A pilot study of the quality of human milk in a lower socio-economic group in Karachi, Pakistan

Comparison of the Macronutrient Content of Colostrum: Locals with Refugees

Background: Breast milk (BM) is considered the ideal and natural way of feeding for all infants. Although previous studies evaluated the factors influencing the content of BM, data concerning the effect of being a refugee on macronutrient contents of BM are rather inadequate. Therefore, we aimed to compare the macronutrient content of colostrum samples of Turkish and Syrian mothers. Materials and Methods: BM from lactating mothers who delivered term newborns was collected within the first 48 hours of lactation. Milk protein, fat, carbohydrate, and energy levels were measured by using a mid-infrared human milk analyzer. Demographic characteristics of the mothers and the infants were recorded. Results: Colostrum samples of 180 lactating mothers (Turkish: 96, Syrian: 84) were obtained. There were no significant differences between the groups in terms of body mass index of the mothers, mode of delivery, and infant gender. However, Syrian mothers gained less weight during pregnancy compared with Turkish mothers (p = 0.029). The median protein, fat, and energy levels of colostrum samples were found to be significantly higher in Turkish mothers than in Syrian mothers (p = 0.001, p = 0.017, p < 0.001, respectively). Cesarean delivery and being a Syrian refugee were independently associated with lower protein content of colostrum in logistic regression analysis. Conclusion: Lactating mothers who delivered their babies through vaginal route were found to be advantageous in terms of colostral protein content. Also, an association between being a refugee and lower protein content of colostrum was remarkable.

Protein intake adequacy among Nigerian infants, children, adolescents and women and protein quality of commonly consumed foods

Protein is important for growth, maintenance and protection of the body. Both adequacy of protein quantity and protein quality in the diet are important to guarantee obtaining all the essential amino acids. Protein-energy malnutrition is widely present in developing countries such as Nigeria and might result in stunting and wasting. Needs for protein differ depending on age and physiological status and are higher during growth, pregnancy and lactation. The present review assessed protein quantity and quality in diets of Nigerian infants, children, adolescents, and pregnant and lactating women. Literature reviews and calculations were performed to assess adequacy of Nigerian protein intake and to examine the Nigerian diet. The digestible indispensable amino acid score was used to calculate protein quality of nine Nigerian staple foods and of a mixture of foods. The Nigerian population had mostly adequate protein intake when compared with the most recent protein recommendations by the FAO (2013) and WHO/FAO/UNU (2007). An important exception was the protein intake of adolescent girls and pregnant and lactating women. Most of the assessed Nigerian plant-based staple foods were of low protein quality and predominantly lacked the amino acid lysine. The addition of animal-source foods can bridge the protein quality gap created by predominance of plant-based foods in the Nigerian diet. The methodology of this review can be applied to other low- and middle-income countries where diets are often plant-based and lack variety, which might influence protein intake adequacy.

Gender-specific desensitization of group I metabotropic glutamate receptors after maternal l-glutamate intake during lactation

In the present work we have studied the effect of maternal intake of l-Glutamate (l-Glu) (1 g/L) during lactation on group I mGluR transduction pathway in brain plasma membrane from 15 days-old neonates. Results obtained have shown that maternal l-glutamate intake did not significantly affect neither weights of pups nor negative geotaxis reflex, an index of neurobehavioral development, but increased l-Glu plasma level in both male and female neonates. In male neonates, maternal l-Glu intake evoked a loss of mGluR₁ whereas no variation on mGluR₅ was observed as revealed by Western-blotting assay. The loss of mGlu₁R was accompanied by a decrease on l-Glu-stimulated phospholipase C activity suggesting, therefore, a loss of group I mGluR functionality. Concerning female neonates, no variations were detected neither mGluR₁ nor mGluR₅ and group I mGluR functionality was also preserved.

Amino acid profiles in term and preterm human milk through lactation: a systematic review

Amino acid profile is a key aspect of human milk (HM) protein quality. We report a systematic review of total amino acid (TAA) and free amino acid (FAA) profiles, in term and preterm HM derived from 13 and 19 countries, respectively. Of the 83 studies that were critically reviewed, 26 studies with 3774 subjects were summarized for TAA profiles, while 22 studies with 4747 subjects were reviewed for FAA. Effects of gestational age, lactation stage, and geographical region were analyzed by Analysis of Variance. Data on total nitrogen (TN) and TAA composition revealed general inter-study consistency, whereas FAA concentrations varied among studies. TN and all TAA declined in the first two months of lactation and then remained relatively unchanged. In contrast, the FAA glutamic acid and glutamine increased, peaked around three to six months, and then declined. Some significant differences were observed for TAA and FAA, based on gestational age and region. Most regional TAA and FAA data were derived from Asia and Europe, while information from Africa was scant. This systematic review represents a useful evaluation of the amino acid composition of human milk, which is valuable for the assessment of protein quality of breast milk substitutes.

