Weekly consumption of baked or broiled fish boosts brain health, regardless of its omega-3 fatty acid content, according to a new study by the University of Pittsburgh School of Medicine.

Lead investigator Cyrus Raji, who is in radiology residency training at UCLA, said that baked or broiled fish contains omega-3s in high amounts than fried fish because the fatty acids are destroyed in the high heat frying process.

Previous studies showed the anti-oxidant effects of omega-3 fatty acids on brain health. These acids are largely found in fish, seeds, nuts and certain oils.

"Our study shows that people who ate a diet that included baked or broiled, but not fried, fish have larger brain volumes in regions associated with memory and cognition," senior investigator James T. Becker, professor of psychiatry, said in a statement. "We did not find a relationship between omega-3 levels and these brain changes, which surprised us a little."

For the study, the researchers analyzed data of 260 people from the Cardiovascular Health Study (CHS) that began in 1989. The participants provided information on their dietary intake including the mode used in fish preparation and frequency of its consumption. They also underwent high-resolution brain MRI scans.

The researchers found that participants associated with baked or broiled fish consumption at least once a week had greater grey matter brain volumes in areas responsible for memory (4.3 percent) and cognition (14 percent). They were also more likely to attain college education than those who didn't eat fish regularly.

"This suggests that lifestyle factors, in this case eating fish, rather than biological factors contribute to structural changes in the brain," Becker said. "A confluence of lifestyle factors likely are responsible for better brain health, and this reserve might prevent or delay cognitive problems that can develop later in life."

The finding is published in the American Journal of Preventive Medicine.