Preterm Infant Lung Function May Benefit from Higher Levels of DHA in Breast Milk

It is often noted that the prevalence of atopic diseases has been increasing around the world for the past several decades. These conditions have been associated with Western lifestyles and diets, as well as environmental and genetic factors. Preterm delivery also increases the risk of atopic (IgE-associated allergies) diseases. The most common allergic diseases in early life are asthma, eczema and rhinitis (stuffy, runny nose). Studies on allergic conditions in infants and young children have examined the relationships between the mother’s fish or long-chain omega-3 fatty acid consumption in pregnancy and the development of allergic symptoms in the offspring. Long-chain omega-3s have anti-inflammatory properties and may affect the development of the immune system during fetal life. Some, but not all, of these studies have reported a lower risk of developing asthma in the offspring of mothers with higher intakes of fish or omega-3s, while others observed a lower occurrence of lung disease (bronchopulmonary dysplasia). Lung diseases in preterm and term infants often require treatment with oxygen. A new report from an Australian study of preterm infants describes the effects of providing two levels of DHA through breastfeeding to over 600 infants born before 33 weeks’ gestation. Participating mothers were given tuna oil capsules to increase their breast milk DHA concentrations to one of two levels. One group received DHA to reach the amount usually found in long-chain PUFA-supplemented infant formula. The other was given sufficient to reach the level found in Japanese mothers’ breast milk, about 1% DHA. A control group was given soybean oil supplements. The investigators monitored the infants for the occurrence of respiratory problems and allergic conditions. The infants received these feedings from shortly after birth until they reached their expected delivery date. When the infants reached 18 months of age, corrected for early delivery, their mothers were interviewed to determine the infant’s medical condition and treatments. Information about the infant’s need for oxygen treatment after delivery was also recorded. The occurrence of bronchopulmonary dysplasia did not differ between the two DHA-enriched groups considered as a whole. When the investigators examined the outcomes according to the infants’ birthweights, those weighing less than 1,250 grams (2 lb 12 oz) and males had a significantly lower need for oxygen therapy if they had received the highest DHA breast milk. The effect was not observed in female or heavier infants. Infants in the high DHA group also had fewer occurrences of hay fever at 18 months of corrected age. There were no differences in the occurrence of asthma, eczema or food allergy. These observations suggest that treatment of preterm infants with higher levels of DHA immediately after delivery may have beneficial effects on lung function and respiration, particularly in males, as seen in a reduced need for oxygen therapy after delivery and less hay fever at 18 months’ gestational age. The study did not report on markers of inflammation in these infants, so it is not known whether reduced inflammation might have contributed to these observations. But the study provides good support for robust provision of long-chain omega-3s to preterm infants, ensuring that DHA levels are closer to Japanese levels than most Western ones.