A study conducted by researchers at the Indian Council of Medical Research-National Institute of Nutrition in Hyderabad has found that Vitamin D3 is more effective than Vitamin D2 in maintaining and restoring skeletal muscle and heart function, according to findings published in the journal *Molecular Nutrition and Food Research*.
The research was carried out on weaning male Sprague-Dawley rats, focusing specifically on the recovery phase from vitamin D deficiency. According to the published data, Vitamin D3 demonstrated greater improvements in muscle mass, muscle fiber size, and grip strength compared to Vitamin D2. Additionally, Vitamin D3 showed stronger effects on markers associated with muscle development, energy metabolism, cardiac contractility, and heart metabolism.
Dr. Ayesha Ismail, Scientist F at ICMR-NIN and corresponding author of the study, stated, "Vitamin D3 increased the blood levels of 25OHD, a biomarker for Vitamin D status, two-fold compared to D2 administered at the same dose. Vitamin D3 is more efficacious than D2 in certain muscle and heart related parameters."
Globally, vitamin D deficiency is classified as a pandemic affecting over 1 billion people. Between 50% and 80% of populations worldwide are considered vitamin D-insufficient or deficient. In India, nearly 80% of the population may have inadequate vitamin D levels.
Dr. Bharati Kulkarni, Director of ICMR-NIN, added, "The findings indicate that vitamin D3 may be more effective than vitamin D2 in maintaining and restoring skeletal muscle and cardiac functions." However, Dr. Kulkarni emphasized that further studies are needed to establish the effects of the two forms of vitamin D on skeletal and extra-skeletal functions, their implications for supplementation and fortification programmes, and whether these preclinical findings translate to humans.
Previous research on Vitamin D functions beyond bone health has been limited, and evidence regarding whether D2 and D3 have similar effects in these areas has remained inconclusive. A 2023 meta-analysis indicated that Vitamin D3 is approximately 87% more potent than D2 at raising and sustaining serum levels, with D3 maintaining a circulation half-life of 3 to 4 weeks compared to D2's 2 to 3 weeks.
The exact number of rats used in the study and the precise duration of the experiment were not specified in the published literature. For the general public and the supplement and food fortification industries, the results indicate potential shifts in preferred formulation choices, though direct human clinical trials remain a prerequisite for updated supplementation guidelines.
