A lot of evidence is suggesting that a large part of the population have suboptimal levels of vitamin D.
The research referenced here reviewed the evidence that vitamin D deficiency is associated with cardiovascular disease and also the evidence that supplementation of vitamin D is associated with reduction in cardiovascular disease (Lavie CJ, et al. 2011).
Vitamin D is not only important for the cardiovascular system, but affects a lot of functions. Low levels of vitamin D can adversely affect the parathyroid hormone, increase insulin resistance and lead to high blood pressure, left ventricular enlargement of the heart, metabolic syndrome, diabetes, increased systemic inflammation and increased risk of atherosclerosis.
When supplementing with vitamin D, use vitamin D3 which is the most beneficial form. Most people can benefit supplementing with 1000 IU to 2000 IU of vitamin D3. If your vitamin D levels are very low you can use a higher amount for a limited time to bring the values up quicker. Testing for 25-hydroxy vitamin D is the best way to determine your level. Read more about vitamin D by clicking here.
Lavie CJ, Lee JH, Milani RV. Vitamin D and cardiovascular disease will it live up to its hype? J Am Coll Cardiol. 2011 Oct 4;58(15):1547-56.