium supplements and cancer risk : a meta-analysis of randomised controlled trials

Authors: Avenell, Alison, Bolland, Mark J, Bristow, Sarah M, Gamble, Greg D, Grey, Andrew, Maclennan, Graeme S, Reid, Ian R

Published: April 19, 2013

Meta-analysis of randomised placebo-controlled trials examined calcium supplementation (≥500 mg/d) without vitamin D on colorectal cancer risk. Trial-level data from 8 studies (n=9,863) showed no significant effect on colorectal cancer (relative risk 1.38, 95% CI 0.89–2.15, P=0.15). Patient-level analysis of 4 trials (n=7,221, median duration 3.5 years) similarly found no significant effect (hazard ratio 1.41, 95% CI 0.86–2.32, P=0.17). These findings contrast with observational studies suggesting protective effects, and the non-significant trend toward increased risk warrants caution when supplementing calcium without vitamin D for cancer prevention purposes.

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Suggested3 studies

Calcium supplementation linked to modest reduction in colorectal cancer risk

Three studies encompassing over 512,000 participants support a protective role for calcium against colorectal cancer. In the EPIC cohort of 477,312 participants with 4,517 colorectal cancer cases, a calcium-rich nutrient pattern reduced risk by 4% per standard deviation increase (HR 0.96, 95% CI: 0.93–0.99). The Norwegian NOWAC cohort of 35,525 women attributed 10.0% of colon cancer incidence to low calcium intake, though with wide confidence intervals. A systematic review of 105 clinical trials confirmed an association between calcium consumption and decreased colorectal cancer and adenomatous polyp incidence. The evidence spans two large prospective cohort studies and one systematic review, consistently pointing toward calcium's protective effect, though optimal dosing and supplementation duration remain to be established.

Evidence

The burden of colon cancer attributable to modifiable factors—The Norwegian Women and Cancer Study

Authors: Borch, Kristin Benjaminsen, Laaksonen, Maarit A., Licaj, Idlir, Lukic, Marko, Rylander, Charlotta, Weiderpass, Elisabete

Published: August 22, 2022

Among 35,525 women in the NOWAC cohort study, the population attributable fraction of colon cancer due to low calcium intake was 10.0% (95% CI −7.8% to 24.8%). The wide confidence interval crossing zero reflects uncertainty, but the point estimate suggests calcium intake may play a role in colon cancer prevention. Calcium was one of seven modifiable risk factors evaluated using a parametric piecewise constant hazards model with competing risk of death, collectively explaining 46.0% (95% CI 23.0%-62.4%) of colon cancer incidence.

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Revisión sistemática utilidad de asa y calcio con o sin vitamina d en la prevención de cáncer colorrectal y la recurrencia de pólipos adenomatosos en paciente con riesgo de padecer esta patología

Authors: Lopez Gomez, Mauricio Alejandro, Lopez Narvaez, Sara Belen

Published: July 5, 2016

A systematic review selected 105 clinical trials from databases spanning 1990 onward, evaluating calcium supplementation with and without vitamin D in patients with risk factors for colorectal cancer and adenomatous polyps. Exclusion criteria removed patients with existing colorectal cancer, Lynch syndrome, and familial adenomatous polyposis. After applying inclusion and exclusion criteria, qualifying literature, and eliminating duplicates, the 105 selected studies showed an association between calcium consumption and decreased incidence of colorectal cancer and adenomatous polyps. The review concluded that while protective effects were observed, further studies are needed to fully characterize the magnitude of risk reduction, optimal calcium dosing, and duration of supplementation.

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Main nutrient patterns and colorectal cancer risk in the European Prospective Investigation into Cancer and Nutrition study.

Authors: A Koushik, A Moskal, A O’Sullivan, Androniki Naska, Anna Winkvist, Anne Tjønneland, Antonia Trichopoulou, AS Yusof, Aurora Perez-Cornago, Aurélie Affret, Aurélie Moskal, Bas H Bueno-de-Mesquita, Camilla Plambeck Hansen, Carlotta Sacerdote, CD Davis, Christina Bamia, Christina C Dahm, CL Ulrey, Claire Cadeau, CM Ulrich, D Aune, Dagrun Engeset, DR Jacobs Jr, DR Jacobs Jr, DR Jacobs Jr, E De Stefani, E Riboli, E Riboli, Elena Molina-Portillo, Emily Sonestedt, Eva Ardanaz, F Bravi, F Turati, FB Hu, FB Hu, G Nicolas, G Randi, GC Chen, Genevieve Buckland, Giovanna Masala, Graham Byrnes, Guri Skeie, H Freisling, H Freisling, Heather Ward, Heiner Boeing, Heinz Freisling, Idlir Licaj, Inge Huybrechts, J Ferlay, JC Hersey, José M Huerta Castaño, José R Quirós, JP Higgins, Kay-Tee Khaw, Khalid Iqbal, Konstantinos K Tsilidis, Kristina EN Petersen, M Huncharek, M Song, Marc J Gunter, Maria Santucci de Magistris, Marie-Christine Boutron-Ruault, Mazda Jenab, Michael T Fahey, MK Kim, N Slimani, N Slimani, Nada Assi, Nadia Slimani, Nick Wareham, P Ferrari, PE Miller, Petra H Peeters, Pietro Ferrari, Pilar Amiano, PM Rothwell, R Johnson, RM van Dam, Robin Myte, Rosario Tumino, S Greenland, S Zschabitz, SA Bingham, SA Lamprecht, Sabina Sieri, SE McCann, SJ Eussen, T Norat, Tilman Kühn, TT Fung, Ulrika Ericson, Verena Katzke, WC Willett, WC Willett, WL Stone, XH Zhang

Published: January 1, 2016

Among 477,312 EPIC study participants with 4,517 incident colorectal cancer cases over an average 11-year follow-up, a nutrient pattern characterized by total protein, riboflavin, phosphorus, and calcium demonstrated a statistically significant inverse association with colorectal cancer risk (HR per 1 standard deviation = 0.96, 95% CI: 0.93–0.99), equating to a 4% risk reduction per standard deviation increase. This analysis used multivariate Cox proportional hazards models adjusted for established colorectal cancer risk factors, with nutrient intakes estimated from validated dietary questionnaires across multiple European countries.

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