Amino acid intake during lactation and amino acids of plasma and human milk

The aim of this study was to determine the free amino acid pool in plasma and milk in marginally nourished lactating women. Twenty-eight rural women (age, 23.9+/-5y; weight 50.2+/-4.9 kg; height, 148.2+/-4.8 cm) were studied under metabolic balance conditions. Subjects were divided into 6 groups (5-6 women in each), representing rural mothers postweaning and in the 15, 3rd, and 6th months of lactation; nonpregnant, nonlactating controls were from rural and urban areas. Amino acid analyses of diet and of plasma and milk samples were performed using a Beckman 6300 amino acid analyzer. Lysine intakes were lower than the recommended intake for lactating women (RDA). Plasma amino acid profiles differed between the lactating and weaned groups: aspartate and isoleucine increased at the 6th month (P < 0.05), while valine declined over weaning time (P < 0.05). In milk, valine and proline decreased at the 6th month (P < 0.05), while serine rose at the 3rd month. Free amino acid pools were 1- to 15-fold higher in plasma than in milk for branched-chain amino acids and basic, aromatic, and neutral amino acids. In mammary tissue these amino acids can be channeled to tissue and milk protein synthesis or to catabolic pathways. Glutamate was 40-fold higher in milk with respect to plasma content. This was the predominant amino acid in the free amino acid pool in milk. These results suggest selective amino acid transport in mammary tissue during lactation.

Regulation of mineral and trace elements in human milk: exogenous and endogenous factors

Breast-fed infants are dependent on an adequate supply of minerals and trace elements for normal growth and development. For most of these elements, the mammary gland appears to have developed mechanisms to regulate their concentrations, even when the maternal diet varies considerably or maternal conditions are affected by different challenges. For some elements, however, there appears to be little or no such regulation. Increased knowledge about these mechanisms, or their absence, and to what extent they may compensate for adverse maternal conditions, including poor nutrition, will help identify infants and women at risk for deficiencies of these nutrients.

Marginal dietary protein restriction reduced nonprotein nitrogen, but not protein nitrogen, components of human milk

OBJECTIVE

This study was designed to determine whether marginal dietary protein intakes of lactating women alter their milk production and composition. The study followed the observation that marginal dietary protein intakes lead to significantly negative nitrogen balances in these women.

METHODS

Twenty-four healthy, mature lactating women were divided evenly into three groups on the basis of postpartum times; 1, 5, or 12 months. Each woman was given a controlled protein diet of either 1.5 (HP) or 1.0 (MP) g/kg body weight/day for 7 to 10 days. Milk production was measured for 72 hours by test weighing the infant before and after feeding. Milk samples from alternate breasts were collected for 24 hours, pooled, and analyzed for their protein nitrogen, nonprotein nitrogen, free and protein-bound amino acid, and lactoferrin concentrations.

RESULTS

Reduced dietary protein intakes were associated with a decrease (p < 0.05) in the nonprotein nitrogen and total free amino acid fractions of milk. Although urea was unaffected, the concentrations of milk free leucine, phenylalanine, histidine, and ornithine were lower (p < 0.05) in the MP than in the HP group, while the output of leucine and histidine tended to be lower in the MP group. The amount of milk produced, as well as the amounts of protein nitrogen, protein-bound amino acid, and lactoferrin and their concentrations were unaffected by a reduction of dietary protein.

CONCLUSIONS

Maternal milk production and the protein nitrogen, but not the nonprotein nitrogen, fraction of human milk were relatively well-preserved in the presence of a short-term, marginal reduction of dietary protein.

