Heart disease is the leading cause of death in the US, responsible for roughly 1 in 5 deaths every year.
But researchers think there may be a promising and simple way to slightly reduce your risk of heart problems: Taking vitamin D supplements.
In a large Australian study that spanned six years and involved over 21,000 people, researchers found that older adults who took vitamin D supplements had a mildly lower risk of cardiovascular events, particularly heart attacks.
The study looked at participants between the ages of 60 and 84, and took lifestyle factors, such as diet, as well as current cardiovascular medication, into account. They were randomly selected to either take one monthly vitamin D3 supplement (60,000 IU) or a placebo.
Heart attack risks went down by a fifth
The study's researchers believed vitamin D could improve heart health by reducing inflammation, regulating blood pressure, and preventing vascular smooth muscle dysfunction.
The biggest findings were that the rate of major cardiovascular events was 9% lower in the group that took the supplements, with the rate of heart attacks 19% lower in that group. There was no difference in the rate of stroke between the two groups.
The findings are promising, but take them with a grain of salt
Professor Rachel Neale, one of the lead researchers of the study, told Insider that, "while the findings are suggestive of benefit, they're not conclusive."
First, the supplements were slightly more effective in people already taking statins. Studying people who aren't taking cardiovascular drugs may help to show the true effect of vitamin D3 supplements.
Also, the study used monthly supplements, because people are more likely to stick to a monthly pill than a daily one. But Neale said "there have now been some publications suggesting that daily dosing has more effect than monthly dosing."
The study also used older participants, so it's unclear how vitamin D3 would help people under the age of 60.
In the end, the researchers concluded that "vitamin D supplementation might reduce the incidence of major cardiovascular events," but stressed that more research is warranted.
At the same time, Neale believes it's unlikely a study of this size will be repeated any time soon. "To be honest, I don't think we're going to get more conclusive evidence because nobody else is going to do the same type of trial," she said. "It's very expensive."
Vitamin D supplements aren't cure-alls
Neale said there are no "simple takeaways" from this study. While she doesn't think taking vitamin D supplements will harm anyone, she "would argue that we've got better evidence for healthy food than we have for vitamin D supplementation when it comes to reducing heart attacks."
Vitamin D is linked to many other health benefits as well, such as improving bone health, strengthening the immune system, and possibly reducing the risk of cancer or depression — though more research is still needed in these areas.
