Similar effects on infants of n-3 and n-6 fatty acids supplementation to pregnant and lactating women

Objective. There have been indications that high intake of n-3 long-chain p olyunsaturated fatty acids (PUFAs) during pregnancy may increase birth weig ht and gestational length. In addition, n-3 long-chain PUFAs may be importa nt for the neurobiological development of the infants. High levels of docos ahexaenoic acid (DHA, 22:6 n-3) are found in the gray matter of the cerebra l cortex and in the retina, and it seems as if the availability of long-cha in PUFAs may be limiting cerebral development. The fetus and the newborn ar e dependent on a high supply from their mothers, either via the placenta or via breast milk. We supplemented pregnant and lactating women with n-3 or n-6 long-chain PUFAs to evaluate the effect on birth weight, gestational le ngth, and infant development. Design. We performed a double-blind, randomized study recruiting 590 pregna nt, healthy, nulli- or primiparous women (19-35 years old) in weeks 17 to 1 9 of pregnancy. The women were provided 10 mL of either cod liver oil or co rn oil daily until 3 months after delivery. Main outcome measures. Primary outcomes were gestational length and birth w eight. Electroencephalography (EEG) was done on the second day of life and at 3 months of age. Novelty preference (Fagan test) was used as an indicato r of cognitive function at 6 and 9 months of age. The fatty acid pattern in umbilical plasma phospholipids and in breast milk was measured, and dietar y assessments were performed, both on the mothers during pregnancy and on t he infants at 3 months of age. The growth of the infants was followed up to 1 year of age. Results. Three hundred forty-one mothers took part in the study until deliv ery. There were no significant differences in maternal body mass index befo re pregnancy and at birth, or parity between the 2 groups. Smoking habits a nd parental education were also similar in the 2 groups. The mean age of th e mothers receiving cod liver oil was, by chance, 1 year higher than the ag e of the mothers receiving corn oil (28.6 [3.4] vs 27.6 [3.2] years). The m aternal dietary intake in the 2 groups receiving cod liver oil or corn oil was similar, except for the supplementation. There were no differences in g estational length or birth weight between the cod liver oil group and the c orn oil group (279.6 [9.2] vs 279.2 [9.3] days; 3609 [493] vs 3618 [527] g, respectively). Birth length, head circumference, and placental weight were also similar in the 2 groups. The concentrations of the n-3 fatty acids ei cosapentaenoic acid (20: 5 n-3), docosapentaenoic acid (22: 5 n-3), and DHA in umbilical plasma phospholipids were higher in the cod liver oil group c ompared with the corn oil group (10.8 [7.6] vs 2.5 [1.8] mug/mL, 5.0 [2.6] vs 2.9 [1.3] mug/mL, 55.8 [20.6] vs 45.3 [12.8] mug/mL, respectively). Neon ates with high concentration of DHA in umbilical plasma phospholipids (uppe r quartile) had longer gestational length than neonates with low concentrat ion (lower quartile; 282.5 [8.5] vs 275.4 [9.3] days). No differences in EE G scores or Fagan scores were found, but neonates with mature EEG (N = 70) had a higher concentration of DHA in umbilical plasma phospholipids than ne onates with immature EEG (N = 51) on the second day of life. Dietary inform ation from 251 infants at 3 months of age was collected and 85% of these in fants were exclusively breastfed, in addition to 12% who were partly breast fed. The breast milk of mothers supplemented with cod liver oil contained m ore n-3 long-chain PUFAs and less n-6 long-chain PUFAs than breast milk of mothers supplemented with corn oil. There were no significant differences i n infant growth during the first year of life between the 2 groups. Conclusions. This study shows neither harmful nor beneficial effects of mat ernal supplementation of long-chain n-3 PUFAs regarding pregnancy outcome, cognitive development, or growth, as compared with supplementation with n-6 fatty acids. However, it confirms that DHA concentration may be related to gestational length and cerebral maturation of the newborn.