Mother's milk and pseudoscientific breastmilk testing in Pakistan

In urban squatter settlements and rural villages of Pakistan, human breastmilk is regarded as a potential source of destruction as well as of nurturance. Though it is highly valued as crucial for infant survival, it is also thought susceptible to becoming tainted in many ways: by a 'shadow' from the spirit world; by 'evil eye' or black magic due to others' envy; by the effects of a new pregnancy; by the mother's illness or 'weakness'; by her exposure to excessive cold or heat; by her dietary indiscretions. In any of these circumstances, women may stop breastfeeding to prevent illness in the nursing child. Sometimes the stoppage is temporary, brief, and has no serious consequences. When the mother is pregnant, however, it is permanent. Further, if a child is sickly, cries a great deal, has prolonged diarrhea, or seems reluctant to suck, mothers frequently become alarmed and suspect irreversible breastmilk 'poisoning'. In the latter case, a folk healer has traditionally been consulted to test the milk's quality, but in recent years pathology laboratories have increasingly taken on this function in all of the major cities in Pakistan. Not only does the mother stop breastfeeding while the milk is being tested, but often she is unable or unwilling to resume nursing even if the milk is eventually pronounced safe to drink. This manifestation of inappropriate, child-endangering technology has gained acceptance partly because of maternal anxieties heightened by commercially-driven pressures to be 'modern' and partly because of its congruence with traditional ideas surrounding breastmilk, many of which have classical antecedents.

Fat and protein composition of mature milk in adolescents

The levels of certain components, notably total protein, total fat, energy, and fatty acids, of mature milk from 48 adolescent and 44 adult mothers was studied. These two groups were subdivided into high and low socioeconomic level (SEL). All mothers were primiparous, eutrophic, and with term pregnancy; and their newborns weighted over 2500 g at birth. The age factor appeared to have significant influence on the concentration of total protein, with higher levels in the group of adolescent mothers possibly as a compensatory mechanism to maintain the caloric value of the milk. The fatty acid content was altered significantly by the SEL probably due to the direct effect of maternal diet. The milk in adolescent mothers of low SEL demonstrated higher concentration of lauric and myristic acids, while the milk in low SEL adults contained higher proportions of linoleic and linolenic acids. The milk in adult mothers of high SEL demonstrated higher concentrations of palmitic, palmitoleic, and oleic acids. The different feeding habits of two socioeconomic groups may explain these results. The regular intake of soya oil, corn oil, and margarine by the urban population in general resulted in higher levels of linoleic acid in the milk of all groups studied.

Amino acid levels in the critically ill preterm infant given mother's milk fortified with protein from human or cow's milk

Twenty preterm infants undergoing neonatal intensive care were randomly allocated to one of two feeding regimens: human milk enriched with either human milk protein (HMP) or adapted cow's milk protein (CMP). The birthweights (1076 +/- 301 g; 1031 +/- 309 g) and the gestational ages (28.4 +/- 1.6 weeks; 27.7 +/- 2.1 weeks) were comparable. The amount of protein added to the milk was set at 0.7 g/100 ml in order to provide a total supply of 3.0-3.5 g/kg/24 h. All infants received additional amounts of carbohydrate, calcium, phosphorous, and sodium chloride. Capillary whole blood amino acids were measured with high pressure liquid chromatography (HPLC). The amino acid levels did not differ significantly when the feeding groups were compared week by week, but the glycine/valine ratio was higher (p less than 0.05) in the HMP group after three weeks of fortification. Longitudinal changes after protein enrichment could be demonstrated in both groups. Alanine and threonine increased after one week (p less than 0.01) in both groups. Glycine in the HMP group peaked after two weeks (p less than 0.02), and valine in the CMP group increased (p less than 0.02) after one week on the feeding regimen. However, the amino acids never reached levels above those seen after a meal in normal term newborns. Other variables related to protein intake, such as protein and urea in serum, did not vary between the groups. Growth, expressed as gains in weight, length, and head circumference was poor but comparable. The quality of the protein, whether a human milk protein isolate or a cow's milk whey protein product, used for the fortification of human milk up to a protein load of 3.0-3.5 g/kg/24 h, did not cause any alterations of significance in the amino acid profiles of peripheral blood.

The state of food production and nutrition in the developing countries

The genesis of the problem of food production and nutrition of African, Asian and Central and South American countries can be traced back to the beginning of 'inter-continental trade' and the emergence of colonialism. Indigenous food patterns and social and economic orders that had evolved to befit the inhabitants and the environment were destroyed. A nutritional framework and an agricultural and economic policy designed to benefit the colonising nations were fostered. At present, millions of people in the developing countries suffer from endemic undernutrition and associated diseases. Famine is always present under the surface claiming families and individual hamlets and breaks through when the semblance of equilibrium between minimal food requirement for survival and supply is disturbed by natural or man-made disaster. Landlessness, an uneven distribution of wealth, overemphasis on cash-crop production, neglect of peasant agriculture in favour of unnecessary expenditure on military hardware and other misguided projects, and crop specialisation are some of the factors responsible for food shortage and undernutrition. Moreover, most of the staple foods of the developing countries are of low energy density and deficient in some essential nutrients. The cycle of undernutrition, hunger, disease and death can only be broken by instituting a well planned, peasant-orientated, integrated development programme based on self-reliance and self-sufficiency.

