New research in teenagers links low levels of vitamin D to high blood pressure and high blood sugar, which can lead to ominous early health problems.
The sunshine vitamin is needed to keep bones strong, but recent research has linked vitamin D to other possible health benefits. The teen study confirms results seen in adults, linking low levels with risk factors for heart disease, the researchers said.
Teens in the study with the lowest vitamin D levels were more than twice as likely to have high blood pressure and high blood sugar. They were also four times more likely to have metabolic syndrome, defined as have three of more conditions that contribute to heart disease and diabetes – including high blood pressure, high blood sugar, big waists and high cholesterol.
The study s leader, Jared Reis of Johns Hopkins Bloomberg School of Public Health, said more research will be needed to determine if vitamin D is really behind the health problems and whether getting more would make a difference.
We re showing strong associations that need to be followed up, he said.
The findings were being presented Wednesday at an American Heart Association conference in Palm Harbor, Florida.
A former president of the heart group said there s much to be learned about the apparent connection.
We re at the tip of the iceberg, said Dr. Robert Eckel.
The body makes vitamin D when exposed to sunlight s ultraviolet rays.
Getting about 15 minutes of sunlight a few times a week is generally enough.
Vitamin D is also in fortified foods like milk and in salmon and other oily fish.
The American Academy of Pediatrics recently doubled its recommended amount of vitamin D for children and teens to 400 units daily – the equivalent of drinking four cups of milk. The pediatricians group said kids who don t get enough should take vitamin supplements.
The teen study looked at about 3,600 boys and girls ages 12 to 19 who took part in a government health survey from 2001 to 2004. The researchers used measurements of vitamin D from blood tests.
On average, none of the teens were getting enough vitamin D. Whites had the highest levels, blacks had the lowest levels and Mexican-Americans had levels in between.
One reason for the difference, experts say, could be that it takes fair skin less time to absorb vitamin D from the sun than darker skin. Also, Reis said, blacks may be skipping milk because they are more likely to be lactose intolerant.
Dr Randal Thomas, director of the cardiovascular health clinic at the Mayo Clinic in Rochester, Minnesota, said that it s likely that vitamin D deficiencies in teens stem from unhealthy diets and lack of exercise outdoors.
If their diet includes chips and soft drinks, they re probably not getting enough vitamin D, said Thomas.
Experts say there are many questions that still need to be answered about vitamin D, including how much people need.
As time goes on, we re getting a better idea of what we need and how it s functioning in our bodies, said Adrian Gombart, a vitamin D researcher at Oregon State University.
