Findings constitute strong evidence; heart outcomes tracked people's vitamin D blood levels closely; clinical trials needed to confirm results
by Craig Weatherby
Last fall, a team from Utah made headlines with the results of a large population study.
- Large, one-year study using blood tests linked vitamin D to heart health in a dose-response fashion.
- Among more than 9,400 mostly female patients, almost half of those who raised their vitamin D levels showed reduced heart risk.
- Among 31,000 volunteers, those who raised their vitamin D levels to 43 ng/mL or higher had lower rates of death, diabetes, cardiovascular disease, heaert attacks, heart failure, high blood pressure, depression, and kidney failure.
After following 27,686 Utah residents for more than a year, those with the lowest blood levels of vitamin D had the worst cardiac health outcomes:
- 77 percent more likely to die
- 45 percent more likely to develop coronary artery disease
- 78 percent more likely to have a stroke
- Twice as likely to suffer heart failure
The results were unusually reliable for an epidemiological study, thanks to the very low rates of tobacco and alcohol use among the Utah residents… leaving those heart-risk factors out of the equation (See “Low Vitamin D Linked to Heart Disease and Depression).
Now, the same Utah team has presented compelling new findings… ones that further support the idea that vitamin D is critical to heart health.
“Vitamin D… has long been associated with reducing the risk of fractures and diseases of the bone,” says Dr. J. Brent Muhlestein, MD, director of cardiovascular research at the Intermountain Medical Center Heart Institute.
“But our findings show that vitamin D could have far greater implications in the treatment and reduction of cardiovascular disease and other chronic conditions than we previously thought.”
Utah study links vitamin D to heart outcomes
According to the authors of two new studies from the Intermountain Medical Center Heart Institute in Murray, Utah, enhancing heart health in some patients could be as simple as supplementing their diet with extra vitamin D.
|Fish fit the vitamin D bill; Sockeye salmon stand out|
In addition to getting vitamin D from supplements, certain fish rank among the very few substantial food sources of vitamin D, far outranking milk and other D-fortified foods.
Among fish, wild Sockeye Salmon may be the richest source of all, with a single 3.5 ounce serving surpassing the US RDA of 400 IU by about 70 percent:
Vitamin D per 3.5 ounce serving*
Sockeye Salmon—687 IU
Albacore Tuna—544 IU
Silver Salmon—430 IU
King Salmon—236 IU
*For our full test results, click here.
The Utah researchers followed two groups of patients for an average of one year each... and they used different approaches in each group, which provided extra insights.
More than 9,400 patients, mostly female, reported low initial vitamin D levels, and had at least one follow up exam during that time period.
Researchers found that 47 percent of the patients who increased their levels of vitamin D between the two visits showed a reduced risk for cardiovascular disease.
The researchers followed some 31,000 patients, and thosewho increased their vitamin D levels to 43 nanograms per milliliter (ng/mL) of blood or higher had lower rates of death, diabetes, cardiovascular disease, heaert attacks, heart failure, high blood pressure, depression, and kidney failure.
Currently, a level of 30 nanograms per milliliter is considered normal, but most experts recommend minimum blood levels ranging from 36 to 48 ng/mL (90 to 120 nmol/L).
Study co-author Heidi May, Ph.D., said the link between low levels of vitamin D and increased risk for a variety of diseases is significant: “It was very important to discover that the ‘normal' levels are too low. Giving physicians a higher level to look for gives them one more tool in identifying patients at-risk and offering them better treatment” (IMC 2010).
Dr. Muhlestein says the results of these studies will change the way he treats his patients: “Although randomized [clinical] trials would be useful and are coming, I feel there is enough information here for me to start treatment based on these findings” (IMC 2010).
Dr. Muhlestein supports vitamin D intakes ranging from 1000 to 5000 international units (IU) a day, and notes that supplements are the easiest source.
Fatty fish like tuna and salmon are the best food sources by far, with albacore tuna and sockeye salmon leading the list. However, farmed salmon fall far short of the levels found in their wild counterparts (see “Wild Salmon Beats Farmed for Vitamin D... Again”).
- American College of Cardiology 59th annual scientific session, Atlanta, Ga., March 16, 2010
- Intermountain Medical Center (IMC). Studies find treating vitamin D deficiency significantly reduces heart disease risk. March 15, 2010. Accessed at http://www.eurekalert.org/pub_releases/2010-03/imc-sft031010.php