If recent news about mercury levels in fish and recommendations about adding this heart-healthy staple to our diet is confusing enough, here’s some food for thought. The same fish we’re warned against and those still considered safe to eat in bigger portions actually provide our brains with essential omega-3 fatty acids.
The omega-3 fatty acid in our brain called docosahexaenoic acid (DHA) plays an important role in brain development and function, and can only be obtained through our diet. And compared to people in other countries, says UC psychiatry researcher Robert McNamara, PhD, American diets are suffering from a DHA deficit.Fear of mercury and dietary trends in the U.S. have really impacted the amount of omega-3 fatty acid-rich foods that we consume on a daily basis, says McNamara. Omega-3 fatty acids, particularly DHA, can be found in high levels in fatty fish, including salmon, trout and tuna.A recent committee assembled by the American Psychiatric Association evaluated published data on the link between omega-3 fatty acid consumption and major mental disorders and concluded that omega-3 fatty acids could potentially be a safe and effective treatment for depression and bipolar disorder. They say further studies are warranted.But it’s the DHA we stock up on during critical periods of brain development that McNamara is so intrigued by. Lack of this fatty acid during brain development is associated with deficits in brain dopamine and serotonin levels which may contribute to attention problems and depression in young children, he says.McNamara is now conducting a study to find out if adding back DHA in the form of a fish-free supplement to the diets of young children can reverse DHA shortfalls and associated activity in brain regions involved in attention.For babies in utero, their only source of DHA is their mother, he says. After birth, an infant’s DHA comes from breast milk or fortified-formula. If moms aren’t getting enough DHA, then the child’s developing brain will be deficientAnd, he says, DHA-fortified formula did not become commercially available in the U.S. until 2002.Brain gray matter expansion continues until about the age of 12, says McNamara. Knowing that, he hypothesises that adding DHA to diets of children under 12 may be a way to restock this fatty acid in their brains, impacting cognitive function.McNamara is currently studying 8- to 10-year-old right-handed boys over the course of two months. Some will receive fish-free DHA supplements and others will receive a placebo. A functional MRI (fMRI) test will be given at the beginning and end of the study to gather information about brain activity and metabolism during attention tasks. The study is specific to right-handed boys, McNamara says, because handedness makes a difference in which brain hemisphere researchers monitor.We hope to determine whether dietary DHA intake can improve brain activity and function, says McNamara.(Source: University of Cincinatti: June 2006).