Eric L. Lien

Human milk fatty acid composition from nine countries varies most in DHA

Many published studies of breast milk FA composition are limited to populations from one or two countries. We aimed to examine the degree to which FA compositions vary across a number of diverse populations. Because diet and maternal adipose stores influence breast milk FA composition, differences in FA composition between groups most likely reflect habitual dietary differences. Approximately 50 breast milk samples (full breast expression) were collected from women in Australia, Canada, Chile, China, Japan, Mexico, Philippines, the United Kingdom, and the United States. The proportion of saturated FA was relatively constant among countries, with the exception of the Philippines, where levels of lauric and myristic acids were elevated (means greater than two times the mean of most other countries). Monounsaturated FA also varied little, with the exception of low levels of oleic acid in the Philippines and high levels of erucic acid in China. Although arachidonic acid (C20∶4n−6) levels were similar among all countries (means ranging from 0.36 wt% to 0.49 wt%), mean DHA (C22∶6n−3) levels ranged from 0.17 to 0.99 wt%, with the highest levels in Japanese milk and the lowest levels in Canadian and U.S. samples. The results of this study demonstrate that the proportion of saturated and monounsaturated FA are relatively constant across a large number of countries, whereas the level of some of the PUFA, especially DHA, are highly variable.

Major Carotenoids in Mature human Milk: Longitudinal and Diurnal Patterns

The present study was undertaken to quantitate the major carotenoids in human milk, monitoring their variance among fore, mid, and hind mature milk samples; during morning, midday, and evening, and among different weeks of lactation. Twenty-three mothers, 6 weeks to 16 weeks postpartum, participated in the study. n nReversed-phase high performance liquid chromatography (RP-HPLC) was used to identify and quantitate the major carotenoids found in human milk, including lutein/zeaxanthin, beta cryptoxanthin, lycopene, alpha carotene, and beta carotene. To determine the validity of analyzing carotenoids in frozen milk, freshly expressed and subsequently frozen milk samples were analyzed for four mothers. Freezing did not alter carotenoid concentrations. n nWide variations in carotenoid concentrations existed within and between the mothers. Major carotenoid totals ranged from 29 nM to 493 nM. Complete breast expressions at three periods within a day and at specified weekly intervals allowed the accurate determination of diurnal as well as longitudinal carotenoid concentrations. Diurnal evaluation of carotenoid concentrations suggested a peak at midday and highest longitudinal concentrations were at 10 to 12 weeks. Neither of these trends was statistically significant. The analysis of fore, mid, and hind milk carotenoid concentrations demonstrated that hind milk was significantly higher than fore or mid milk (P < 0.05).

Selenium supplementation of infant formula: uptake and retention of various forms of selenium in suckling rats

Formula-fed infants often have lower serum selenium levels than breast-fed infants. Although no deleterious effects have been correlated to this finding, supplementation of formula with selenium is considered. In this study, we investigated the uptake and retention by suckling rat pups of 75Se from selenite, selenate, and selenomethionine added to infant formula. The molecular distribution of 75Se in liver, kidney, intestine, and plasma was followed by gel-filtration chromatography on Superose 12. 75Se-uptake was most rapid from selenomethionine (70% at 1 hr), followed by selenate (51%) and selenite (29%). This difference was explained by a higher retention of 75Se in the stomach and small intestinal wall of pups given selenite supplement. Plasma distribution of 75Se as studied by gel filtration was also different, with a higher proportion of 75Se from selenomethionine being protein-bound than from selenite or selenate. Similarly, a larger proportion of 75Se from selenomethionine became protein-bound in the liver than from selenite or selenate. In conclusion, although whole body retention after 24–48 hr was similar, the metabolic fate of selenium varies considerably with the form of selenium added to formula. Further studies are needed to study the long-term consequences of selenium accumulated in different body compartments.

Variations in Concentrations of Lactoferrin in Human Milk: A Nine Country Survey

Lactoferrin (Lf), an 80-kD glycoprotein, is a major whey protein in human milk (HM). The structure of Lf is similar to that of transferrin and ovotransferrin. Lactoferrin binds iron tightly and releases it at a pH less than 3.0 (Lonnerdal & Iyer 1995), has anti-inflammatory and antibacterial properties (Goldman et al. 1990), and has antioxidant properties (Huang et al. 1999).

Human Milk Fatty Aaid ProfIles From Australia, canada, Japan, and the Philippines

Human milk (HM) fatty acids (FAs) are derived from both dietary sources and from mammary gland synthesis. Dietary sources of essential FAs, linoleic acid (LA) and α -linolenic acid (ALA)1, as well as some long chain polyunsaturated FAs, such as docosahexaenoic acid (DHA), are a reflection of maternal diet. Mammary gland synthesis of saturated FAs, particularly up to a chain length of 14 carbons, is the predominant source of these FAs.2 However, dietary considerations also enter into the HM levels of saturated FAs, since low fat, high carbohydrate diets lead to elevated HM levels of lauric acid. The present study evaluates HM FA profiles from four countries, with approximately 50 samples evaluated per site.