Research Summary

Individuals in the United States Are Not Achieving Optimal Vitamin D Levels

Jessica Ganga

Researchers found that current vitamin D dosing recommendations are not helping individuals achieve optimal vitamin D levels, thus putting them at risk of experiencing a cardiac event, according to a randomized trial.1

According to the study, low vitamin D levels are associated with increased risk of cardiovascular events, such as heart attack or stroke. Further, the prevalence of vitamin D deficiency—defined as less than or equal to 20 ng/mL—in the United States is estimated at 40%. Currently, the recommended dietary allowance of vitamin D in the US is 600 to 800 IU.

Using the randomized event-driven trial, Target-D, the researchers sought to provide an overview of dosing and titration for individuals to achieve vitamin D serum levels greater than 40 ng/mL.

A total of 632 participants were included in the trial, and 316 participants were used for analysis. Of the 316 individuals, 89.4% (n = 279) required vitamin D3 dosing. Only 13.5% of participants were able to achieve a vitamin D serum level of greater than 40 ng/mL using less than 2000 IU. Further, the researchers found that participants randomized to vitamin D3 doses well above the recommended dose in the US. The researchers found that 20.8% needed 3000 to 4000 IU, 51% needed 5000 to 8000 IU, and 14.6% required greater than 10,000 IU.

“We’ve seen a series of studies that report an association between low vitamin D and poor heart outcomes, but also a few randomized clinical trials that do not report the same association,” lead author Heidi May, PhD, an epidemiologist at Intermountain Health, said in a press release.2 “Our findings here show that just giving patients some vitamin D does not help them achieve optimal levels. If researchers are going to further look at vitamin D dosing as a possible way to improve heart health, patients need to be given the right doses to reach those ideal levels.”



  1. Le VT, Babcock D, Wayman L, et al. Abstract 14841: higher than daily RDA recommended vitamin D3 dosing and multiple titrations are required to achieve >40 ng/mL 25-hydroxy vitamin D levels in acute coronary syndrome (ACS) participants enrolled and randomized to targeted vitamin D treatment: the target D trial. Circulation. Published online November 6, 2023. doi:10.1161/circ.148.suppl_1.14841
  2. New study finds current dosing recommendations may not help patients achieve optimal vitamin levels. News release. Intermountain Health; November 12, 2023. Accessed February 28, 2024.