Infants with Higher Long-Chain Polyunsaturated Fatty Acids Have Fewer Illnesses

It is well known that infants born before term have a greater likelihood of developing illnesses and developing more slowly; the earlier the birth, the greater the health risks. There is growing evidence that preterm infants provided with long-chain polyunsaturated fatty acids (LC-PUFA) from breast milk or special infant formula have improved neurodevelopmental outcomes, such as visual acuity, growth or developmental scores. Breast-feeding is recommended, and if that is not possible, LC-PUFA-supplemented formula should be provided. In both term and preterm infants, healthy development is promoted if these fatty acids are abundant. There have been reports that infants whose mothers received DHA in pregnancy are less likely to develop infectious illnesses. DHA is a long-chain omega-3 fatty acid found mainly in fish, fish oil and egg yolk. Some evidence also suggests that school-age children have fewer respiratory illnesses if they were given DHA as toddlers or school-age children. What is new is the addition of infectious illnesses to the list of health conditions infants, especially those born preterm, may incur. In this article, two reports describe the illness outcomes in infants whose mothers consumed DHA or whose PUFA status was measured at birth. The first examined the occurrence and duration of several illnesses in term infants whose mothers consumed the recommended amount of DHA (200 mg/day) during the last half of pregnancy. The findings were compared with illnesses in infants whose mothers were given a placebo. At 1-month of age, the infants of DHA-supplemented mothers were more likely to have cough, phlegm and wheezing of shorter duration compared with the infants of the placebo mothers. Surprisingly, the DHA infants had longer times for rash compared with the placebo infants. When the infants reached 6 months of age, those whose mothers took DHA spent significantly less time having nasal secretion, difficult breathing, fever and rash compared with the placebo infants. These results suggest that DHA consumed in pregnancy might contribute to the shorter duration of certain common childhood symptoms, have diverse effects and may be effective at least until 6 months of age. The second study focused on preterm infants who are at high risk of developing retinopathy of prematurity (eye disease), sepsis (blood infected with bacteria), chronic lung disease and several others. On average, the infants were born at 27 weeks of gestation. Term gestation is 37 to 40 weeks. Blood was obtained at birth. All infants were fed intravenously with a mixture lacking LC-PUFAs. After 2 weeks of parenteral nutrition, the levels of arachidonic acid and DHA observed at birth declined significantly and remained low. Levels of linoleic acid increased significantly. Two clinical illnesses were related to the infants’ LC-PUFA status at birth. The risk of developing chronic lung disease was significantly greater in infants with low DHA and the risk of late-onset sepsis (3 days after birth) was higher in infants with low arachidonic acid levels and higher linoleic acid. These two fatty acids belong to the omega-6 family. These observations in high-risk infants suggest that susceptibility may be related to the infant’s LC-PUFA status at birth. Higher levels of DHA and arachidonic acid were associated with lower risks of chronic lung disease and late-sepsis. Because these fatty acids fell dramatically within the first week after birth when parenteral feeding was begun, the observations suggests that such feeding may enhance the risk of serious illness in preterm infants who do not receive LC-PUFAs. Together, these studies suggest that the risk of various infant illnesses may be increased in infants with low LC-PUFA status. This is of particular concern in high-risk preterm infants who are born without stores of these fatty acids and have missed the transfer of these PUFAs in the last trimester. Although more robust and extensive data are required before firm recommendations for preterm feeding can be made, one European pediatric society has issued recommendations for DHA and arachidonic acid intakes in preterm infants. One hopes these studies add impetus for obtaining the evidence needed to support LC-PUFA recommendations for preterm infant feeding.