PubMed Health⌕ Search

Biomedical subjects

B Lönnerdal

Publications and source records attributed to B Lönnerdal.

260 records · Page 15Linked to original sources
PubMed1976

A longitudinal study of the protein, nitrogen, and lactose contents of human milk from Swedish well-nourished mothers.

The contents of total nitrogen, nonprotein nitrogen, lactose, and individual milk proteins have been determined in human milk from well-nourished Swedish mothers. Breast milk samples from 50 mothers at different stages of lactation (up to 170 days) were collected. Furthermore, three mothers gave samples repeatedly throughout the whole lactation period. The protein content in mature milk was found to be 0.8 to 0.9% by amino acid analysis. The nitrogen content and the contents of the major human milk whey proteins, alpha-lactalbumin and lactoferrin, are very high for the first few days, then decrease rapidly and reach, thereafter, the more slowly declining level of mature milk. Nonprotein nitrogen and the nonspecific milk protein serum albumin are present in constant concentrations throughout lactation. The daily milk volumes were determined and found to be 500 to 600 ml in the very early part and 700 to 800 ml in the later part of the lactation period.

Female↗
PubMed1976

Breast milk composition in Ethiopian and Swedish mothers. II. Lactose, nitrogen, and protein contents.

Breast milk from underprivileged and privileged Ethiopian mothers was collected at different stages of lactation and analyzed for total nitrogen, nonprotein nitrogen, lactose, and individual milk proteins (lactoferrin, alpha-lactalbumin, serum albumin, IgG and IgM). These values and the milk volume of one meal were compared to corresponding results from well-nourished Swedish mothers. No significant differences between the levels of these constituents or the milk volumes were found between the two groups of Ethiopian mothers. When comparison was made between breast milk from these two Ethiopian groups and the Swedish group, the former two showed significantly higher values for the iron-binding protein lactoferrin.

Ethiopia↗
PubMedDate not supplied

An approach to assessing trace element bioavailability from milk in vitro. Extrinsic labeling and proteolytic degradation.

Both in vitro and in vivo, the use of a radioisotope can significantly enhance the sensitivity of methods for trace element studies. An essential prerequisite for this approach, however, is that the added (extrinsic) radiolabel equilibrates with the native (cold) element within all compartments of the diet. By using ultracentrifugation, ultrafiltration, and gel filtration chromatography, we have shown that the method is valid for zinc, copper, and manganese when using milks and formulas. For iron, however, extrinsic labeling does not necessarily yield results similar to the native distribution. We have used extrinsic labeling to follow the distribution of Zn, Cu, and Mn between high molecular weight compounds (proteins) and low molecular weight complexes in human and bovine milk after in vitro proteolysis. Peptic digestion at various pHs and pancreatic digestion for varying times were used to mimic digestion in the infant. After limited proteolysis, a large proportion of trace minerals in human milk was found in the low molecular weight fraction, whereas in cow's milk a large proportion was bound to incompletely digested casein. These findings may, at least in part, explain the higher bioavailability of trace elements from human milk compared to cow's milk.

Animals↗