Because of the rapid rate of growth during infancy, and the potentially del
eterious effect of differences in the availability of dietary essential nut
rients, growth is an important outcome variable in any study assessing a di
et designed for infants. Nearly 10 yr after the first demonstration of redu
ced growth in preterm infants fed a fish oil-enriched formula, there is ver
y little additional information to confirm or refute the finding that long-
chain n-3 polyunsaturated fatty acid (LC-PUFA) intake can modulate growth i
n infants. To evaluate the issue of a possible relationship between PUFA in
take and growth of infants, we reviewed a total of 32 randomized studies, 1
3 in preterm infants and 19 in term infants. From the data published to dat
e, it seems clear that long-chain n-3 fatty acids can reduce growth achieve
ment in preterm and term infants under some experimental conditions. Howeve
r, the effect of n-3 PUFA supplementation on the growth of preterm and term
infants appears to be minimal and of questionable clinical and/or physiolo
gic relevance. Nonetheless, n-3 fatty acids have an effect on gene transcri
ption, at least in some species, and this finding may provide important clu
es to the mechanism by which n-3 and n-6 fatty acids regulate growth.