A new University of Pennsylvania School of Nursing study found that children who ate fish regularly scored nearly five points higher on a standard IQ test that measures cognitive function in children. The kids who favored fish over traditionally kid-friendly items, such as chicken fingers and fries, also slept better and had fewer sleep interruptions.

The study of 541 boys and girls in China, ages 9 to 11, who completed a questionnaire about how often they consumed fish in the past month, was published Dec. 21 in Scientific Reports.

The results found that those who said they ate fish once a week scored 4.8 points higher on the Wechsler Intelligence Scale IQ test than those who seldom or never included fish in their diets.

“This area of research is not well-developed. It’s emerging,” said Jianghong Liu, the lead author on the paper and an associate professor of nursing and public health, told the school’s Penn News. “Here we look at omega-3s coming from our food instead of from supplements.”

Even these children who ate fish only occasionally benefited with better verbal and non-verbal skills and scored an average of 3.3 IQ points higher than those who turned their noses up at fish. The link between omega-3 fatty acids that are found in fish — but not all kinds of fish — and better brain function has been found in many studies over the years.