The study included over 20,000 participants in Australia between ages 60 and 84. About half of the group took 60,000 IUs of vitamin D each month in supplement form, while the other half was given a placebo for up to five years. Researchers monitored the incidence of heart health events in the groups between 2014 and 2020. The risk of a major cardiovascular event like a heart attack at a five-year checkup was lower in the vitamin D group than in the placebo group. 

“The effect was stronger in people who were taking medications to treat cardiovascular conditions such as high blood pressure or high cholesterol,” says Rachel Neale, author on the study and deputy coordinator of the Population Health Department at the QIMR Berghofer Medical Research Institute. “People who are not vitamin D deficient should be aware that the evidence that more vitamin D is beneficial for heart health benefits is suggestive but not conclusive.”

The authors note the incidence difference was small between the two groups. 

“These findings could prompt further evaluation of the role of vitamin D supplementation, particularly in people taking drugs for prevention or treatment of cardiovascular disease,” the authors conclude. 

Vitamin D’s health benefits

Previous research has demonstrated vitamin D’s benefits for brain health. One study found that vitamin D supplementation in older adults decreased the risk of developing dementia by 40%. Higher levels of vitamin D in brain tissue has been associated with stronger cognitive function and memory. 

Sources of vitamin D and how much you need

The sun is one of the best sources of vitamin D. Foods like salmon and trout along with fortified orange juice and milk are high in vitamin D, but supplementation is also an option.

The recommended dietary allowance of vitamin D is 600 IU per day for those between age 1 and 70, and 800 IU for those over 70. 

Always check with your doctor before starting new supplements or increasing your intake. Too much vitamin D can cause calcium buildup and kidney damage.

“The current intake guidelines are designed to stop people from being vitamin D deficient if they get limited sun exposure. We aimed to see what would happen if we pushed people to a higher vitamin D level within the sufficient range” Neale says. “I would not advice a policy shift on the basis of our results. However, individual people, particularly those at risk of heart disease, may consider taking a higher dose vitamin D supplement.”