Vitamin D3 outperforms D2 in muscle and heart health in rat study, ICMR researchers find

Study finds vitamin D3 more effective than D2 for muscle and heart health

Researchers at the ICMR-National Institute of Nutrition (ICMR-NIN) in Hyderabad have found that vitamin D3 is more effective than vitamin D2 in maintaining and restoring skeletal muscle and heart function, based on an animal study. The findings were published in the journalMolecular Nutrition & Food Research.

The study, titled "Dietary Vitamin D2 Is Less Potent Than Vitamin D3 at Maintaining or Restoring Structure and Metabolism of Skeletal Muscle and Heart in Male Rats," compared the effects of vitamin D2, vitamin D3, and a combination of both on skeletal muscle structure and metabolism, muscle strength, and cardiac function.

While vitamin D is widely recognized for its role in calcium regulation and bone health, it also contributes to skeletal muscle and heart function. However, evidence comparing the two main forms of the vitamin—D2 and D3—in these areas has been limited.

Experimental design and findings

Researchers conducted experiments on weanling male Sprague-Dawley rats, feeding them diets containing vitamin D2, vitamin D3, a combination of both, or no vitamin D. They then evaluated body composition, muscle strength, muscle fibre structure and metabolism, along with markers associated with cardiac function.

The results showed that rats receiving vitamin D3 demonstrated greater improvements in muscle mass, muscle fibre size, and grip strength compared to those given vitamin D2. Vitamin D3 was also more effective in enhancing biological markers associated with muscle growth and energy metabolism.

Similar differences were observed in the heart, with vitamin D3 producing stronger improvements in indicators of cardiac contractility and metabolism, particularly among rats recovering from vitamin D deficiency.

Researchers' comments

Dr Ayesha Ismail, scientist F at ICMR-NIN and corresponding author of the study, said that while both forms of vitamin D improved calcium-related parameters, vitamin D2 was less effective in several measures related to muscle and heart structure and energy metabolism.

ICMR-NIN Director Dr Bharati Kulkarni said the findings suggest that vitamin D3 may be a better option for maintaining and restoring muscle and cardiac functions. However, she cautioned that further studies are required to better understand the effects of the two forms of vitamin D and their implications for supplementation and food fortification programmes.