Human milk: maternal dietary lipids and infant development

Abstract

Human milk provides all the dietary essential fatty acids, linoleic acid (LA; 18:2n-6) and α-linolenic acid (18:3n-3), as well as their longer-chain more-unsaturated metabolites, including arachidonic acid (20:4n-6) and DHA (22:6n-3) to support the growth and development of the breast-fed infant. Human milk levels of LA have increased in Westernized nations from mean levels (g/100 g total fatty acids) of 6 to 12–16 over the last century, paralleling the increase in dietary intake of LA-rich vegetable oils. DHA levels (g/100 g total milk fatty acids) vary from <0·1 to >1% and are lowest in countries in which the intake of DHA from fish and other animal tissue lipids is low. The role of DHA in infant nutrition is of particular importance because DHA is accumulated specifically in the membrane lipids of the brain and retina, where it is important to visual and neural function. An important question is the extent to which many human diets that contain low amounts of n-3 fatty acids may compromise human development. The present paper reviews current knowledge on maternal diet and human milk fatty acids, the implications of maternal diet as the only source of essential fatty acids for infant development both before and after birth, and recent studies addressing the maternal intakes and milk DHA levels associated with risk of low infant neural system maturation.

Comparative Lipid Profiles of Milk Bank Breast Milk and Infant Formulas

“…However, since many dairy and meat products contain CLA [16], once the infant is weaned from infant formula, these known CLA-containing foods are common dietary components. A similar concern for the absence of 22:4 (n-6), an essential precursor to very long-chain (n-6) PUFAs needed for normal spermatogenesis and fertility [17], in any of the infant formulas may be forestalled in view of the presence of 20:4 (n-6), the precursor to 22:4 (n-6).A number of reports have shown that both 20:4 (n-6) and 22:6 (n-3) levels in human milk correlate positively with infant growth and development [18,19]. Our data indicate that the 20:4 (n-6) and 22:6 (n-3) mole % ranges for the human samples (0.22-0.59 and 0.054-0.29 respectively) are quite comparable to those found for the infant formulas (0.34-0.63 and 0.085-0.22 respectively).…”

Field and laboratory methods in human milk research

“…Micronutrients (e.g., minerals and vitamins), macronutrients (e.g., fatty acids), energy density (kcal/g), and volume have all been reported to vary, to some extent, among non-Western populations (Jelliffe and Jelliffe, 1978;Prentice and Prentice, 1995). Micronutrients and fatty acids may be wholly or partially derived from current maternal diets (Francois et al, 1998;Innis, 2007;Milligan, 2013;Stuetz et al, 2012;Yakes et al, 2011), although macronutrients appear moderately buffered from shortterm nutritional fluctuations because mothers can mobilize body reserves for milk synthesis during lactation (Prentice et al, 1981b;Villalpando and Del Prado, 1999). Unlike milk macronutrient composition, milk volume may be more sensitive to changes in maternal condition (Ettyang et al, 2005;Prentice et al, 1981b;Villalpando et al, 1992; but see also Pérez-Escamilla et al, 1995).…”

Feeding vegetable oils to lactating ewes modifies the fatty acid profile of suckling lambs

“…CLA (in particular cis-9, trans-11) in milk fat has been associated with anticarcinogenic effects, and is produced either as an intermediate during rumen biohydrogenation of linoleic acid (Harfoot and Hazlewood, 1997), or in the mammary gland by D9 desaturase from trans-11 C18:1 (vaccenic acid, VA; Mosley et al, 2006). n-3 PUFA have health-promoting effects (Boure, 2005;Innis, 2007). Increased commercial interest in adding value to milk and meat by increasing their nutritional qualities has stimulated research in nutritional manipulation of their FA profiles.…”