Adding long chain polyunsaturated fatty acids (PUFAs) to infant formula milk has no significant effect on either cognitive and motor development or on growth in full-term infants. This is the conclusion of a study by Professor Alan Lucas (Medical Research Council childhood nutrition research centre) and colleagues, who report their results in the Lancet (1999;354:1948).
The efficacy of long chain PUFAs in improving infant development has been debated for some time (see PJ 1998;261:659). Arachidonic acid and docosahexaenoic acid, both of which are present in breast milk, are the two that have received most attention. Professor Lucas and colleagues studied three groups of full-term babies - 155 who received standard formula feeds, 154 who received feed supplemented with both arachidonic and docosahexaenoic acids and 138 who were breast-fed and acted as controls. Babies not withdrawn from the study all received the allocated milk until they were six months of age.
The authors found no difference in overall developmental scores at nine months or 18 months and there were no significantdifferences between the groups in the incidence of atopy or infection. Head circumference at 18 months was lower in both formula-fed groups than it was in the breast-fed group. The authors comment that the median crying time of infants given the supplemented formula feed was longer than in the other groups but that this trend did not reach significance.
The researchers conclude: "Our study on healthy formula-fed infants . . . has failed to show efficacy for long chain PUFA supplementation of formula, in terms of effects on global measures of mental and motor development".
Dr Robert Gibson (child nutrition research centre, Flinders medical centre, Australia) writes in a commentary on the article (ibid, p1919) that, although these supplements appear to be safe, there is insufficient evidence to conclude that they improve the development of term infants. He describes any benefits conferred by long chain PUFAs as being less than those achieved by breast feeding.