Calcium and cancer prevention
Calcium, the most abundant mineral in the body, plays a crucial role in various physiological functions, including muscle contraction and nerve impulse transmission. It is primarily obtained through diet, with dairy products being significant sources. Ongoing research has explored the relationship between calcium intake and cancer prevention, particularly concerning colorectal and breast cancers. Some studies suggest that higher calcium intake may reduce the risk of colorectal cancer, although findings are not universally conclusive. For breast cancer, evidence indicates that combined intake of calcium and vitamin D may lower risks for premenopausal women, yet results differ in postmenopausal groups. In contrast, increasing calcium intake in men has been linked to a potential rise in prostate cancer risk, though this association requires further investigation. Given these mixed outcomes, health organizations emphasize the importance of a balanced diet and lifestyle choices in cancer prevention, while recognizing that the role of calcium remains complex and not fully understood.
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Subject Terms
Calcium and cancer prevention
ALSO KNOWN AS: Calcium carbonate, calcium citrate, calcium phosphate
DEFINITION: Calcium is the most abundant mineral in the body. About 1 percent of calcium is found circulating in the blood, while the remaining 99 percent is stored in bones and teeth. Calcium must be obtained from the diet. It is found primarily in dairy products and is sold as a dietary supplement.
Cancers treated or prevented:Colorectal cancer, breast cancer
Delivery routes: Oral tablet
How this substance works: Circulating levels of calcium help control metabolic events such as muscle contraction and nerve impulse transmission. In healthy people, the amount of calcium in the blood is kept within narrow limits by hormonal regulation. Calcium also helps to build strong bones and delay bone loss caused by aging (osteoporosis). A 2024 article by the Mayo Clinic cited calcium recommendations found in the National Institute of Health (NIH). These called for varying intakes of calcium based on age. For a child under six months old, the NIH called for a daily dosage of 200 milligrams (mg). A senior 71 and older was recommended to consume 1,200 mg. of calcium daily. Calcium-rich foods included yogurt, where an 8-ounce serving provided 415 mg. of calcium. Nonfat milk contained 299 mg per 8 ounces. Fortified orange juice has 300 mg. per 8 ounces. A 2023 study published by Dartmouth University asserted that 2000 mg. was the recommended upper limit for calcium intake.
Animal studies and several human observational and research studies have found that increased calcium intake protects against colorectal cancer. The reason for this protective effect is not understood, and not all studies are conclusive. In 2007, the Women’s Health Initiative study of more than 36,000 women aged fifty to seventy-nine found no effect of calcium on colorectal cancer.
Other animal studies have suggested that calcium may protect against breast cancer. In 2007, a peer-reviewed study of 10,500 premenopausal women found that when the intakes of calcium and vitamin D were simultaneously increased for an extended period, the risk of developing breast cancer was reduced by almost one-third. This effect was not observed in postmenopausal women. Other studies appear to contradict these findings. A 2016 study by Cambridge University asserted an inconclusive relationship between calcium intake and reduced breast cancer risk.
Side effects: Complicating the situation with calcium is evidence that increasing calcium intake in men in amounts ranging from 600 to 2,000 milligrams or more per day may increase the risk of developing prostate cancer. This is not, however, a consistent finding. As of mid-2020, more rigorous studies were required.
Many tumors that invade bone release stored calcium and cause the blood calcium level to increase independent of dietary intake. This condition, called hypercalcemia, is the most common life-threatening metabolic disorder associated with cancer.
In the mid-2020s, since the association between calcium and cancer remains unclear, the American Cancer Society(ACS) has observed trends and issued recommendations. Colorectal cancer remains a deadly occurrence as 152,810 new instances were expected for 2024, with 53,010 expected fatalities. Colorectal cancers were projected to rise among younger Americans, with a 1-2% annual increase among those younger than 55. Survival rates were also expected to increase. On a positive note, the ACS commented on the control people have on lifestyle choices, which can help reduce the risks of colorectal cancers. These include refraining from smoking, excessive intake of red meat, limiting alcohol consumption, and promoting diets containing fruits, vegetables, and grains.
Bibliography
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"Calcium." MedlinePlus, 14 May 2024, medlineplus.gov/calcium.html. Accessed 25 June 2024. "Calcium and Vitamin D for Improving Bone Health in Healthy Premenopausal Women." Cochrane, 21 Jan 2023, www.cochrane.org/CD012664/MUSKEL‗calcium-and-vitamin-d-improving-bone-health-healthy-premenopausal-women. Accessed 25 June 2025.
"Calcium Intake and Absorption: Are You Getting Enough?" Mayo Clinic, 29 Feb. 2024, www.mayoclinichealthsystem.org/hometown-health/speaking-of-health/calcium-intake-and-absorption. Accessed 25 June 2024.
"Cancer Prevention Overview (PDQ®)–Health Professional Version." National Cancer Institute, 6 Mar. 2024, www.cancer.gov/about-cancer/causes-prevention/hp-prevention-overview-pdq. Accessed 25 June 2024.
Kelce, Diane. "Calcium and Cancer: Is There a Connection?" Dartmouth Cancer Center, 17 Apr. 2023, cancer.dartmouth.edu/stories/article/calcium-and-cancer-there-connection. Accessed 25 June 2024.
Dietary Reference Intakes for Calcium and Vitamin D, rev. ed., Washington, DC, National Academy of Sciences, 2011.
Zeratsky, Katherine. "When Should I Take Calcium Supplements? Does It Matter What Time?" Mayo Clinic, 20 May 2023, www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/expert-answers/calcium-supplements/faq-20058238. Accessed 25 June 2024.
Zhaojun, Mei, et. al. "The Role of Vitamin D in Menopausal Women’s Health." Frontiers in Physiology, 12 June 2023, www.ncbi.nlm.nih.gov/pmc/articles/PMC10291614. Accessed 25 June 2024.