Personalized vitamin D3 supplementation for heart attacks cuts risk of recurrence in half

Tailored vitamin D3 supplementation for heart attack patients may halve their risk of a second heart attack, according to new clinical findings.

Researchers at the Intermountain Health non-profit healthcare system in Salt Lake City, US, led the large, randomized trial that monitored patients’ vitamin D blood levels and optimized their vitamin D3 dosing accordingly.

Lead investigator of the study Heidi May, Ph.D., a cardiovascular epidemiologist at Intermountain Health, says the results are promising for “target to treat” dietary interventions.

“We observed no adverse outcomes when giving patients higher doses of vitamin D3 supplementation,” she adds. “We’re excited with these results but know we have further work to do to validate these findings.”

What personalized dosing does differently

The Intermountain Health researchers set out to determine if it is more important to increase a patient’s vitamin D level to a certain level rather than prescribing supplementation at a set dose. They say that previous trials prescribing standard supplementation doses did not lead to significant reduction in cardiovascular risk.

“Previous studies just gave patients supplementation without regularly checking blood levels of vitamin D to determine what supplementation achieved,” says May. “With more targeted treatment, when we checked exactly how supplementation was working and made adjustments, we found that patients had their risk of another heart attack cut in half.”

The study, called the “Target-D” trial included 630 patients who had a heart attack within one month of enrollment. Researchers watched for the occurrence of cardiovascular events for at least two years.

Among the heart attack patients enrolled in the study, 85% had insufficient vitamin D3 levels — less than 40 ng/mL in the blood.

Participants were split into two groups: those who were not prescribed vitamin D3 supplementation and those who received personalized vitamin D3 therapy.

For the vitamin D3 treatment group, researchers aimed to raise participants’ blood levels of vitamin D to more than 40 ng/mL. More than 50% in this group required an initial vitamin D3 dose of 5,000 international units (IU), where current supplementation suggestions are usually between 600 to 800 IU.

For patients in the study who received targeted treatment, their vitamin D blood levels were checked once a year to determine if they were above 40 ng/mL. Patients whose vitamin D levels were lower than that target were tested every three months while adjusting their dosage. After they reached the 40 ng/mL target, they were also tested annually. 

Clinical findings

When tracking the patients to see who had follow-up major cardiac events, the researchers assessed occurrences of heart attack, heart failure, hospitalization, stroke, or death.

Among the 630 patients enrolled in the clinical trial, 107 experienced a major cardiac event.

Researchers saw no significant difference in the risk of major cardiac events between the groups. However, they confirm that the risk of a follow-up heart attack was reduced by half in those patients who received targeted vitamin D management.

May comments that a larger study group would help researchers to adequately evaluate if targeted vitamin D management helps to reduce risks of developing other cardiovascular diseases or cardiac events.

Prevalent deficiencies

The study authors underscore that between one-half to two-thirds of people globally have low levels of vitamin D. They also flag that modern lifestyle changes based on recommendations to reduce skin cancer risk have decreased average sun exposure, which leads to this deficiency.

Their research follows earlier observational studies linking low levels of vitamin D with poor cardiovascular outcomes.

Addressing these deficiencies, the French company Nutriearth launched a vitamin D3-rich mealworm-based functional flour in Europe, which gained novel food authorization in 2023. The company recently opened its first commercial manufacturing site to produce its vitamin D3 through its patented, biomimetic technology that exposes mealworms to a specific type of light.