Weaning foods cannot replace breast milk as sources of long-chain polyunsaturated fatty acids.

Breast-milk lipids contain long-chain polyunsaturated fatty acids (PUFA) not found in infant formulas. Because the erythrocyte membranes of formula-fed infants are depleted in long-chain PUFA, we sought food sources of these 20- and 22-carbon polyunsaturates suitable for use as dietary supplements. A variety of commercially available infant foods containing meats and egg products in addition to some whole foods (meat, eggs) were analyzed by gas chromatography. Commercially available infant foods contained only low levels of long-chain PUFA. The richest source of omega-3 and omega-6 PUFA was found to be lamb brains but lamb and chicken livers as well as egg yolks also contained high levels. However, the lipid content of most whole foods including brains, eggs, and liver is so low that prohibitively large amounts of food would be required to be fed to infants. It is concluded that it is virtually impossible to supplement the diet of formula-fed infants to match the long-chain PUFA intake of breast-fed infants with currently available whole foods.