Fish may just be “brain food,” after all.

A growing literature of diet science has linked omega-3 fatty acids in seafood with greater intelligence, as well as better sleep. Now, a new study in Scientific Reports found linkage of the three factors in a group of Chinese children: the intake of omega-3s, resulting in improved sleep, which in turn produced better brain performance.

“It adds to the growing body of evidence showing that fish consumption has really positive health benefits and should be something more heavily advertised and promoted,” said Jennifer Pinto-Martin, executive director of the University of Pennsylvania’s Center for Public Health Initiatives, and an epidemiologist. “Children should be introduced to it early on.”

The study of 541 Chinese children, ages 9 to 11, started with a self-reported dietary questionnaire about the frequency of fish consumption, from never, to at least weekly.

The children then took the Chinese equivalent of an IQ test.

Afterward, the parents reported a standardized questionnaire about the sleep quality of their children.

The linkage was made in the numbers, and it began with the sleep reporting.

“More frequent fish eating was found to be independently associated with less sleep disturbances, which indicated better overall sleep quality,” they report.

The improved intelligence followed. Data analysis showed that the children who ate fish at least once per week had IQ scores 4.8 points higher than those kids who never ate fish. The children who ate fish occasionally but less than once per week had scores 3.3 points higher, according to the paper.

“Ideally, future randomized controlled trials which manipulate fish consumption and sleep will be launched to test the causal mechanism of the hypothesized model,” they write.

“This area of research is now well-developed. It’s emerging,” added Jianghong Liu, lead author of the study, from the University of Pennsylvania.

But while the links between seafood and better-performing brains continues to mount, the exact cause remains unclear. One of the most recent studies, from 2014 in the American Journal of Preventive Medicine, found that larger gray matter volumes from eating fish was not due to the omega-3 content in the meals.