Cardiovascular disease (CVD) is the leading cause of death among adults over 65. At the same time, many older adults have low levels of vitamin D, and past studies have linked low vitamin D levels to a higher risk of heart disease. This connection led many people to believe that taking vitamin D supplements might help protect the heart.
However, new research from Beth Israel Deaconess Medical Center (BIDMC) challenges this idea. In a well-designed study, scientists found that even high doses of vitamin D did not lower the risk of heart disease in seniors with low vitamin D levels.
The study was published in the American Journal of Preventive Cardiology and led by Dr. Katharine W. Rainer, a resident physician at BIDMC.
She explained that although earlier research showed a connection between low vitamin D and higher heart disease risk, this new trial clearly shows that vitamin D supplements don’t actually reduce signs of heart strain or damage—even when taken in high doses over a two-year period.
The research team used data from a large trial called the STURDY study (Study to Understand Fall Reduction and Vitamin D in You), which was originally created to see if vitamin D supplements could help prevent falls in older adults.
Sponsored by the National Institute on Aging, the trial ran from 2015 to 2019 and included adults aged 70 and older who had low vitamin D levels.
Participants were randomly assigned to one of four groups. Each group received a different daily dose of vitamin D3: 200, 1000, 2000, or 4000 international units (IU). The study was “double-blind,” which means neither the participants nor the researchers knew who was receiving which dose during the trial. This helps ensure that the results are accurate and not biased.
To understand how vitamin D might affect heart health, the researchers measured levels of two specific proteins in the blood that are linked to heart strain and damage. They took blood samples at the beginning of the study and then again at several points during the two years that followed.
While people with lower vitamin D levels did have higher levels of one of these heart-related proteins at the start of the study, taking vitamin D supplements—at any dose—did not lead to lower levels of these proteins over time.
The results were consistent, no matter the participants’ age, sex, race, or whether they had other health problems like high blood pressure or diabetes.
Dr. Stephen P. Juraschek, senior author of the study and research director at the BIDMC Hypertension Center, explained that although low vitamin D and heart disease are connected, that doesn’t mean one causes the other.
He suggested that other factors—such as how physically active a person is, especially outdoors where they also get sunlight (a natural source of vitamin D)—could play a bigger role in protecting heart health.
In short, while having low vitamin D levels is linked to a higher risk of heart disease, this new study shows that simply taking vitamin D supplements doesn’t lower that risk. This finding adds to a growing body of evidence that questions the benefit of vitamin D supplements for heart health.
The researchers say it’s important to look at other possible ways to protect the heart, such as increasing physical activity, eating a healthy diet, and managing conditions like high blood pressure and diabetes.
If you’re concerned about heart health, some studies have shown that simple dietary choices, like drinking apple juice or eating yogurt, may offer some benefits. Other research has suggested that nutrients like zinc and vitamin B6 could also play a role in lowering the risk of heart disease. However, more research is needed to fully understand how all these factors work together.
For now, this study sends a clear message: taking high doses of vitamin D might not protect your heart. Instead, a healthy lifestyle that includes regular movement, good nutrition, and proper medical care remains the best way to support long-term heart health.
If you care about heart disease, please read studies about a big cause of heart failure, and common blood test could advance heart failure treatment.
For more information about heart health, please see recent studies about a new way to repair human heart, and results showing drinking coffee may help reduce heart failure risk.
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