Kids need vitamin D for stronger bones, better blood pressure, lower cholesterol, healthier hearts and normal metabolism and are often deficient, in two new studies.

In a vitamin D and heart health study, researchers measured vitamin D levels and factors for cadiovascular problems in a nationally representative group of about 6,300 children, aged one to 21. About 9 percent of the kids-which would represent 8 million kids nationwide-were deficient in vitamin D, and 61 percent-representing another 51 million more-had too little vitamin D; 70 percent of all kids.

Vitamin D was most often low in kids who were older, female, obese, African-or Mexican-American, or who watched TV, played video games, or used computers for more than four hours per day. Doctors said the findings mean these children are more likely to develop high blood pressure and heart disease.

Kids with low or deficient vitamin D had signs of weaker bones, higher blood pressure, lower calcium levels, and lower levels of HDL, the good cholesterol, all key factors in heart disease, doctors said. Kids in the study who took vitamin D supplements, usually 400 IU per day, were more likely to have adequate vitamin D levels, but only 4 percent overall took supplements. "We expected the prevalence of vitamin D deficiency would be high, but the magnitude of the problem nationwide was shocking," study authors said.

In a related study, doctors measured vitamin D and heart disease factors in about 3,600 non-pregnant adolescents without diagnosed diabetes. African-American children had insufficient vitamin D levels on average, followed by Mexican-Americans, whose levels were barely sufficient. Caucasian kids had low but adequate levels. Kids with the lowest vitamin D levels were most likely to have high blood pressure, high blood sugar, and low HDL, and were about four times as likely to have metabolic syndrome(a precurser to Diabetes).

How can this be treated? Very simple, get your kids outside more. At least 10 minutes of sun per day without sunblock. It won't cause cancer in 10 minutes a day, and it should provide your children with adequate vitamin D production in their bodies.

Reference: Pediatrics, August, 2009, Electronic Pre-publication