Making Healthy Choices™

Vitamin D and Risk of Heart Disease

Research continues to accumulate on the benefits of vitamin D to your health. The latest evidence found is the role vitamin D plays in heart health, and it comes from the famous Framingham Heart Study. Researchers studied 1,739 offspring from the Framingham study. At the start of the study, vitamin D blood levels (25 OH vitamin D) were measured to see who might be deficient. Five and a half years later, researchers recorded who had heart attacks, strokes, and coronary artery disease. Here is what they found:

• When researchers divided people into two groups, based on their blood vitamin D levels, those with low vitamin D levels (less than 15 ng/mL) had twice as many (RR=2.04) cardiovascular events (i.e., heart attacks, angina, and stroke) than those with higher levels of vitamin D after adjusting for age and sex.
• When researchers adjusted for additional coronary risks, such as high blood pressure, diabetes, blood lipids, smoking, and BMI, the increased coronary risk for low vitamin D levels still remained high, at a 62% increased risk. This implies that low vitamin D levels are an independent risk factor from other risks.
• People with high blood pressure and low vitamin D levels had the highest coronary risk. They were 2.42 times more likely to develop a serious cardiovascular problem than those getting adequate vitamin D.
• The increased coronary risk with low vitamin D levels was found to be stepwise related; the lower the vitamin D level, the higher the coronary risk. If people with high blood pressure had low vitamin D levels (less than 15 ng/mL), their coronary risk increase by 93% higher. If vitamin D levels were even lower (less than 10 ng/dL), coronary risk increased by 2.51 times compared to people with adequate vitamin D levels.

How many people were low in vitamin D? In this study from the Boston area, 28% of the people were found to be low (blood vitamin D levels less than 15 ng/mL). That means that 1 in 4 people are deficient in vitamin D to the point that it could increase their risk of a heart attack by 2-2.5 times that of persons with normal levels (15+ ng/dL). Fortunately, there is an easy an inexpensive way to correct this problem.

Bottom line. If you live in the northern half of North America, you have a high probability of being deficient in Vitamin D, especially if you don’t get out in the sunshine frequently. If you are concerned, ask your doctor to check your blood vitamin D levels. The preferred blood test is a measure of 25-hydroxy-vitamin D (25-OH D). If your level runs less than 15 ng/mL, you are at increased risk. The recommended therapy to correct this problem (or prevent it) is to get frequent exposure to sunshine. Ten to 15 minutes two or more times daily is generally adequate. However, those living in the Northern U.S. can’t make adequate vitamin D from sunshine in the winter due to the low angle of the sun. In this case you need to be sure to get adequate vitamin D from your diet. To correct vitamin D deficiency, the authors of this study recommended dietary amounts of at least 800 IU/day or more (1,000 IU/day is a frequently recommended intake for correcting deficiencies).