Impact of solid food on plasma arachidonic and docosahexaenoic acid status of term infants at 8 months of age

We studied healthy term infants at 6 and 8 months of age to assess the effect of fat-containing solid foods (mashed veal, chicken, and pork provided in ready-to-feed cans) on plasma long-chain polyunsaturated fatty acid (LCP) status. Twenty-one infants were breast-fed and 49 were formula-fed. The fat of the formula contained 16.2% linoleic acid and 2.3% alpha-linolenic acid but no LCPs. The solid-food intake was assessed with a 7-day dietary record. Blood samples were obtained at 6 and 8 months of age, and the fatty acid composition of plasma cholesteryl esters (CE) and phospholipids (PL) were analyzed with capillary gas liquid chromatography. The solid food-derived fat intake was higher in the formulated than in the breast-fed group at 6 months, and it increased significantly in both groups (from 0.15 to 0.39 g/kg/day and from 0.24 to 0.43 g/kg/day in breast-fed and formula-fed groups, respectively). The relative plasma concentrations of arachidonic acid (20:4n-6) and docosahexaenoic acid (22:6n-3) were significantly lower in the formula-fed than in the breast-fed group at both 6 and 8 months. In the formula-fed group at 8 months, the proportion of solid food-derived fat correlated positively with plasma 20:4n-6, and the mean percentage of PL-20:4n-6 were 8.0% (95% confidence interval, 7.4-8.5) and 9.0% (8.3-9.7) in its lowest and highest quartiles, respectively. In the breast-fed group, solid food-derived fat intake had no effect on plasma 20:4n-6. The two groups were similar in that solid-food fat had no effect on plasma PL- or CE-22:6n-3. In conclusion, the introduction of meat containing solid foods to formula-fed infants increases their plasma 20:4n-6, but not to levels found in breast-fed infants. Further studies are needed to establish an optimal fatty acid composition of solid foods during weaning.