The benefits of fatty acids such as docosahexaenoic acid (DHA) to growing infants have been highlighted several times this year on this site, not least because the recent approval of DHA-enriched baby foods by the Food & Drug Administration has led to a raft of such products being launched.
But new scientific research from Australia published in the American Journal of Clinical Nutrition shows that there are other sources of iron and DHA which offer an alternative to enriched formulas - namely egg yolks.
The researchers, led by Maria Makrides from the Child Nutrition Research Centre at the Women's and Children's Hospital in North Adelaide, studied the nutritional value of including two different varieties of egg yolks as weaning foods for a group of breast-fed and formula-fed infants and found that egg yolks provided advantages to both groups, with no negative effects on cholesterol concentrations.
The 137 mother-infant pairs in the study were recruited through immunisation clinics in and around Adelaide, and the six-month-old infants were randomly assigned to receive either no dietary intervention (control), regular eggs, or eggs that had been enriched by feeding hens diets rich in omega-3 fatty acids such as DHA.
Makrides' team took blood samples at six months and 12 months of age in order to measure the levels of DHA in red blood cells, as well as the levels of iron and plasma cholesterol.
In both the breast-fed and formula-fed groups, infants who consumed omega-3 fatty acid-enriched egg yolks had 30 to 40 per cent greater red cell membrane DHA levels than those fed regular egg yolks. There was no effect of omega-3 fatty acid enriched egg yolks on plasma cholesterol, but plasma iron levels were increased, the study showed.
The researchers claimed that the advantages of egg yolks for weaning purposes included their practicality and palatability as a food for infants, a modest improvement in iron status, and - in the case of omega-3 enriched eggs - a means of increasing dietary DHA without negative effects on cholesterol levels.
The authors suggested that future research in the field be directed toward determining the physiological benefits of enhancing DHA in the latter part of infancy.
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