Vitamin D plays a critical role in multiple systems in the human body, from its function in calcium and phosphorus metabolism to modulating the immune system and reducing the risk of cardiovascular disease ( Grober et al. 2013). Unfortunately, factors such as diet, geographic location, and skin pigmentation are contributing to an increased prevalence of vitamin D deficiency worldwide, consequently leading to a higher rate of associated diseases. Namely, it has been shown that cardiovascular diseases such as coronary artery disease (CAD), hypertensive vascular disease and myocardial infarction are more common in people with lower levels of vitamin D in their body (Lavie, Lee & Milani 2011). often be obtained by two different methods. The main method is the conversion of 7-dehydrocholesterol in the skin to vitamin D3 through exposure to the sun to absorb ultraviolet B radiation with a wavelength of 290–315 nm (Holick 2007). The other method is through consumption in diets through plants in the form of vitamin D2; or fatty fish, supplements or products enriched with vitamin D in the form of vitamin D3 (Lavie, Lee & Milani 2011). Vitamin D undergoes hydroxylation twice; first with the enzyme 25-hydroxylase to form 25-hydroxyvitamin D (Calcidiol) (Al Mheid et al. 2013). Then, calcidiol is converted into the more active form of vitamin D, the hormone 1,25-dihydroxyvitamin D (calcitriol) with the help of renal 1--hydroxylase in the kidney (Al Mheid et al. 2013). Vitamins D2 and D3 are relatively similar as they share the same hydroxylation pathway to produce calcidiol (Tripkovic 2013), however, D3 has been shown to have a greater influence on calcidiol levels and therefore more effective in maintaining vitamin health D (Heaney et al. 2011). .C...... at the center of the article......, RL & Armas, LAG 2011, "Vitamin D3 is more potent than vitamin D2 in humans", The Journal of Clinical Endocrinology & Metabolism, vol. 96, no. 3, pp. E447-E52.Holick, MF 2007, 'Vitamin D deficiency', New England Journal of Medicine, vol. 357, n. 3, pp. 266-81.Lavie, CJ, Lee, JH & Milani, RV 2011, 'Will vitamin D and cardiovascular disease live up to expectations?', Journal of the American College of Cardiology, vol. 58, no. 15, pp. 1547-56.Reid, IR & Bolland, MJ 2012, 'Role of vitamin D deficiency in cardiovascular disease', Heart, vol. 98, no. 8, pp. 609-14.Tripkovic, L 2013, 'Vitamin D2 vs. vitamin D3: are they the same thing?', Nutrition Bulletin, vol. 38, no. 2, pp. 243-8. Zittermann, A 2006, 'Vitamin D and disease prevention with particular reference to cardiovascular disease', Progress in Biophysics and Molecular Biology, vol. 92, no. 1, pages. 39-48.