Low Vitamin D Increases Risk of Heart Disease, Stroke
Low levels of vitamin D may significantly increase a person’s risk of heart disease, stroke, and death, even among people who have no history of heart disease, according to researchers at the Heart Institute at Intermountain Medical Center in Salt Lake City. The findings were presented at the American Heart Association’s Scientific Conference in Orlando, Florida, on November 16.
Recent studies have highlighted the importance of maintaining adequate levels of vitamin D, including the ability of the sunshine vitamin to improve insulin resistance, protect against high blood pressure, safeguard older adults against the risk of heart disease, reduce the risk of preeclampsia, and help in bone health, among other benefits. Vitamin D has even been suggested to help protect against H1N1, or swine flu.
Most Americans have low levels of vitamin D, placing them at risk for a range of serious health problems. According to the Vitamin D Council, everyone should maintain a vitamin D level of greater than 50 nanograms per milliliter (ng/mL). Research shows that the body does not begin adequately storing the vitamin until the nutrient reaches that level. Below 50 ng/mL the body uses up vitamin D as fast as the body can make it or take it in. Because 30 ng/mL is considered “normal” in conventional medical circles, by these standards most Americans are deficient.
In the Intermountain Medical Center study, researchers followed 27,686 patients ages 50 and older who had no prior history of cardiovascular disease. Vitamin D levels were measured in all the participants and the individuals were divided into three groups based on the results: normal vitamin D levels (greater than 30 ng/mL), low (15-30 ng/mL), and very low (less than 15 ng/mL).
The researchers found that participants who had very low levels of vitamin D were 77 percent more likely to die, 45 percent more likely to develop coronary artery disease, and 78 percent more likely to have a stroke than individuals who had normal levels. Compared with participants who had normal vitamin D levels, those with very low levels were also twice as likely to develop heart failure.
In the news release issued by the Heart Institute, Brent Muhlestin, MD, director of cardiovascular research of the Heart Institute at Intermountain Medical Center, and one of the study’s authors, noted that these findings show “how we can prevent disease and provide treatment [that] may ultimately help us save more lives.” He said that “this was a unique study because the association between Vitamin D deficiency and cardiovascular disease has not been well-established.”
Another member of the research team, epidemiologist Heidi May, PhD, MS, emphasized that their findings were important because it showed that even a moderately low deficiency of the sunshine vitamin was associated with cardiovascular events. “This is important because Vitamin D deficiency is easily treated. If increasing levels of Vitamin D can decrease some risk associated with these cardiovascular diseases, it could have a significant public health impact.”
Dr. Muhlestein noted that because the study was observational, it did not establish a definitive association between heart disease and vitamin D deficiency. However, the results were significant enough to warrant further treatment trials to verify that the vitamin can reduce the risk of heart disease and stroke. Given the results of other studies of vitamin D, there seems to be adequate reasons for individuals to maintain a healthy level of the vitamin.
Intermountain Medical Center news release, Nov. 16, 2009
Vitamin D Council