MONDAY, May 22, 2006 (HealthDay News) -- Teens with low levels of vitamin D have lower lung function than those with recommended amounts, a new U.S. study finds.
Vitamin D is manufactured by the body upon exposure to sunlight, and the nutrient is also found in fortified dairy products, egg yolks, saltwater fish and liver. It is also added to some calcium supplements.
It's well-known that vitamin D plays an important role in bone health, because it helps the body absorb calcium. Recent research has also suggested that vitamin D may also be a factor in lung health.
The study of 2,112 adolescents, aged 16 to 19, found that 35 percent of the teens consumed less than the recommended amount of vitamin D per day (200 international units). Teens with a low intake of vitamin D (157 IU or less per day) had significantly lower lung function than those who consumed more, including the recommended amount. There was no difference between girls and boys.
"These are adolescents who should have optimal pulmonary function," lead researcher Jane Burns, a research fellow in the department of environmental health at Harvard University School of Public Health in Boston, said in a prepared statement.
"If they're already showing lower pulmonary function associated with lower vitamin D intake at this age, it may have long-term effects on their health," she said.
The study was expected to be presented Monday at the American Thoracic Society's international conference, in San Diego.
"Vitamin D is promoted in terms of bone growth, but we also need to think in terms of vitamin D's other effects on the body. It may well be that we should be promoting dietary vitamin D intake at recommended levels to ensure optimal lung function as well as to form and maintain healthy bones," Burns said.
Exactly what role vitamin D may play in lung health isn't clear, but it is known to affect the immune system.
"We don't know by which mechanism vitamin D affects pulmonary function -- it's an area that needs to be explored," Burns said.
The U.S. National Library of Medicine has more about vitamin D.