- Vitamin D and calcium supplementation may reduce risk of cancer but increase risk of cardiovascular disease, new study shows.
- The study, which looked at postmenopausal women, showed that the combination of supplements had no effect on death from any cause.
- Experts explain the findings.
Calcium and vitamin D supplements are often recommended for postmenopausal women to prevent bone loss. New research shows that it may do even more, reducing the risk of cancer. But, could it also increase the risk of cardiovascular disease?
A study published in Annals of Internal Medicine analyzed data from the Women’s Health Initiative trial, which looked into the effects of taking calcium and vitamin D supplements in more than 36,000 postmenopausal women.
Researchers found that taking calcium and vitamin D supplements lowered a woman’s long-term risk of dying from cancer by 7%, but increased the risk of death due to heart disease by 6%. The study also found that overall, the combination of supplements had no significant effect on early death overall.
Many people know the link between calcium and how it’s important for bone health and bone growth. But, a lesser-known benefit of the nutrient is that it’s important for blood clotting and may lower blood pressure, says Melissa Prest, D.C.N., R.D.N., national media spokesperson for the Academy of Nutrition and Dietetics and member of the Prevention Medical Review Board. Vitamin D is also important for bone health and regulating how much calcium is needed by the body, she adds. “Vitamin D has been reported to play a role in supporting lung function, cardiovascular health, insulin regulation and glucose metabolism, and immune health.”
Some research has found that low blood levels of vitamin D are associated with an increased risk of cardiovascular disease, says Prest. Also, calcium may reduce the risk of some cancers like colorectal cancer, she notes. Still, “the evidence exploring the relationship between dietary calcium or supplemental calcium and the risk of cancer is mixed,” Prest explains.
So, why are these results important? Oncologists prescribe a class of drugs called Aromatase Inhibitors (called anastrozole, letrozole, and exemestane) taken daily for five years to prevent breast cancer recurrence in certain women, says Madhu Shetti, M.D., oncologist and founder of Balmere. “Many women are scared to take the medicine, or they do not finish the five year course because of bone health concerns. It is critical to consider options like vitamin D/calcium supplementation so we can give everyone the best chance to protect their bone health and prevent cancer recurrence,” she explains.
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This study confirmed findings from other studies concerning reducing cancer risk and increasing cardiovascular risk from calcium and vitamin D supplements, says Prest. “However, the authors did report that their study and findings had some limitations so we cannot blanketly say that supplementation of calcium and vitamin D may not be appropriate in post-menopausal women with heart disease.” More exploration is needed to understand the association between calcium and vitamin D supplementation and cardiovascular risk, she notes.
Dr. Shetti also points out that given the study design, we are unable to distinguish the benefits of calcium and Vitamin D individually versus together. “Many individuals may take calcium or vitamin D but not both, so they may not have the same benefits as study participants,” she notes.
The bottom line
So, is a vitamin D or calcium supplement right for you? Typically, we want to reserve supplementation for people who are unable to meet their needs through food sources or those who are deficient and need the extra boost from a supplement, says Prest.
That said, every person should speak with their physician and discuss their individual risks and benefits for adding vitamin D and/or calcium supplements, suggests Dr. Shetti. Individuals at a higher risk for developing osteopenia (a loss of bone density that weakens bones but not low enough to meet the criteria for osteoporosis) or osteoporosis (a bone disease that develops when bone density and bone mass decreases) may consider supplementation after discussing with their doctor, notes Keri Gans, M.S., R.D., registered dietitian and author of The Small Change Diet. “Risk factors include white or Asian descent, smaller body frame, family history of osteoporosis, post-menopausal, and history of amenorrhea (absence of menstruation),” she explains.
Dietary supplements are products intended to supplement the diet. They are not medicines and are not intended to treat, diagnose, mitigate, prevent, or cure diseases. Be cautious about taking dietary supplements if you are pregnant or nursing. Also, be careful about giving supplements to a child, unless recommended by their healthcare provider.