Uniformity of human milk

Abstract

Compositon of human milk was studied during the feed in six women, through-out the day in one woman on 3 consecutive days and in three women on 39 occasions during established lactation. The total lipid content varied in the course of suckling as well as diurnally in a regular and predictable manner, but the fatty acid composition of the lipid remained constant and was similar in the subjects examined. Fatty acid pattern of milk lipid of one woman supplementing her diet with unsaturated fats was studied. The changes in the milk lipid compostion, induced by the altered diet, are discussed in relation to the mechanism of milk fat synthesis. The described changes in milk composition are specific and may be physiologically significant. The composition of lipid in milk of mothers on adequate and balanced diet shows only limited fluctuations forming a species-specific pattern. The variations that occur in extreme dietary conditions (malnutrition, undernutrition, supplementation) are not random and can be predicted.

Mother's iron status, breastmilk iron and lactoferrin – are they related?

“…Iron content of human milk is highest in early transitional milk (0.97 mg/l) (Lauber and Reinhardt, 1979) but decrease steadily during lactation, reaching a level of approximately 0.35 mg/l at 1 month of lactation to 0.20 mg/l at 6 months (Lemons et al, 1982;Lonnerdal, 1984). The diurnal variation in iron content of breastmilk tend to parallel those reported for fat content with significantly lower mean values in the early morning feeding compared to late evening feeding (Hall, 1979;Fransson and Lonnerdal, 1980). No significant correlations were found between maternal age, parity or previous history of lactation and the iron content of milk at each stage of lactation (Celada et al, 1982).…”

“…Studies on lactating women of varying ethnic origins have shown that breastmilk iron is independent of their hemoglobin (Hb) and iron status (Loh and Sinnathuray, 1971). Breastmilk iron and lactoferrin levels are known to vary according to the type of milk, age of lactation and diurnal variation (Hall, 1979;Houghton et al, 1985). Considering the varying epidemiological factors and the high degree of malnutrition and anemia in the lactating mothers of developing countries, the need for such a study was felt.…”

Essential fatty acids in breast milk of atopic mothers: comparison with non-atopic mothers, and effect of borage oil supplementation

“…A ®rst explanation for the inconsistencies between these studies may be related to the timing of breast sampling. Although fat content in mature breast milk varies by the duration of breastfeeding and during the day (Harzer et al, 1983), and during a nursing (Jensen et al, 1992;Hall, 1979), the fatty acid composition of the lipid fraction remains fairly constant in these time aspects (Jensen et al, 1992;Hall, 1979;Lammi-Keefe et al, 1990). Therefore, we do not believe that differences between studies could be explained by differences in the timing of breast milk sampling.…”

Field and laboratory methods in human milk research

“…Long the purview of nutritionists and clinicians, investigations of milk composition are increasingly conducted by anthropologists and human biologists. These studies forgo the assumption that milk is passively transferred from mother to infants (Hall, 1979), instead reframing human milk as a dynamic evolutionary and cross-cultural phenomenon that links mothers and infants. The nuances of the direct physiological exchange-from potential developmental signaling to the life history trade-offs of mothers and infants-have considerable potential for understanding population and individual biological variability for a host of phenotypes.…”