Lipids for infant formulas

Abstract

Recommendations for infant formulas (IF) had been established on the basis of human breast milk composition, still considered as "the gold standard". Historically, till the 20th century, cow milk-based formulas have been used to feed infants when breast feeding was not possible. Later, infant formulas based on cow's milk proteins but only vegetable oils blends as lipid source became the usual rule in most countries. However, considering "the gold standard", a lot of changes occurred since the sixties that considerably modified lipid composition of human breast milk which is correlated to the diet of the mothers, who increased their consumption of n-6PUFA to replace saturated fat considered as proatherogenic. This introduced an imbalance in the ratio of linoleic/alpha-linolenic acids (18:2n-6/18:3n-3), limiting the bioconversion to long-chain-n-3 docosahexaenoic acid (DHA, 22:6n-3). Compared to pure vegetable blends and following the usual recommendations for IF, linoleic (LA 15% of total fatty acids), alpha-linolenic acids (ALA 1.5%) and LA/ALA ratio (10), the use of dairy fat blend was beneficial in terms of brain DHA accretion in young rats and a further increase of brain DHA was obtained by using pure dairy fat (LA 2%, ALA 0.8%, LA/ALA 2.3). Cow's milk presents naturally some similarities (lipid quality, cholesterol, globule structure...) with human breast milk and cannot be compared to pure vegetable blends. Utilization of dairy fat in infant formula should be reconsidered, as well as the absolute amount of polyunsaturated LA and ALA: at least a reduction of LA for IF as well as for lactating women to improve breast milk quality.