A new study published in Childhood Obesity found that nearly one in six young patients, 16.8%, were diagnosed with a nutritional deficiency during the first year after starting GLP-1 treatment for weight loss, prediabetes, or type 2 diabetes.

GLP-1 medications are the drug class that includes liraglutide (Victoza and Saxenda), dulaglutide (Trulicity) and semaglutide (Ozempic and Wegovy). They work in part by reducing appetite, which is exactly why a pediatric nutrition question was always going to arrive eventually.

What the claims data show

The researchers analyzed national administrative claims collected from 2017 through 2022, drawn from a database covering more than 100 million patients. From those records they identified 2,031 GLP-1 users ages 10 to 17 who met continuous enrollment requirements and had no prior nutritional deficiency diagnosis.

Vitamin D deficiency was the most frequently identified problem, affecting 12.4% of children within one year of beginning therapy. Liraglutide dominated the prescribing picture at 78.6%, with dulaglutide at 10.4% and semaglutide at 9.1%, a distribution worth remembering the next time a headline about pediatric GLP-1 use is illustrated with a Wegovy pen.

Why adolescence is the pressure point

Senior author Justin Ryder, PhD, of Ann & Robert H. Lurie Children's Hospital of Chicago and Northwestern University Feinberg School of Medicine, said the field needs to understand the risks during periods of rapid growth and pubertal development. "Nutrients such as vitamin D, iron and calcium are of particular concern during adolescence, when deficiencies may have lasting implications for skeletal health and overall development," he said.

That framing matters. The same appetite effect that makes these drugs work in adults lands differently in a body still building bone.

The counseling gap

The most striking figure in the release is not the deficiency rate. Only 5% of patients received nutritional counseling within 30 days of starting a GLP-1, and fewer than 25% received it within six months.

Ryder said nutritional support needs to play a critical role once treatment is initiated, and the authors argue that care should begin alongside the prescription rather than after a deficiency has been detected.

Bottom line

The researchers say knowing the risks puts clinicians in a better position to prevent harm during a pivotal developmental window. What the study does not settle is how much of the deficiency signal reflects the drugs themselves versus what was already happening in this population.