Quantities of amino acids ingested by human milk-fed infants

The purpose of this investigation was to provide quantitative data on amino acids ingested by human milk-fed infants. Ten term infants fed human milk ad libitum were studied at 2, 4, and 8 weeks of age. Measurements of milk volume and amino acid analyses of milk samples were performed. Both total amino acid and nitrogen intakes (mumole/kg/day) declined by approximately 34% during the study (P less than 0.001) to 0.05), primarily because of a 20% decline in respective concentrations in human milk (P less than 0.001). Consequently, markedly different amino acid intakes were observed at 2 and 8 weeks. Quantities of amino acids consumed by nearly every infant exceeded estimated Food and Agriculture Organization/World Health Organization requirements at 2 weeks. However, mean intakes for seven of nine essential amino acids studied (phenylalanine, tyrosine, methionine, threonine, valine, leucine, and lysine) were less than recommended quantities at 8 weeks. These same relationships between observed and recommended intakes were also evident at 4 weeks, except for lysine and leucine. Mean intakes of histidine and isoleucine exceeded estimated requirements at all times. These data indicate that FAO/WHO estimates of amino acid requirements may be inflated for phenylalanine, tyrosine, methionine, threonine, valine, leucine, and lysine.

Fat and energy content of breast milk of malnourished and well nourished women, Brazil 1982

An investigation of the fat content of breast milk was carried out in 71 Brazilian women from a poor socio-economic background and in 10 from a high social class. All were breastfeeding their infants without supplements. Of the 81 women, 28 "poor" women were assessed as "malnourished" according to weight-for-height criteria, and varying proportions as "malnourished" when other criteria were used. The milk of "malnourished" mothers, even when malnutrition was severe, was slightly (but not statistically significantly) richer in fat than that of well-nourished women. The proportion of primiparous women was similar in both nutritional groups, and multiparity up to five pregnancies was associated with an increased fat concentration. Infants from all groups gained weight in a similar "normal" way, demonstrating that poor maternal nutritional status in this population had no adverse effect on the adequacy of lactation. It was concluded that the promotion of exclusive breastfeeding for at least 4 months was a realistic objective of the Brazilian National Breastfeeding Programme.

Plasma valine and urinary C-peptide in breast-fed and artificially fed infants up to 6 months of age

Plasma branched-chain amino acids and urinary C-peptide-creatinine excretion was determined at 3, 4 1/2 and 6 months of age in a group of 50 infants who were either breast-fed or artificially fed and selected at random. The average concentrations of valine in plasma and C-peptide in urine as well as the ratio between C-peptide and creatinine in urine were 2-3 times higher (p less than 0.01) in artificially fed as compared to breast-fed infants at all the ages studied. Plasma valine values correlated significantly with the urinary C-peptide/creatinine ratio (r = 0.76, p less than 0.01), which suggests that the enhanced insulin response induced by the artificial formula is related to its protein content.

Breast milk in Botswana: cream and vitamin C contents

Breast milk samples taken at the end of suckling from 112 Botswanan and 17 British mothers were analysed for cream and vitamin C content. Cream was estimated using the creamatocrit method. Measurements of triceps skinfold thickness and mid upper arm circumference were similar in the two groups. The mean (s.d.) vitamin D content of milk in Botswana was 84.60 mumol/l (73.81) [1.49 mg/dl (1.30)] which was less than the mean of 269.70 mumol/l (109.58) [4.75 mg/dl (1.93)] (P less than 0.0001) in Britain, especially among grand multiparae. The Botswanan mean (s.d.) creamatocrit of of 5.32% (2.48%) was lower than that of the British, 7.93% (2.81%) (P less than 0.01). Possible explanations are discussed.

Breastfeeding in developing countries

The calculated protein and calorie requirements and nutritional status of intrauterine-growth-retarded infants of poor mothers in underdeveloped countries were compared with the estimated amounts of protein and calories supplied in the mother's milk and their nutritional status both before and during lactation. These mothers were only able to provide 69% of the infants' protein requirements at birth, falling to 51% at three months of age 123% of calorie requirements were supplied at birth, falling to 55% at three months. Conversely, in terms of g protein per 100 kcal, 56% of requirements were met at birth, rising to 95% at three months-figures which reflect the decreasing protein requirement with age. Socioeconomic factors determine nutritional status in developing countries and it is the responsibility of governments to ensure the health and adequate nutrition of mothers and infants.

