Want to Protect Your Heart? Study Suggests Don’t Skip Vitamin D

Customers browsing products at "Mr Vitamins," a chain of supplement outlets in Sydney, Australia, on Feb. 16, 2016. Saeed Khan/AFP via Getty Images

A study suggests that taking a high dose of vitamin D one time per month could cut the risk of suffering a heart attack in the long term.

Researchers in Australia randomly assigned more than 20,000 adults between the ages of 60 to 84 to take a large, 60,000-IU dose of vitamin D3 or a placebo one time per month for five years, according to a study published in the BMJ.

They found that about 6 percent of people taking the vitamin D pill and 6.6 percent of those taking the placebo had a significant cardiovascular event like a stroke or heart attack. It suggests that those who took vitamin D, which is naturally created by the skin after it’s exposed to sunlight, on a monthly basis saw 5.8 fewer events per every 1,000 people.

The rate of major cardiovascular events, such as a heart attack, was about 9 percent lower among those who took the vitamin D supplement. Specifically, the rate of heart attack was 19 percent lower in the vitamin D group.

The authors of the study noted that the absolute risk difference appears to be small. However, they said it was the largest trial of its date about the effects vitamin D has on heart health, saying that further research is now needed.

“These findings indicate that vitamin D supplementation might reduce the incidence of major cardiovascular events,” the authors of the paper wrote, adding that their “findings could prompt further evaluation of the role of vitamin D supplementation, particularly in people taking drugs for prevention or treatment of cardiovascular disease.”

Rachel Neale, a professor at the QIMR Berghofer Medical Research Institute in Queensland and who commissioned the study, said that many people don’t need to take a supplement because they’re exposed to enough sunlight on a regular basis. A vitamin D pill could be taken for individuals who do not get enough sun, she explained.

Salmon fillets at the Sydney Fish Market on December 24, 2015 in Sydney, Australia. Cameron Spencer/Getty Images

“If you want to take a supplement, I would recommend a daily dose of not more than 2,000 IU,“ Ms. Neale told WebMD. “If you’re over age 60, you should not take a vitamin D supplement solely because of the results of this study,” she added, noting that people should take ”into consideration your medical history and health status.”

Vitamin D’s “effect was stronger in people who were taking medications to treat cardiovascular conditions such as high blood pressure or high cholesterol,” Ms. Neale added. “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 body uses vitamin D to help regulate the amount of phosphate and calcium in the body, which is needed to keep muscles, teeth, and bones healthy. It also regulates blood pressure and reduces inflammation, oxidative stress, and arterial stiffness.

Other than sunlight, foods with significant vitamin D content include seafood such as tuna, salmon, oysters, shrimp, and salmon. Milk, dairy products, and tofu also have good amounts of vitamin D, health officials have said.

However, taking too much vitamin D in the form of a supplement can cause long-lasting health problems, including kidney stones and plaque buildup near blood vessels around the heart. Side-effects of too much vitamin D include muscle weakness, nausea, and vomiting.

As far as foods with vitamin D, fatty fish and seafood are good sources, particularly salmon, tuna, mackerel, oysters, and shrimp, says Dr. West. “These foods also contain high levels of omega-3 fatty acids, known to be heart-healthy.” Similarly, cow’s milk (fortified or not), yogurt and other dairy products, and tofu are all good sources of vitamin D, he adds.

The recommended dietary amount for vitamin D is about 600 IU per day for individuals aged 70 and under. For those over the age of 70, 800 IU is recommended per day.

“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” Ms. Neale cautioned, according to Fortune magazine. “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.”