Cardiologists have found a simple way to reduce the risk of a second heart attack

Individualised doses of vitamin D3 help heart attack patients to reduce the risk of another heart attack by 50%. This conclusion was reached by cardiologists from Intermountain Health Medical Centre (Salt Lake City, USA), Medicalxpress reports.

The results of the large-scale clinical study were presented on 9 November at the American Heart Association scientific session in New Orleans.

Researchers followed 630 heart attack patients for six years - from April 2017 to March 2025. The study was called TARGET-D. All participants were divided into two groups: one received conventional treatment without controlling vitamin D levels, the other received personalised therapy, where vitamin D3 doses were adjusted until optimal blood levels (above 40 nanograms per millilitre) were reached.

It turned out that 85 per cent of patients initially had vitamin D levels below normal. More than half needed higher doses - about 5,000 international units (IU) per day, whereas standard recommendations are usually limited to 600-800 IU.

"We measured blood levels of vitamin D regularly and adjusted the dosage. This point-by-point approach produced noticeable results - the risk of another heart attack was cut in half," said study leader, epidemiologist Heidi May, PhD, of Intermountain Health.

No side effects or complications were reported from taking higher doses of vitamin D3. However, the researchers emphasised that this is a controlled medical use, not supplementation on its own.

Interestingly, the total number of serious cardiovascular events (heart attack, stroke, hospitalisation due to heart failure or death) did not differ between the two groups. However, recurrent heart attacks were significantly less frequent among those who received "targeted" vitamin D3 therapy.

Scientists attribute this to the fact that vitamin D affects not only the bone system, but also the state of blood vessels, inflammatory processes and metabolism. Deficiency of this vitamin is considered a risk factor for cardiovascular disease.

"We have shown for the first time that it is important not just to take supplements, but to achieve optimal levels of vitamin D in the body. This could be a new direction in the prevention of heart complications," Dr May stressed.

According to the World Health Organisation, between half and two-thirds of the world's population isvitamin D deficient. The cause is attributed to low insolation, working indoors and reduced time spent in the sun.

The next step will be to conduct a larger study to confirm the results and find out whether this approach reduces the risk of other cardiovascular diseases.