Drug excretion in human breast milk: principles, pharmacokinetics and projected consequences

The excretion of drugs in human breast milk is reviewed with regard to milk production, composition, feeding patterns and mechanisms of drug transfer into milk. Fundamental principles of breast milk excretion are used to construct a pharmacokinetic approach useful for the study of most drugs. An infant-modulated 3-compartment open model is proposed for drug distribution and elimination in the breast feeding woman. Milk/plasma drug concentration ratios are projected on the basis of pH partitioning. While some studies confirm these projections, other studies demonstrate a need to consider additional factors such as lipid solubility and protein binding characteristics of a drug in milk. Data are lacking for most drugs and hence dosing via milk or risk to the infant remains speculative. Very few pharmacokinetic studies of both milk and infant plasma were found. A review of selected drug classes cites available information as a basis for future studies. Few drugs are contraindicated in breast feeding women, but supportive data for either proscriptions or permissive statements are often lacking. A neglected but potentially serious infant risk--impaired behaviour and development--is discussed from the standpoint of emerging animal data. Conceptually valid and comprehensive studies on drug excretion in breast milk are needed if this valuable nutrient for infants is to be made available safely.

Free amino acid, protein, and fat contents of breast milk from Guatemalan mothers consuming a corn-based diet

Diet compositions and breast milk levels of free amino acids, protein, and lipid were compared in lactating American and Guatemalan women. The protein in the American diet derived principally from animal sources, whereas that in the Guatemalan diet was based most exclusively on cereal grains and legumes. Corn, in the form of cornmeal, was the predominant food. Because of these dietary differences, the Guatemalan women consumed significantly smaller amounts of protein than the American women. The concentrations of most of the free amino acids in aliquots of breast milk from the Guatemalan women were lower than those in samples from the American women. In particular, tryptophan and lysine levels were 23% and 29%, respectively, of the levels in the American breast milk samples. The Guatemalan samples contained less protein, and, when values from Guatemalan women who had nursed only for 6 mth or less were considered, the fat content was also less than in the American samples. The lipid content of the milk, however, did not differ between the two groups when the length of the lactation period was not controlled. The substantial cultural differences between the two groups in the frequency and duration of nursing probably prevented the identification of a clear dietary influence on milk lipid content. The correlations found between diet composition and either the amount of protein or the levels of free amino acids in breast milk suggest that, if a mother's diet is deficient in high-quality protein, the deficiency may be reflected in the composition of her milk, perhaps to the detriment of the nursing infant.

Plasma free amino acid concentrations of breast-fed infants

Photometric determination of alpha-amino nitrogen in peripheral venous plasma and urine from 20 healthy, full-term infants, 1--5 months of age, showing normal growth and development during an uncomplicated lactation, revealed lower plasma levels than what has been found in adults, or 3.7 +/- 1.1 mg/100 ml, and a urinary excretion of 41 +/- 14 mg/24 hours. Ion-exchange chromatography of deproteinized peripheral venous plasma showed low valine concentrations, an increased glycine/valine ratio and high cystine and very high taurine levels when compared to the levels of healthy American infants of comparable ages fed 3--3.5 g/kg of cow-milk protein. The findings indicate that a formula based on cow-milk protein should optimally contain only 1.0--1.2 g protein/100 ml provided that it is "humanized" not only with regard to the lactalbumin/casein ratio, but also to the cystine and taurine content. The pattern of the plasma concentrations of free amino acids reported in the present investigation may be used as a normal reference for breast-fed infants.

Escherichia coli O antibody content in milk from healthy Swedish mothers and mothers from a very low socio-economic group of a developing country

The antibody content of milk from healthy Swedish mothers was compared with that of milk from mothers of a very low socio-economic group in a developing country. Antibodies of various immunoglobulin classes against E. coli O antigens were determined with the enzyme-linked immunosorbent assay (ELISA). The milk antibodies which mainly belonged to the secretory IgA class appeared in similar concentrations in milk from the two groups using E. coli antigens of Swedish as well as Pakistani origin. The secretory IgA antibodies could be demonstrated in the stool of the breast-fed infants of the undernourished mothers. Also the concentration of serum IgG and IgA antibodies to E. coli O antigens were similar in the Pakistani and Swedish mothers. The serum IgM antibody levels of the Pakistani mothers were higher, however, presumably due to a higher frequency of infections. It was noted that the milk production decreased considerably upon the hospitalization of the healthy and well-to-do Swedish mothers. The small milk volumes of the undernourished Pakistani mothers suggest that the lactation failure observed was mainly due to inadequate milk flow and not to decreased milk quality. The results indicate the necessity of studying the nutritional, psychological and social factors responsible for low milk yield and add yet another reason to stimulate prolonged breastfeeding.