People with anorexia have fat in bones

BOSTON, Feb. 11 (UPI) -- People with anorexia nervosa have strikingly high levels of fat within their bone marrow, U.S. researchers found.

Researchers at Children's Hospital Boston said their findings are based on MRI imaging of the knees of 20 girls with anorexia and 20 healthy girls of the same age.

"It's counter-intuitive that an emaciated young woman with almost no subcutaneous fat would be storing fat in her marrow," Dr. Catherine Gordon, the senior investigator and director of the bone health program at Children's Hospital Boston, said in a statement.

For the study, the knee magnetic resonance imaging images were read by radiologists who were unaware of the patient's clinical status. Compared with controls, the patients with anorexia had markedly increased fat content -- visualized as "yellow marrow" -- and less than half as much healthy red marrow in the lower thigh bone and upper shinbone.

"Bone formation is very low in girls with anorexia, and that's a particular problem because they are growing adolescents who should be maximally forming bones," Gordon said. "But because of the hormonal alterations induced by malnutrition, the bone marrow stops yielding the needed cells to form bone. Instead the stem cells are pushed toward fat formation."

The findings are published in the Journal of Bone and Mineral Research.