ICMR-NIN study shows vitamin D3 outperforms D2 in muscle and heart support

Researchers from ICMR-National Institute of Nutrition (ICMR-NIN) have demonstrated the importance of vitamin D3 over vitamin D2. Image is for representational purposes only.

ICMR-National Institute of Nutrition (ICMR-NIN), Hyderabad, researchers found vitamin D3 to be more effective than vitamin D2 in maintaining and restoring muscle and heart function, at least in animal studies in their latest study.

What does vitamin D do to the body?

Vitamin D is widely known for its role in maintaining bone health and regulating calcium levels. However, it also plays an important role in the functioning of skeletal muscles and the heart. The nutrient is mainly available in two forms: vitamin D2 and vitamin D3, which are commonly used in supplements and food fortification programs.

The researchers conducted experiments on weaned male Sprague-Dawley rats to compare them. The animals were fed a diet containing vitamin D2, vitamin D3, a combination of both, or a diet deficient in vitamin D. The team then assessed body composition, muscle strength, muscle structure, energy metabolism and markers associated with heart function.

They found that rats given vitamin D3 showed greater improvements in muscle mass, muscle fiber size, and grip strength than rats given vitamin D2. Vitamin D3 was also more effective in boosting biological markers associated with muscle growth and energy metabolism.

Similar benefits were also found for heart health, as vitamin D3 had stronger effects on indicators of cardiac contractility and metabolism, particularly in rats recovering from vitamin D deficiency. Researcher Ayesha Ismail, also a corresponding author of the study, said that while both forms of vitamin D improved calcium-related parameters, vitamin D2 was less effective on several measures of muscle and heart structure and energy metabolism.

ICMR-NIN director Bharati Kulkarni said the findings suggest vitamin D3 may be a better choice for maintaining and restoring muscle and heart function. However, she cautioned that more studies are needed to better understand the effects of these two forms of vitamin D and their implications for supplementation and food fortification programs, according to the news release.

Published – 02 Sep 2026 15:04 IST