The importance of fish oils and DHA before, during, and after birth.
There has been a rise in discussion concerning the use of omega-III fish oils by nursing and pregnant mothers. Docosahexaenoic acid (DHA) is an essential omega-III fatty acid responsible for many physiological roles. The human body cannot synthesize DHA from fatty acid precursors and therefore must be obtained through the diet. DHA is vital for brain development in fetal and infant stages as well as for the maintenance of normal brain function throughout life. Brain cells prefer DHA over all other fatty acids, making up one-third of all lipids in brain grey matter. So why is DHA so important? DHA containing phospholipids are necessary in the structural development of neural and synaptic membranes for cell signaling. Simply stated, DHA is required for brain cells to communicate properly.
During fetal development, maternal DHA is preferentially transported across the placenta and into fetal circulation. DHA accrues rapidly in the human brain during the third trimester of preganancy and during the early postnatal period. Maternal omega-III fatty acid stores are the sole source of DHA for the fetus as well as for exclusively breast-fed infants. DHA is the most abundant omega-III fatty acid in human breast milk. Due primarily to the less-than-average consumption of seafood and coldwater fish, American women have among the lowest levels of DHA in breast milk. Hence the recommendation for fish oil supplementation for pregnant and nursing mothers.
Currently in the United States, infant formulas do not require supplementation with DHA. If fact, it was only in 2001 that infant formula manufacturers were allowed to include DHA in their formulations. In Japan and most of Europe, infant formulas are routinely supplemented with DHA. The good news is that some premium infant formulas in the United States do contain DHA, and subsequently, other formula manufacturers will likely follow the trend. These formulas typically contain 8-17 mg of DHA per 100 kilocalories of formula.
Numerous clinical studies completed over the past few decades have strongly suggested the importance of DHA for brain development and cognitive function. Prenatal deficits in essential fatty acids, including DHA have been associated with low birth weight, small head circumference and small placental size. Further studies have shown that supplementing nursing mothers and infant formulas with DHA may lead to better cognitive function and visual attention later in life. A large scale study found that preterm infants receiving breast milk compared to those receiving non-DHA supplemented formula had an average 5-12 IQ points higher later in life. This number was 2-5 IQ points in full-term infants.
As the science behind DHA and fetal development becomes further elucidated, we will likely see a trend in infant formula manufacturers including DHA and other essential fatty acids as a major constituent of their formulas. Because there is a risk of heavy-metal contamination in fish oils, choose a reputable manufacturer who discloses the source of fish oils. Shellfish such as crab, shrimp, lobster and prawns is a desirable source. As always, it is recommended to consult your obstetrician concerning DHA during pre-, peri-, and postnatal periods.
