There is now overwhelming evidence that vitamin D3 is essential for your heart and cardiovascular system. In a study published in January, 2018, in the International Journal of Nanomedicine, the outcome suggests that vitamin D plays a vital role in protecting and restoring the damage to your endothelium (the thin layer of tissue that lines the blood vessels within your vascular system) done by serious health conditions such as atherosclerosis, diabetes, high blood pressure, insulin resistance and tumor growth. The study also suggests that the addition of vitamin D in the diet also triggers nitric oxide, a molecule which plays an important role in controlling blood flow and preventing blood clot formation in your blood vessels. Vitamin D3 was also shown to significantly reduce oxidative stress in your vascular system, resulting in prevention of development and/or progression of CVD. Low vitamin D has been shown to contribute to arterial stiffness and impaired blood vessel relaxation.