The Building Block of the Brain This omega-3 long chain fatty acid is the primary building block of the brain. The brain is 60% fat, and DHA is the most abundant fatty acid in the brain, comprising 25-35%. DHA is critical for infant development. Compelling research links DHA to the rapid cerebral that occurs during pregnancy and in the first few months after birth. DHA is vital for development of a baby’s brain, especially during the last three months of pregnancy. DHA makes up 10% - 15% of the weight of a baby’s cerebral cortex. DHA is so important to a developing baby that, during late pregnancy, the placenta extracts it from the mother’s own blood and concentrates them in her baby’s circulation. As a result, a baby’s levels of DHA are twice as high as his mother’s. If maternal levels of DHA are low, some DHA is also obtained from the mother’s richest store - her own brain. This may account for the slight shrinkage (2% - 3%) in maternal brain size seen in some pregnant women, and account for the poor concentration, forgetfulness and vagueness that many women experience during the last few months of pregnancy. A newborn baby is unable to produce DHA from essential fatty acids until he is at least 4 months old. He therefore depends on what he can obtain from breast milk or enriched formulas. Supporting a Healthy Nervous System DHA's benefits are not limited to infant development. Supplementation may be helpful to anyone with a low DHA intake, especially for supporting a healthy nervous system. DHA has been associated with optimal memory function, visual acuity, and maintaining a positive mental state. DHA is an integral component of all membranes with electrical activity. The cells in our brain, retina and other parts of the nervous system have a complex network of connecting arms that transport electrical messages throughout the body. DHA's presence in nerve cell membranes is critical because this is messages are transmitted. It is at the membrane that nerve cells perform their unique function of generating the electrical impulses that are the basis of all communication in the nervous system. Without the necessary fatty acids, this communication system can break down or become less effective. DHA supplementation may be especially important as we grow older. The body's ability to synthesize DHA, which is very limited in all human beings, may decline even further with age. Research suggests that aging interferes with the activity if delta-6-desaturase, the enzyme involved in the conversion of omega-3 fatty acids into DNA. Elderly people with inadequate or DHA-deficient diets may benefit from a supplementary source of DHA.