A recent study published in the American Journal of Epidemiology examined the relationship between what women ate while they were pregnant and the cognitive test scores of their children three years after birth.

The study results revealed that women who ate fish while pregnant gave birth to babies who by age 3 had significantly better cognitive and fine-motor skills than those whose mothers didn't eat fish during pregnancy.

The 3-year-olds from the women who reported eating more than 2 servings of fish per week performed better than average on tests that assessed receptive vocabulary and visual-spatial, visual-motor, and fine-motor skills.

This result is significant because the most important time of development for our brains is before we are born. Almost all of our neurons have been created by the time of our mothers' second trimesters, when the critical process of establishing the correct interconnections is taking place.

Our thinking, behavior, and cognitive abilities, of course, ultimately result from the functioning of our brains. Therefore, abnormalities in our brains that arise early in its development can result in abnormal thinking and behavior later on.

Why fish? Because fish is a rich source of particular health-promoting OMEGA 3 fatty acids that are known to be important components of the brain's structure.

There is a downside to eating fish while pregnant, however. Fish also can be a source of mercury, which has a devastating effect on brain development. In fact, the 3-year-olds from those women who had higher-than-average mercury levels when pregnant tended to score lower on the above tests.

Large, long-living fish such as tuna and swordfish, which feed on other fish and thus keep accumulating mercury, are the most likely to have elevated levels of the poison. Types of seafood that generally have low mercury levels include shrimp, sardines, and salmon.

Another study, published in a recent issue of the journal Pediatrics, demonstrated the benefits of similar fatty acids on brain development. Researchers gave premature infants milk supplemented with essential fatty acids. At the age of 6 months, the infants given the supplements scored better on development assessments than did similar premature infants given no supplements.

While fatty acids play an important role early on in the developing brain, they may also be important for brain and mental health throughout our lives. Scientists continue to explore their health-promoting effects, including whether they may prevent certain psychiatric disorders.