Investigators at Joslin Diabetes Center and Children’s Hospital Boston have revealed that a type of “good” fat known as brown fat occurs in varying amounts in children which increases until puberty and then declines. Brown fat is more common in children who are leaner.

The investigation used PET imaging data to record the amount and activity of brown fat in children, which, burns energy in comparison to white fat that stores it. The study was published in the Journal of Pediatrics.

Aaron Cypess, MD, PhD, an assistant investigator and staff physician at Joslin and senior author of the paper said:

“Increasing the amount of brown fat in children may be an effective approach at combating the ever increasing rate of obesity and diabetes in children.”

In the New England Journal of Medicine in 2009, Cypess’ team demonstrated for the first time that brown fat is metabolically active in adult humans. In the past it was believed that brown fat was only found in babies and children. Their investigation revealed it was found in between 3 and 7.5 percent of adults, with higher rates among women.

In the new investigation, the investigators examined PET scans that had been conducted on 172 children between the ages 5-21 at Children’s Hospital Boston. 44% of children had brown fat detected, with the rate being roughly around the same for girls and boys. Those aged 13 to 15 had the highest percentage of detectable brown fat and activity. In addition, body mass index (BMI) was collected inversely with brown fat activity, meaning that children who were slimmer had the highest brown fat activity.

The new study revealed outdoor weather temperature had no effect on brown fat activity, while the 2009 investigation of adults indicated brown fat was more active in cold weather. The authors explained, the increase in brown fat activity from childhood to adolescence and its inverse correlation with obesity indicates brown fat may play a important role in pediatrics metabolism, energy balance and weight regulation.

First author Laura Drubach, MD, of Children’s Hospital program in Nuclear Medicine and Molecular Imaging explained:

“We believe that the ability to non-invasively evaluate brown fat activity in vivo with PET imaging provides a better understanding of its prominent role in pediatric physiology, and may possibly provide insights into the treatment of childhood obesity.”

Cypess explained the goal is to primarily to look for nonpharmacological ways to raise brown fat activity, maybe by reducing the temperatures in homes where obese children live. Perhaps certain foods could also play a role in increasing brown fat levels, he said. If not, the development of new drugs might be the answer, he added.

In 2010 a Joslin investigation identified cells in mice that can be triggered to transform into brown fat.

Cypess added:

“We might be able to combat the obesity and diabetes epidemics if we find safe ways of increasing brown fat activity. This might be an additional tool in the fight.
br> However, there are still many questions to be answered. For example, it is not known whether the relationship between BMI and brown fat is that children have more brown fat because they are thin or if having more brown fat causes children to be thin.

That’s the billion dollar question, But we do know that brown fat is a core component of pediatric and likely adult metabolism.”

Written by Grace Rattue