Vitamin D is a fat-soluble vitamin that your body produces from cholesterol, with the help of the sun. Vitamin D is necessary for calcium absorption; however, its functions in the body are far more numerous than once thought. Among its effects, research has uncovered a variety of benefits of vitamin D for the cardiovascular system.
Blood Pressure
Vitamin D deficiency may contribute to high blood pressure, according to a study published in the February 2011 "Journal of Investigative Medicine." Its role as a hormone that inhibits the renin-angiotensin system in the kidney -- a system of hormones that increases blood pressure by promoting water retention by the kidneys -- makes it a key nutrient in blood pressure management and a potentially powerful target for therapy to prevent and reduce elevated blood pressure in some people.
Inflammation
Vitamin D exerts effects on several organ systems, including the cardiovascular system, according to a report published in the February 2001 issue of "Current Hypertension Reports." Vitamin D acts as a steroid hormone to reduce blood pressure, decrease inflammation, improve insulin sensitivity and reduce complications and death rates from cardiovascular disease. Vitamin D exists in several different forms and more studies are needed to determine the relative effectiveness of the various natural and synthetic forms of the vitamin on aspects of cardiovascular health.
Cholesterol
An eight week study, published in the January 2011 issue of the "International Journal of Food Science and Nutrition," found vitamin D ineffective at lowering cholesterol in overweight patients. Study participants took 1,200 IU per day of vitamin D along with a multivitamin and mineral supplement; no significant changes were observed in cardiovascular disease risk markers and in particular, levels of HDL cholesterol were unaffected. The researchers noted that supplementation did not increase blood levels of vitamin D to desirable levels in most participants.
Stroke Prevention
High dose vitamin D supplementation improved arterial function in stroke patients, in a study published in the December 2010 issue of "Nutrition, Metabolism and Cardiovascular Diseases." In the study, stroke patients with blood levels of vitamin D below 75 nmol/L took 100,000 units of vitamin D2 for 16 weeks. Systolic blood pressure -- the top number of the blood pressure ratio -- did not change in response to vitamin D supplementation; however, arterial dilation related to improvements in the endothelium -- the inner lining of the arteries -- was significantly higher in the vitamin D group at eight weeks, although the benefit was not observed at 16 weeks. The researchers concluded that vitamin D produced a short-term improvement in endothelial function.
References
- "Journal of Investigative Medicine"; Molecular Mechanism of Vitamin D in the Cardiovascular System. Li YC; 2011
- "Current Hypertension Reports"; Vitamin D Therapy and Cardiovascular Health. Judd SE, et al; 2011
- "International Journal of Food Science and Nutrition"; Effects of vitamin D supplementation on 25-hydroxyvitamin D, high-density lipoprotein cholesterol, and other cardiovascular disease risk markers in subjects with elevated waist circumference. Maki KC, ;et al; 2011
- "Nutrition, Metabolism and Cardiovascular Diseases"; The effect of vitamin D replacement on markers of vascular health in stroke patients - A randomised controlled trial. Witham MD, et al; 2010
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