MONDAY, March 29, 2010 (HealthDay News) -- Vitamin D deficiency is a common health problem around the world, experts say, and the problem may be especially severe in the United States among poor black and Hispanic children, researchers report.
In fact, about 74 percent of these children had less than optimal vitamin D levels, the study found.
"This is one of many studies pointing to the critical need for both children and adults to take supplemental vitamin D," said Samantha Heller, a dietitian, nutritionist and exercise physiologist from Connecticut who was not involved in the study. "Recent research has demonstrated that vitamin D deficiency is common in children and adolescents in the U.S."
The study "highlights the need for special attention to be paid to low-income children and minorities," she said. "Their vitamin D levels need to be checked regularly."
"All in all, it would seem reasonable -- in fact, urgent -- to recommend vitamin D supplementation for children," Heller said.
Another expert agreed.
Dr. Michael Holick, professor of medicine, physiology and biophysics and director of the General Clinical Research Center at Boston University Medical Center called the findings, "no surprise at all."
Holick noted that across the United States, up to 70 percent of children aren't getting enough vitamin D.
"African American and Hispanic children are at especially high risk," he said, because darker skin acts like a natural sunscreen. The ability to make vitamin D is reduced from 80 to 99 percent in darker skin, Holick said.
Vitamin D is essential for bone growth and other important metabolic functions, and she said that low levels in children can lead to health problems, including later in life. Experts currently recommend intakes of between 200 to 400 international units (IU) per day of vitamin D.
"Low vitamin D levels in U.S. adolescents are strongly associated with hypertension and hyperglycemia and metabolic syndrome, which can lead to type 2 diabetes," Heller said. "Parents must be informed of the need for vitamin D in children and the consequences of low vitamin D levels.
"Vitamin D is not in many foods," she said. "Foods fortified with vitamin D include ready-to-eat cereals, milk and some yogurts. Vitamin D is naturally found in fish such as salmon."
For the study, published online March 29 in Pediatrics, a research team led by Dr. Conrad R. Cole, an assistant professor of pediatrics at Emory University in Atlanta, looked at vitamin D levels in 290 Hispanic and black children from mainly low-income families in the metropolitan Atlanta area. The children averaged 2½ years old.
Earlier studies have found low vitamin D levels among children in northern climes, and the researchers wrote that they wanted to see whether the condition existed among children in the sunnier southern U.S. as well.
They found that about 22 percent of the children had low levels of vitamin D3, 74 percent had less-than-optimal levels of 25-hydroxyvitamin D and about 1 percent had low levels of calcium.
The greatest vitamin D deficiency was among black children, with 26 percent affected, compared with 18 percent of Hispanic children, the researchers noted.
Age was also a factor in vitamin D deficiency, Cole's group found, with older children less likely to have vitamin D deficiency. In addition, children who enrolled in the study in the spring and summer were also less likely to be vitamin D deficient, reducing the problem by about 20 percent.
More Hispanic than black children drank milk fortified with vitamin D, which provided 62 percent of the children's vitamin D intake, the study found.
"Children with suboptimal vitamin D status are at increased risk for bone disease, infections and other diseases," Cole said. "Parents should be educated about the importance of vitamin D and the source of vitamin D -- sunlight and fortified food sources. Minority low-income children who are at risk should be screened during the fall and winter."
And the findings point out that "vitamin D deficiency is not uncommon in the southern U.S.," he said.
The U.S. Office of Dietary Supplements has more on vitamin D.