Private MD News

Huge Vitamin D study planned

Category: Vitamin D Deficiency-Diagnosis and Treatment

A large, government-sponsored study to determine if vitamin D supplementation can lower a healthy person's risk of getting cancer, heart disease or having a stroke, will begin enrollment in January.

The study is called the Vitamin D and Omega-3 Trial, or VITAL, and is sponsored by the National Institutes of Health. It will enroll 20,000 people, one quarter of whom will be black. People with dark skin have difficulty making vitamin D from sunlight, and some researchers think that this may explain why they also have higher rates of cancer, stroke and heart disease.

"If something as simple as taking a vitamin D pill could help lower these risks and eliminate these health disparities, that would be extraordinarily exciting," lead researcher Dr JoAnn Manson of the Brigham and Women's Hospital in Boston told the Associated Press.

The Institute of Medicine recommends 200-600 international units of vitamin D per day. The VITAL study will test the effects of giving people 2,000 international units a day in supplements, substantially more than the 400 international units studied in the Women's Health Initiative, which found no significant benefits for colorectal cancer.

"We're hoping to see a result during the trial, that we won't have to wait five years" to find out if supplements help, Manson said.

Vitamin D is good target for intervention, say researchers, because the blood tests to detect it are fairly simple and dietary supplements are easy to take. Sunlight is also a simple way to produce more.

The exact link between vitamin D and disease is unclear and has not yet been put to a rigorous test, but evidence of many health effects has been building for years. Low levels are linked to ill health effects, and higher levels are often associated with better outcomes.

Cancer rates are higher in many northern regions where sunlight is weaker in the winter. Some studies have found that people with lower blood levels of vitamin D are more likely to develop cancer. Others link its anti-inflammatory effects with protection against heart disease.

Studies have shown that three-quarters of U.S. teens and adults are deficient in vitamin D, which is a dramatic increase from just 10 years ago. Some studies show up to 97 percent of blacks in the country are deficient.

Researchers also plan to study whether these nutrients help prevent memory loss, depression, diabetes, osteoporosis and other problems. Researchers in Australia have also found evidence of a genetic link between the inability to metabolize the vitamin and multiple sclerosis.

There have been numerous links between vitamin D levels and cardiovascular disease, although the mechanism isn't certain since it seem to affect almost all aspects of cardiovascular health.

A study published in 2008, published in the Annals for Internal Medicine by the Harvard School of Public Health, evaluated more than 18,000 men and found that men with vitamin D deficiency are twice as likely to suffer a heart attack as males with normal amounts of the vitamin.

A study presented at the National Lipid Association Annual Scientific Session earlier this year found that every 10 ng/dL increase of vitamin D in the blood was associated with a rise in blood levels of HDL, the good cholesterol, and a decrease in the occurrence of the metabolic syndrome, which has been linked to heart disease and stroke.

The link between vitamin D and cancer has been theorized to be due to antioxidant protection, but another theory states that low blood levels of vitamin D interfere in the communication between cells which keeps them in sync with each other and the body.