Ongoing research conducted by Intermountain Health is investigating the potential health benefits of vitamin D, particularly in relation to reducing the risk of heart problems. The first phase of a clinical trial has been completed, and the findings suggest that the current recommended dietary allowances for vitamin D may not be sufficient to achieve optimal serum levels. The next phase of the trial aims to determine if higher vitamin D levels are associated with a decreased risk of adverse cardiovascular events such as heart attack and stroke. However, current evidence does not strongly support the claim that taking vitamin D supplements can reduce the risk of cardiovascular disease, according to the National Institutes of Health (NIH).
Various proposed mechanisms suggest how vitamin D may contribute to cardiovascular health, including promoting glucose metabolism and insulin sensitivity, enhancing endothelial function in blood vessels, regulating blood pressure and volume, and inhibiting inflammation. However, studies investigating the effects of vitamin D supplementation have not consistently demonstrated a clear benefit in preventing cardiovascular events.
Observational studies have shown an association between low vitamin D levels and an increased risk of cardiovascular events, such as heart attacks or strokes. The reasons behind this association are not fully understood, but it is hypothesized that vitamin D receptors in cells throughout the vascular system may be involved in promoting blood vessel inflammation, which in turn could contribute to heart disease.
The recommended dietary allowance for vitamin D is currently 600 international units (IU) for adults under 70 years of age and 800 IU for adults over 70. However, the researchers conducting the clinical trial suggest that these doses may not be adequate for achieving therapeutic levels of vitamin D. In fact, their findings indicate that higher doses of vitamin D supplementation are needed to reach optimal serum levels. Moreover, it took time for participants in the study to reach the target vitamin D level, with less than 65% achieving it at three months and 25% requiring six months of intervention.
The clinical trial, known as TARGET-D, has recruited 632 participants who have experienced acute coronary syndrome. The participants were divided into a vitamin D intervention group and a standard care group. The initial analysis of the trial’s data revealed that higher doses of vitamin D were necessary to achieve therapeutic levels in this group. The next phase of the research will determine if achieving vitamin D levels greater than 40 ng/mL in this group can lead to improved cardiovascular disease outcomes. However, the study has limitations, including the small number of participants and the discontinuation of vitamin D intervention by some participants, which may have influenced the results.
If the TARGET-D trial demonstrates that achieving vitamin D levels above 40 ng/mL reduces the risk of adverse cardiovascular events, clinicians may need to be more proactive in testing and treating low vitamin D levels. The completion of this trial is crucial in providing more insight into the potential benefits of vitamin D supplementation in reducing cardiovascular risks. The researchers aim to complete data collection for the study by May 2024.