September 2nd, 2011

Vitamin D is an important fat-soluble vitamin that is necessary for the human body. Vitamin D helps an individual stay healthy and aids in absorption of other nutrients, which may also help with cardiovascular conditions.

Take a look at this exerpt from the Philadelphia Inquirer:

Vitamin D has been much in the news in recent years, with books and articles touting its benefits for myriad medical conditions and the public responding with a 52 percent jump in use over just two years, according to one survey out last month.

So, does it help the heart?

The short answer: maybe.

True believers in the “sunshine vitamin,” including some researchers and holistically inclined physicians, point out that several cardiovascular conditions become more common the farther you live from the sun-drenched tropics. And a few studies have found that some heart-related ailments occur more often among people with lower levels of vitamin D in their blood.

More cautious public-health doctors, as well as a federal panel that updated guidelines in November, note that evidence of the vitamin D/heart-health link comes from a small number of studies. And they say megadoses are potentially risky.

Both sides agree there is no solid evidence that vitamin D supplements can prevent heart disease from developing or worsening. Since the evidence of harm from taking too much is squishy as well, for many patients a decision may come down to their comfort level with experimentation and risk.

Although the issues are complex, some statistics are tantalizingly simple. A recent Drexel University study, for example, cross-referenced vitamin D blood levels against heart-failure deaths over eight years in a national database of 13,131 adults.

After adjusting for age, sex, race and medical conditions at baseline, they found that people whose vitamin D levels were “deficient” were 3.4 times more likely than those with “normal” levels to die of heart failure prematurely (before age 75); people whose vitamin D levels were merely “insufficient” were two times more likely to die.

The critical importance of vitamin D for bone development has been clear for nearly a century, but nearly all the other potential benefits – for flu, diabetes, multiple sclerosis and numerous cancers, as well as heart disease – were discovered in the past two decades. With no records dating back to when humans lived outdoors and produced vitamin D the natural way, from sunlight, there is no consensus on how much is normal.

The Drexel researchers used common, but by no means universal, definitions for blood-serum levels measured by a 25-hydroxyvitamin D test: “Deficient” was less than 20 ng/mL, “insufficient” was 20-29 ng/mL, and “normal” was 30 ng/mL or more.

By those definitions, more than 55 percent of whites in the national sample were below normal, including 20 percent who were deficient; among blacks, nearly 90 percent were below normal, including more than 60 percent deficient.

Blacks have far higher rates of heart disease than whites. Still, a correlation does not prove cause and effect; some third factor could play a role in both heart failure and vitamin D levels.

“And we have no evidence that treating them [with vitamin D] offers any benefit,” said Howard Eisen, chief of cardiology at Drexel’s College of Medicine.

Eisen led the study and presented the findings in September at the Heart Failure Society of America’s annual meeting in San Diego. Yet he has not changed his practice at Hahnemann University Hospital – ordering vitamin D tests, for example, only for heart patients with conditions for which the link is clearer, such as osteoporosis.

Vitamin D, which is actually a hormone, has recently been found to regulate thousands of genes in different ways, offering several potential mechanisms for an effect on the heart. A key one is reducing inflammation. It also tends to inhibit deposits that stiffen arteries, and it improves insulin sensitivity. So it could play a role in various cardiovascular conditions.

When doctors at the Intermountain Medical Center in Utah searched their records for patients who had been tested for vitamin D between 2000 and 2009, they found strong correlations between lower blood-serum levels and greater likelihood of being diagnosed with coronary artery disease, heart failure, atrial fibrillation and peripheral vascular disease, as well as having had a previous heart attack and stroke.

Conditions considered risk factors for heart disease – hypertension, diabetes, high cholesterol – were similarly related, they reported in October in the American Journal of Cardiology.

Although this study also could not prove cause and effect, lead author Jeffrey Anderson said he has seen enough evidence of benefit for overall health that he recommends his patients take 1,000 to 2,000 IU of vitamin D a day, which is higher than new federal recommendations.

Read more about this here.