LE Magazine September 2007
Vitamin D’s Crucial Role in Cardiovascular Protection
By William Davis, MD
Vitamin D: Essential for Heart Health
Abundant evidence now points to the numerous cardioprotective functions of vitamin D. Restoring vitamin D to normal levels has been found to help reduce inflammation, normalize blood pressure, and improve insulin sensitivity—all factors that reduce heart disease risk.15-18
Vitamin D deficiency has been shown to diminish contractile function of heart muscle cells, contribute to endothelial dysfunction, distort heart muscle structure (triggering hypertrophy, or abnormal heart muscle growth), and increase smooth muscle growth in the coronary artery wall—a process that leads to atherosclerotic plaque formation.19,20 Low levels of serum 25-hydroxyvitamin D have been linked with congestive heart failure, a condition in which the heart is unable to keep up with the body’s demands for blood and oxygen.21 A recent analysis showed that individuals with low serum levels of vitamin D had higher rates of high blood pressure, diabetes, and elevated triglycerides than those with higher vitamin D levels.22
Longstanding vitamin D deficiency is a major contributor to osteoporosis, and scientists have long known that women with osteoporosis are more likely to have coronary heart disease. The correlation between osteoporosis and heart disease may reflect common risk factors and mechanisms, such as estrogen and vitamin D.23 A study in 2,500 postmenopausal women showed a four-fold greater risk of heart attack in women with osteoporosis.24 A University of Illinois study showed that the computed tomography (CT) heart scan score (a measure of coronary atherosclerotic plaque) in women with osteoporosis averaged 222 (optimal is zero), while women with normal bone density had far lower average scores of 42.25 Similar findings have shown that higher levels of coronary calcification are found in those with lower levels of vitamin D.26,27
Vitamin D deficiency may extend to vascular disease beyond the coronary arteries. A recent Italian study determined that the greater the vitamin D deficiency, the more carotid atherosclerotic plaque was present, as assessed by carotid ultrasound. The authors concluded that low vitamin D blood levels were an independent and strong predictor of atherosclerosis. Diabetics were also twice as likely as non-diabetics to be severely vitamin D deficient.28
Some authorities have proposed that inadequate vitamin D is part of the reason for the extremely high incidence of cardiovascular disease in people with abnormal kidney function.29 People with little or no kidney function often have very low levels of vitamin D, since the kidney is required for its activation.30 A Japanese study in 240 people on dialysis for severe kidney disease suggested that treatment to correct vitamin D deficiency resulted in a dramatic reduction in heart attack and death from heart disease.31 Emerging science argues strongly in favor of vitamin D as an important risk factor for cardiovascular disease. Optimizing vitamin D status holds tremendous potential to safely, inexpensively, and dramatically reduce cardiovascular risk.
“… there is a striking similarity between the benefits of vitamin D and the benefits of statin therapy. I believe that the unexpected and unexplained beneficial effects of statin therapy might be mediated by activation of vitamin D receptors by this group of drugs.”
—Dr. David S. Grimes Blackburn Royal Infirmary, Lancashire, UK
