Some parents see fruit juice as a tasty way for kids to get their vitamins, while others think fruit juice may be as harmful to child health as soda. Researchers from the University of Washington School of Public Health looked at the link between fruit juice and weight gain in children, and discovered that there’s not much to worry about.

“We found that consuming one serving a day of 100% fruit juice was not associated with weight gain in children,” said Brandon Auerbach, who conducted the study as a graduate student in the School’s Department of Epidemiology. Dr. Auerbach is now a primary care physician at Harborview’s Adult Medicine Clinic.

The study was a systematic review and meta-analysis of eight studies on 100% fruit juice consumption and weight gain including 34,470 children under 18. The study used body mass index, or BMI, and something called the BMI z score, which statistically adjusts BMI according to age. Changes in the BMI z scores of 0.25 to 0.50 are generally considered to put the child at risk for obesity.

The analysis, published online March 23 in Pediatrics, found that for children ages 1 to 6, one daily serving of juice (6 to 8 ounces) was associated with a 0.087 unit increase in BMI z score and was not clinically significant. For children ages 7 to 18, 100% fruit juice consumption had no effect on BMI z score at all.

“Our results support the current guidelines from the American Academy of Pediatrics,” Auerbach said. “Children should have whole fruit when possible, but one serving or less a day of 100% fruit juice is okay for kids after age one.”

The study was a team effort, noted Auerbach, the study’s lead author. Jim Krieger, Diana Louden, Fred Wolf, Alyson Littman and Abigail Hikida – all from the UW School of Public Health – contributed to the research.