Quick Study

Tuesday, March 10, 2009


Sunshine vitamin may offer some protection.

THE QUESTION Some believe that Vitamin D, the nutrient most often linked to calcium and the maintenance of strong bones, might also help prevent colds. Is such a belief grounded in fact?

THIS STUDY analyzed data on 18,883 people, age 12 and older, including tests that measured levels of Vitamin D in the bloodstream. About 19 percent reported having had a cold within a few days of their starting the study. People with the lowest levels of Vitamin D (less than 10 nanograms per milliliter of blood) were 36 percent more likely to have had a recent cold, regardless of the time of year, than were those with the highest levels (30 or more nanograms). Risks were greater for people with asthma and low Vitamin D levels; they were five times more likely to have had a cold than those with the most Vitamin D.

WHO MAY BE AFFECTED? People with low levels of Vitamin D, which the body takes in through exposure to sunshine (15 minutes several times a week is recommended) and from food (egg yolks, saltwater fish, liver and fortified milk) or supplements. Most people need the equivalent of 400 to 600 international units of Vitamin D daily.

CAVEATS The study did not prove that low levels of Vitamin D cause colds; it could be that Vitamin D levels drop when someone has a cold.

FIND THIS STUDY Feb. 23 issue of Archives of Internal Medicine.

LEARN MORE ABOUT the common cold at http://www.lungusa.org and http://www3.niaid.nih.gov.


Lifestyle issues may play a role in stroke development.

THE QUESTION Might unhealthy living make stroke more likely?

THIS STUDY involved 20,040 adults (average age, 58) who were rated on four healthy lifestyle behaviors: not smoking, being physically active, drinking alcohol in moderation and consuming five servings a day of fruit and vegetables. None of the participants had had a stroke when the study began, but in an 11 1/2 -year span, 599 were hospitalized with a stroke. People who exhibited one or none of the healthy behaviors were more than twice as likely to have had a stroke as were those credited with all four.

WHO MAY BE AFFECTED? People of middle age and older, when strokes are most apt to occur. The risk more than doubles each decade after age 55, and about 75 percent of all strokes occur in people older than 65. In the United States, blacks are more likely to have a stroke than members of any other racial group.

CAVEATS Nearly all participants were white. The study did not differentiate between types of stroke, nor did it include people who may have had a mild stroke but were not admitted to a hospital.

FIND THIS STUDY Feb. 19 online issue of BMJ.

LEARN MORE ABOUT stroke at http://www.ninds.nih.gov and http://www.stroke.org.


Calcium may have an effect on digestive cancers.

THE QUESTION Calcium helps build strong bones and teeth and helps muscles and blood vessels expand and contract. Might it also help the body fight off cancer?

THIS STUDY analyzed data on 492,810 people of middle age and older. In a seven-year span, cancer was diagnosed in 53,570 of them. Overall, calcium intake from foods and supplements had little effect on the occurrence of cancer. However, people who took in the most calcium (up to 1,300 milligrams a day, on average) had the fewest cancers of the digestive track, with men in this group 16 percent less likely and women 23 percent less likely to develop digestive cancers, especially colorectal cancer, than were those who took in the least amount of calcium. No link was found between calcium intake and breast or prostate cancer.

WHO MAY BE AFFECTED? Middle-age and older adults. It's recommended that people older than 50 take in 1,200 milligrams of calcium daily. Milk, yogurt and cheese are the main sources of calcium for most people, but it also can be obtained through some green vegetables and fortified food and drink as well as supplements.

CAVEATS Data on calcium consumption were based on the participants' answers to questions about food, beverage and supplement consumption in the past year. Other studies have shown a link between high intake of calcium (2,000 mg or more a day) and prostate cancer, but this study found no such connection.

FIND THIS STUDY Feb. 23 issue of Archives of Internal Medicine.

LEARN MORE ABOUT calcium at http://www.ods.od.nih.gov. Learn about cancer at http://www.cancer.org.

-- Linda Searing

The research described in Quick Study comes from credible, peer-reviewed journals. Nonetheless, conclusive evidence about a treatment's effectiveness is rarely found in a single study. Anyone considering changing or beginning treatment of any kind should consult with a physician.

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