- A new study looks at how common supplements are associated with mortality risk from heart disease and cancer.
- The study found that women taking calcium and vitamin D had a lower risk of dying from cancer.
- But women had a slightly increased risk of dying from heart disease if they were postmenopausal.
Calcium and vitamin D supplements appear to lower the risk of dying from cancer, and, potentially, slightly increase the risk of dying from heart disease in postmenopausal women, new research suggests.
The Women’s Health Initiative (WHI) previously investigated the health effects of daily calcium and vitamin D supplementation in postmenopausal women but didn’t notice any significant effects.
The recent report, published this month in the Annals of Internal Medicine, looked at follow-up death data on those participants to identify the longer-term health effects associated with calcium and vitamin D (CaD) supplementation.
In the United States, older women’s diets tend to lack vitamin D and calcium, past evidence suggests, causing many doctors to recommend supplementation to those in this age group.
“This study highlights the complex relationship between supplements and biological effects and clinical outcomes, and the need for more research in this field,” Dr. Cheng-Han Chen, board-certified interventional cardiologist and medical director of the Structural Heart Program at MemorialCare Saddleback Medical Center in Laguna Hills, CA, told Healthline.
Chen was not involved in the study.
Calcium and vitamin D supplements appear to lower the risk of cancer mortality
The researchers evaluated health data gathered from the WIH’s trial in addition to National Death Index data to determine if long-term daily calcium and vitamin D supplements impacted women’s risk of cancer or heart disease.
The researchers specifically looked at whether the women, who originally participated in the WIH trial, developed cancer, heart disease, had a hip fracture, or died in the years that followed the trial.
They found that the women who took calcium and vitamin D supplements had a 7% lower risk of dying from cancer over the course of 22 years compared to those who took a placebo.
They also discovered that those who took the supplements faced a 6% higher risk of dying from cardiovascular disease. The cardiovascular effects were most pronounced in women who’d been taking supplements before they were assigned to take supplements as part of the trial.
Supplementation appeared to have no notable impact on the overall prevalence of cancer, heart disease, hip fractures, or all-cause mortality.
“This study found a long-term association between calcium and vitamin D supplementation in postmenopausal women and decreased cancer mortality and increased cardiovascular disease mortality, without a difference in all-cause mortality,” Chen explained.
Why calcium and vitamin D can influence your health outcomes
While it’s unclear why, exactly, calcium and vitamin D supplements may impact the development of cancer, some research suggests they decrease tumor invasiveness, impede angiogenesis (or blood vessel formation) in and around tumors, and affect gut functions and bile acid production.
Past evidence also suggests vitamin D, specifically, increases tumor gene suppression and regulates inflammation in the body.
It may also decrease cancer cell growth and increase cell death, says Fredrick Schumacher, PhD, MPH, Associate Professor in the Department of Population and Quantitative Health Science at Case Western Reserve University’s School of Medicine.
Schumacher was not involved in the study.
A recent meta-analysis, which looked at the findings from five trials, determined that vitamin D supplementation was linked to 13% reduction in cancer mortality.
Though evidence on calcium and vitamin D supplementation and heart disease has been mixed, some researchers suspect extra calcium may lead to calcification of coronary arteries, thereby increasing the risk of dying from heart disease.
Past research has also identified a link between calcium supplementation and a higher risk of coronary heart disease, regardless of whether people also took vitamin D supplements.
“Coronary artery calcification is when the arteries become hardened and narrowed overtime due to calcium deposits and plaque buildup. This can increase the risk of heart disease, heart attacks, and strokes,” Michelle Routhenstein, MS, RDN, CDECS, CDN, a preventive cardiology dietitian at Entirely Nourished, said.
Routhenstein was not involved in the study.
Should you take calcium or vitamin D supplements?
According to Chen, calcium and vitamin D supplementation is routinely recommended for people who don’t get enough calcium in their diet along with postmenopausal women.
The supplements are primarily used to prevent osteoporosis and fractures in older adults, however, their use has been controversial.
Doctors often disagree on the optimal doses and regiments of calcium and vitamin D supplementation and some physicians have voiced their concerns about not knowing the long-term health effects, according to past research.
Routhenstein says calcium supplementation should be used in people who have low calcium levels.
Not getting enough calcium increases the risk of osteoporosis, which is a risk factor for heart disease, she added.
That said, it’s crucial to be prudent and intentional when taking any supplements.
For example, the absorption is highest with supplements that are 500mg or less.
“When calcium supplements are used without assessing current calcium intake, the excess may contribute to coronary artery calcium progression,” says Routhenstein.
More research is needed to determine the ideal duration and dosage, Schumacher says.
“The authors report several important observations related to nutrition and long-term health among post-menopausal women, however, these results need to be replicated. Furthermore, the generalizability of these findings need to be evaluated in additional groups, especially more diverse populations,” Schumacher said.
The bottom line:
Calcium and vitamin D supplements appear to lower the risk of dying from cancer, and, potentially, slightly increase the risk of dying from heart disease in postmenopausal women, new research suggests. In the United States, older women’s diets tend to lack vitamin D and calcium, causing many doctors to recommend supplementation in this age group. The new study underscores how future research is needed to better understand the long-term health effects linked to daily supplement use.
