A six-year study led by Maria Makrides of Women's & Children's Health Research Institute and Bob Gibson of University of Adelaide has shown how high doses of fatty acids found in tuna fish oil administered to premature babies can help their mental development.
Researchers found that a major lipid in the brain - the omega-3 fatty acid known as Docosahexaenoic acid (DHA) - is not developed sufficiently in babies born before 33 weeks' gestation, leading to possible impaired mental development.
To counter this, increased doses of DHA (1,000 mg per day) were administered to lactating mothers with pre-term infants, found in tuna fish oil. If required, infants were given supplementary formula with matching DHA levels.
Of 657 premature babies tested in a trial involving five Australian hospitals, about 50 per cent fewer infants on high-DHA diets had significantly delayed mental development compared with low DHA diets.
Premature girls in particular who were exposed to DHA-rich diets showed much better mental development than girls fed the low DHA diet.
Gibson, a professor, said his team was at a loss to explain why premature male babies - who are more susceptible to cognitive problems - did not respond to the same extent, with no obvious differences in mental development between the control group and those administered high doses of DHA, said an Adelaide release.
"Boys may have a faster metabolic rate than girls and need higher doses of DHA to make a difference," he said. "We need to do a lot more work in this area to find out why."
Infants weighing less than 1.25 kg (about a third of a full-term baby's weight) who were fed a high-DHA diet also scored better on the mental development scale, with a 40 percent reduction in the incidence of mild mental delay.
The findings were published on Thursday in the Journal of the American Medical Association (JAMA).