Calcium Intake Linked to Reduced Colorectal Cancer Risk, Study Finds

Increasing calcium intake may reduce avoidable colorectal cancer (CRC) risk, with reduced risks observed across tumor sites and sources of calcium, according to one study.¹

Higher calcium intake was associated with reduced colorectal cancer (CRC) risk across tumor sites and calcium sources, according to one study. | Image credit: tima-miroshnichenko - pexels.com

This cohort study is published in JAMA Network Open.

“To our knowledge, this cohort study investigating calcium source and tumor site was the most extensive analysis to date on the association of calcium intake with incident CRC,” the researchers wrote. “With 10,618 first primary CRC cases diagnosed over 23 years of follow-up, we explored calcium-CRC associations across population subgroups that have been identified as having lower calcium intake in the general US population, namely women and racial and ethnic groups.”

Although there is no sure way to prevent CRC, studies have identified possible ways to help lower the risk, including increasing calcium intake to lower the risk of CRC adenomas.² One study found that among those with the highest calcium intake, CRC risk was significantly reduced in men (OR, 0.16; 95% CI, 0.11-0.24) and women (OR, 0.16; 95% CI, 0.09-0.29).

In the current study, the researchers aimed to examine the association between calcium intake and CRC risk, noting the source of calcium and tumor site across racial and ethnic groups.¹

The study utilized data from the National Institutes of Health–AARP Diet and Health Study, which enrolled participants aged 50 to 71 years at baseline between October 1995 and May 1996. Eligible participants were those who self-reported good health and had neither extremely high nor low caloric or calcium intake. The cohort was followed until the occurrence of their first primary cancer diagnosis, death, loss to follow-up, or the study's end on December 31, 2018. Data analysis was conducted from April 2022 to April 2024, focusing on health outcomes over the study period.

A total of 471,396 patients were identified as cancer-free at baseline, with a mean (SD) age of 64 (5.4) years, and 59.5% were male.

Over a median (IQR) follow-up of 18.4 (9.2-22.5) years and a total of 7,339,055 person-years, 10,618 first primary CRC cases were identified. Calcium intake varied widely across quintiles, with the lowest quintile (Q1) showing an average of 401 mg/d for women and 407 mg/d for men, and the highest quintile (Q5) showing 2056 mg/d for women and 1773 mg/d for men. Calcium sources included dairy (42.1%), nondairy (34.2%), and supplements (23.7%).

Higher total calcium intake, particularly in the highest quintile (Q5), was associated with a significantly lower risk of CRC (HR, 0.71; 95% CI, 0.65-0.78; P < .00). This association was consistent across different sources of calcium and tumor sites.

Among non-Hispanic Black participants, calcium intake also varied between the lowest and highest quintiles (382 mg/d to 1916 mg/d), but no significant association was observed between total calcium intake and CRC risk (HR, 0.60; 95% CI, 0.32-1.13; P = .12). Therefore, no evidence of effect modification by race and ethnicity was observed.

However, the researchers noted some limitations. First, dietary information was collected at baseline only, which limited the researchers’ ability to assess changes in calcium intake over time. Second, they noted the limited statistical power due to smaller case numbers, which prevented stratified analyses by sex or race and ethnicity.

Despite these limitations, the researchers believe the study highlights the association between increased calcium intake and reduced CRC risk.

“While calcium intake may vary by race and ethnicity, the potential for calcium to play a role in CRC prevention appeared to be consistent across racial and ethnic groups; still, research in racial and ethnic minority populations is needed,” the researchers wrote. “Increasing calcium intake, particularly among population subgroups with lower intakes, may be associated with a reduction in avoidable differences in CRC cancer risk.”

References

1. Zouiouich S, Wahl D, Liao LM, et al. Calcium intake and risk of colorectal cancer in the NIH-AARP Diet and Health study. JAMA Netw Open. 2025;8(2):e2460283. doi:10.1001/jamanetworkopen.2024.60283

2. Han C, Shin A, Lee J, et al. Dietary calcium intake and the risk of colorectal cancer: a case control study. BMC Cancer. 2015;15:966. doi:10.1186/s12885-015-1963-9