Catherine Peterson of the University of Missouri said the Institute of Medicine recently set new dietary reference intakes for vitamin D -- 600 International Units per day, with a tolerable upper intake of 4,000 IUs, Peterson said.
In the study, participants -- deficient or insufficient in vitamin D -- were randomly selected to receive a placebo or 4,000 IU/day of vitamin D3 for six months as part of their standard treatment at the University of Missouri, Adolescent Diabetes and Obesity clinic.
Peterson told the annual meeting of Experimental Biology that the participants supplemented with vitamin D3 had significantly greater increases in concentrations of 25OHD -- the main indicator of vitamin D status -- compared to those who received the placebo. Obese adolescents are only about half as efficient at using vitamin D as their lean counterparts, the study said.
"If obese adolescents only consumed the recommended 600 IUs, they would be in trouble," Peterson said in a statement.
"It takes 4,000 IUs to raise their vitamin D status within a sufficient range. This is much higher than the currently recommended daily amount for this age group. This indicates that physicians need to carefully evaluate the vitamin D status in their overweight and obese patients."