the dish on
By Rukmini Deva
maternal diet lacking DHA may harm prenatal cognitive development
alking down an aisle at Whole Foods, “DHA” and “omega-3” labels adorn various food items including milk, eggs, nuts, flaxseeds and oils. What is this mystery substance, and why are grocery stores promoting it? Docosahexaenoic acid (DHA) is an omega-3 fatty acid critical for optimal brain health and function at the prenatal stage of development as well as later in life.1 Despite its importance as a key hormone in brain function, DHA levels are low in America. This national deficiency has led to the production of DHA-fortified baby formulas and prenatal vitamins. Dr. Carol Cheatham, a developmental cognitive neuroscientist at UNC-Chapel Hill’s Nutrition Research Institute, is working to understand the implications of this nationwide DHA deficiency. Specifically, her research focuses on the process and efficacy of DHA transfer from mother to child via both the placenta and breast milk.3 Although physicians have long touted the advantages of breastfeeding, Dr. Cheatham’s research shows how, without proper maternal diet, breastfeeding may not always provide some important nutrients. The explanation lies in the genotype of the mother. Seven percent of US women are genetically unable to synthesize DHA.3 Consequently, these women have less DHA in their blood plasma during pregnancy, resulting in a lower amount of DHA supplied to the fetus during its
brain development phase and after birth. “I don’t want women to think that breast milk is bad; I want to encourage breastfeeding. But if certain women are part of this seven percent, then they will have to eat plenty of DHA,” Dr. Cheatham said. DHA-fortified formula is commercially available, but clinical trials have not been able to prove that supplemental DHA has the same benefits as natural DHA; Dr. Carol Cheatham in fact, fewer than 40 percent of trials have found that it does. Moreover, physicians in the United States do not commonly test for reduced DHA levels in their patients.3 As a result, it is unlikely that a woman in America will know if she is part of the seven percent of females who cannot synthesize DHA. One way to correct a DHA deficiency is by reducing omega-6 intake and increasing omega-3 intake. Dr. Cheatham recommends that all pregnant women, regardless of their genotype, obtain exogenous sources of DHA and other omega-3 acids Figure 1. In one of Dr. Cheatham’s labs, a six month old named Lincoln participates in a unique study. His scalp covered in 128 electrically sensitive sponge cups, Lincoln sits quietly on his mother’s lap, watching a screen of blinking images. As Lincoln observes each passing image of a toy, the sensors create a graphical representation of his brain activity. Upon seeing new toys, Lincoln’s brain activity increases. When a familiar toy appears, however, the brain does not expend its energy to process the familiar toy again. Photo by Jon Lakey, Salisbury Post.
Spring 2014 issue of Carolina Scientific