By Margarita Nahapetyan
Two Adelaide-based researchers Dr Maria Makrides, B.Sc., B.N.D., PhD from the Women's & Children's Health Research Institute and Professor Bob Gibson from the University of Adelaide have made a world breakthrough when they have boosted the brain function of premature female babies by increasing the amount of an omega-3 fatty acid (known as DHA - docosahexaenoic acid) in either infant's formula or breast milk.
DHA is a long-chain omega-3 fatty acid, one of the essential nutrients required for the brain development. More than half of our brain consists of fat, one-fourth of which is DHA. Premature infants are often born before their brains have fully developed and they may lack adequate DHA while their brains are still growing. Breast milk and infant fortified formula contain DHA, but some scientists think that the amount might be insufficient and with some addition of fatty acid the mental development of preemie infants could be greatly improved.
The research team from the University of Adelaide conducted their study on 657 infants born before 33 weeks' gestation over a six-year period. Of all infants enrolled, 93.5 percent completed the eighteen-month follow-up. Doctors randomly assigned one half of the babies to a high-DHA diet (approximately 1 percent total fatty acids) and another half to a standard one (approximately 0.3 percent total fatty acids). For the diet high in DHA, lactating mothers took six 500-milligram tuna fish oil capsules per day to achieve a high breast milk DHA concentration and, if required, babies received supplementary infant formula. Mothers of babies on the standard diet took six 500-mg placebo soy oil capsules that did not change the fat content or fatty acid composition of their milk.
Each baby was examined from the child's due date to 18 months. The Bayley Mental Development Index (MDI), which evaluates the baby's memory, problem solving, early number concepts, alertness, curiosity, ability to do simple tasks for a reward, and language, was used to measure neurological development in newborns. Doctors found that the average MDI score did not differ between a high-DHA and a standard-DHA groups, but they noticed that the MDI score among girls who were fed the high-DHA diet was much higher than among girls fed the standard-DHA diet. The results showed that preterm baby girls weighing less than 1250gm (approximately one third of a full-term baby's weight) who were being given a high-DHA diet improved their mental development test scores by 5 points, in other words the incidence of mental delay was reduced by 40 to 50 percent. Infants who took a high-DHA diet also scored better on the mental development scale, and were 83 percent less likely to have a severe mental delay.
The MDI score among boys did not differ at all between the control group and those administered high doses of DHA. "The lack of responsiveness of boys to the intervention is puzzling, and the reasons are unclear ..." the authors wrote. Researchers said their team was surprised and could not explain why premature baby boys, who are considered to be more susceptible to cognitive problems, did not respond and react in the same way, with no obvious differences in mental development. "We can only speculate that there are differences in the metabolism of boys and girls that we do not yet understand," Dr. Makrides said. "The higher metabolic rate in boys may mean that they utilize much of the DHA they receive into energy. Also, boys may have a higher requirement for DHA. Clearly, this is an area of important research for the future."
Samantha Heller, a New York City-based registered dietitian, also said that she could not explain why there was such a difference between girls and boys in this study. She explained that DHA is really very important for the brain development in the womb and that previous studies showed how taking supplements in mid-pregnancy helped to improve baby's outcomes." So, what pregnant women can do is focus on their diets, before getting pregnant and during pregnancy, and include foods that have omega-3 fatty acids, like low-mercury fish," she said. "Some examples are anchovies, catfish, canned salmon, sardines, Pacific sole, tilapia, freshwater trout and whitefish."
The best source of DHA is seafood. Sources of DHA that are also known as the best are fish such as tuna, herring, salmon, and some organ meats. It can also be found in canola oil, walnuts, leafy green vegetables and flax oil. Besides fish, like salmon, sardines, and tuna, DHA is also present in eggs and meat. The fish oil with its significant component omega-3 fatty acid improves brain power, helps with major depression, schizophrenia, and postpartum depression, it is also a known fact now that fish oil helps to reduce chances of developing Alzheimer's. Besides, studies have shown that people who eat a minimum of 10 grams of fish per day have much better scores on mental tests than those who restrict themselves.
The project was funded by the National Health and Medical Research Council, with the University of Adelaide and Women's and Children's Health Research Institute (WCHRI).
SOURCES: Maria Makrides, B.Sc., B.N.D., Ph.D., deputy director, Women's and Children's Health Research Institute, and professor of human nutrition, University of Adelaide, Australia; Samantha Heller, M.S., R.D., New York City.
The study was published on January 14 in the Journal of the American Medical Association (JAMA).