This supplement could dramatically cut heart attack risk, scientists say

Researchers call for rigorous monitoring protocol to adjust vitamin D supplementation every three months

Scientists have found tailoring the intake of vitamin D in patients diagnosed with heart disease can dramatically cut the risk of heart attacks.

The finding suggests individualising vitamin D doses for patients based on their blood levels rather than administering uniform “one-size-fits-all” doses as has been done commonly until now.

Vitamin D is a hormone mainly synthesised in the skin via sunlight exposure, and is known for its positive effects on inflammation and heart health.

Widespread vitamin D insufficiency and the growing burden of heart disease globally emphasise the need for simple, cost-effective interventions to reduce death risk.

While low vitamin D concentration is linked to adverse heart disease outcomes, intervention studies until now have yielded inconsistent results, researchers say.

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Now, scientists call for tailoring vitamin D intake for each patient to achieve optimal circulating levels as a key strategy to mitigate heart disease risk.

“Our results suggest that targeting vitamin D supplementation based on blood levels can significantly diminish the risk of subsequent heart attacks,” said epidemiologist Heidi T May from Intermountain Health.

“This approach demands a personalised, vigilant clinical protocol that diverges from the traditional fixed-dose model,” said Dr May, an author of the study presented at the American Heart Association’s Scientific Sessions 2025.

Researchers recommend a rigorous monitoring protocol which adjusts vitamin D supplementation every three months.

The latest clinical trial assessed 630 adult participants diagnosed with acute heart disease at Intermountain Medical Center in Utah for a six-year period, with an average follow-up of just over four years.

Nearly half had a history of prior heart attack.

Over 85 per cent of participants initially had suboptimal vitamin D levels below 40 nanograms per millilitre (ng/mL) of blood, underscoring widespread insufficiency of the hormone in this population.

Researchers grouped the participants randomly into two groups – one, which received standard care without vitamin D level management, and another treatment arm, which underwent serial blood testing and personalised dosing of the hormone to surpass the 40 ng/mL threshold safely.

Scientists found that the treatment group experienced a 52 per cent reduction in the risk of recurrent heart attacks compared to controls.

This finding marks one of the most significant effect sizes reported in recent vitamin D cardiovascular research, researchers noted.

However, researchers urge doctors to be cautious of the findings as it remains to be corroborated by larger, peer-reviewed trials.

Nonetheless, they say the data could pave the way for new heart attack prevention strategies centered on nutrient optimisation.