- Research suggests the use of calcium and vitamin D supplements may reduce the risk of cancer deaths in postmenopausal women but may also increase the risk of death from cardiovascular disease.
- Calcium and vitamin D supplements are often recommended for postmenopausal women to prevent bone loss.
- Experts say the research should be interpreted with caution and women should discuss with their doctor whether they should take supplements.
Use of calcium and vitamin D supplements in women who are postmenopausal may reduce the risk of death from cancer, but they may also increase risk of death from cardiovascular disease.
That’s according to research published today in the journal Annals of Internal Medicine, which reports that women who took calcium and vitamin D supplements had a 7% lower risk of death from cancer but a 6% higher risk of death from cardiovascular disease.
“Our study also found an 11% lower risk for total cancer, including 31% and 19% lower incidences of colorectal cancer and invasive breast cancer,” the study authors wrote.
To reach their findings, the researchers from the University of Arizona conducted a follow-up analysis to the largest ever randomized trial of calcium and vitamin D supplementation, which examined the health outcomes of those supplements on more than 36,000 postmenopausal women.
However, the study authors note that due to the way the study was undertaken, the results should be interpreted carefully.
“Given the study design, we could not disentangle the added benefit or harms of supplementation with calcium and vitamin D in combination versus vitamin D alone, a topic worthy of future study,” they wrote.
Dr. Howard Hodis, an internal medicine specialist with Keck Medicine of USC in California who was not involved in the study, said there could be a number of factors that might explain a reduction in cancer risk among the group studied.
“It’s important to understand that this is a follow-up that’s done after the trial ended. So it’s really an observational follow-up of individuals who were in a previous trial and so they’re no longer under randomized conditions,” he explained to Medical News Today.
“There’s a lot of factors that can bleed into that. It could be that with the reduction of cancer, maybe that’s a more healthy group in some way. They exercise more, they’re thinner, they’re eating better, there’s no way to know whether that’s true or not,” Holis added.
Previous observational studies have indicated that those who take calcium supplements have a greater risk of cardiovascular disease-related events than those who don’t take calcium supplements. Low levels of estrogen seen in menopause can also raise the risk of heart disease and stroke.
The risk of cardiovascular disease events is particularly significant for those who consume more than 1,400mg of calcium a day.
For women aged over 50, the recommended daily intake of calcium is 1,200mg a day.
During menopause, a decrease in the production of estrogen reduces the absorption of calcium and increases urinary calcium loss.
After menopause, women lose roughly 1% of their bone mineral density each year. As a result, 30% of postmenopausal women in the United States have osteoporosis and of these at least 40% will experience at least one fracture that occurs due to a minor trauma such as a fall.
“Every woman during this menopause transition and beyond is at risk for osteopenia and osteoporosis. And osteoarthritis fractures will be deadly later in life. So that’s the reason why we are very, very focused in women’s health on protecting women’s bones as they go through the midlife transition and beyond,” Dr. Leah Millheiser, a clinical professor of obstetrics and gynecology at Stanford University in California who was not involved in the study, told Medical News Today.
“So it is important to get enough calcium and vitamin D, but you have to weigh that… We have to look at every woman as an individual. What are her risk factors? Does she have a medical condition where we don’t want her to get extra calcium? Is she somebody who has a high calcium score?… They are all things that we need to take into consideration,” Millheiser added.
Dr. G Thomas Ruiz, a lead OB/GYN at MemorialCare Orange Coast Medical Center in California who wasn’t involved in the study, says hormone replacement therapy can also be useful for protecting the bone health of postmenopausal women.
“In my ideal world, you’d have women on hormone replacement therapy, taking vitamin D and calcium supplementation to really minimize the risk of osteoporosis. However, women with breast cancer don’t have the option of hormone replacement therapy,” Ruiz told Medical News Today.
“The thought is with weight bearing exercise, and supplementing with calcium and vitamin D, that you will slow down the loss of calcium from the bone. And that seems to be true. It’s not perfect, but it’s better than nothing,” he added.
The link between vitamin D and reduced cancer mortality
The Arizona research builds on previous research that indicates a potential connection between vitamin D levels and reduced risk of cancer.
Past research has found a 17% lower cancer mortality among men and women with prostate, lung, colorectal, and ovarian cancers and higher concentrations of vitamin D.
“Our findings that effects on cancer end points seem more prominent among those without prior calcium and vitamin D supplementation suggest that calcium and vitamin D supplementation may affect cancer biology primarily in the setting of augmenting an insufficiency in nutrient status,” the authors of the new study wrote.
Experts say the best thing women can do to stay healthy during and after menopause is to be active, quit smoking, have a healthy diet, and discuss whether supplements are appropriate with a healthcare provider.
“This isn’t a one size fits all conversation. You have to look at every woman and her medical history,” Millheiser said.
By Elizabeth Pratt on March 12, 2024 — Fact checked by Jennifer Chesak, MSJ (MedicalNewsToday)
