Comparison of macronutrient contents in human milk measured using mid‐infrared human milk analyser in a field study vs. chemical reference methods

Macronutrient contents in human milk are the common basis for estimating these nutrient requirements for both infants and lactating women. A mid‐infrared human milk analyser (HMA, Miris, Sweden) was recently developed for determining macronutrient levels. The purpose of the study is to compare the accuracy and precision of HMA method with fresh milk samples in the field studies with chemical methods with frozen samples in the lab. Full breast milk was collected using electric pumps and fresh milk was analyzed in the field studies using HMA. All human milk samples were thawed and analyzed with chemical reference methods in the lab. The protein, fat and total solid levels were significantly correlated between the two methods and the correlation coefficient was 0.88, 0.93 and 0.78, respectively (p < 0.001). The mean protein content was significantly lower and the mean fat level was significantly greater when measured using HMA method (1.0 g 100 mL^?1 vs 1.2 g 100 mL^?1and 3. 7 g 100 mL^?1 vs 3.2 g 100 mL^?1, respectively, p < 0.001). Thus, linear recalibration could be used to improve mean estimation for both protein and fat. There was no significant correlation for lactose between the two methods (p > 0.05). There was no statistically significant difference in the mean total solid concentration (12.2 g 100 mL^?1vs 12.3 g 100 mL^?1, p > 0.05). Overall, HMA might be used to analyze macronutrients in fresh human milk with acceptable accuracy and precision after recalibrating fat and protein levels of field samples.     

Macronutrient and energy contents of human milk fractions during the first six months of lactation

Aim: To study the macronutrient and energy contents of human milk fractions during the first 6 mo of lactation. Study design: A total of 483 milk samples, including 52 pairs of fore- and hindmilk samples from 20 mothers, 253 samples from 53 donor mothers and 126 samples from 36 mothers of preterm infants, were collected longitudinally, starting at 1 wk postpartum and continuing monthly up to 6 mo. Protein, lactose and fat contents were measured and energy density estimated. Results: The protein content was significantly lower in fore- and hindmilk than in donor or preterm milk during the first months of lactation. In donor and preterm milk, the protein content declined consistently from 2.0 g/100 ml at 1 wk to half of that at 6 mo, and a similar trend was observed in fore- and hindmilk. Lactose content showed no significant changes between the groups or in the course of lactation. The fat content was highest in hindmilk, being approximately two- to threefold that of foremilk. Accordingly, hindmilk included 25-35 kcal/100 ml more energy on average than foremilk.

Conclusions: The fat content of human milk increases in relation to breast emptying, while the other macronutritients of milk show only slight changes. When enteral feeding with high-energy human milk is preferred, as in the case of very preterm infants, hind milk, with its higher fat content, would be a natural choice.     

Freezing and thawing effects on fat,protein, and lactose levels of human natural milk administered by gavage and continuous infusion

Objectivesto analyze the changes in human milk macronutrients: fat, protein, and lactose in natural human milk (raw), frozen and thawed, after administration simulation by gavage and continuous infusion.Methodan experimental study was performed with 34 human milk samples. The infrared spectrophotometry using the infrared analysis equipment MilkoScan Minor® (Foss, Denmark) equipment was used to analyze the macronutrients in human milk during the study phases. The analyses were performed in natural (raw) samples and after freezing and fast thawing following two steps: gavage and continuous infusion. The non-parametric Wilcoxon test for paired samples was used for the statistical analysis.Resultsthe fat content was significantly reduced after administration by continuous infusion (p < 0.001) during administration of both raw and thawed samples. No changes in protein and lactose content were observed between the two forms of infusion. However, the thawing process significantly increased the levels of lactose and milk protein.Conclusionthe route of administration by continuous infusion showed the greatest influence on fat loss among all the processes required for human milk administration.     

Comparison of macronutrient concentration of preterm human milk between two milk expression techniques and two techniques for quantitation of energy

Generally, when newborns in intensive care units receive human milk, we do not know the quantity of nutrients in that milk because such analysis is time-consuming and expensive. In our study, however, we sought to compare fat, protein, lactose, and energy concentration of a three-times-a-day sampling with a 24-h expression and to measure the difference between the calculated energy yield from protein, fat, and carbohydrate measurements and bomb calorimetry. At 14-18 days postpartum, 20 mothers of premature infants (30-34 weeks' gestation) expressed milk three times a day: 8 a.m., 12 p.m., and 8 p.m. At these three times, each mother expressed 3-5 ml of fore-milk and 3-5 ml of hind-milk for the sampling; the result was pooled for a 24-h expression. Only fat concentration differed significantly between fore- and hind-milk samples. Protein, fat, lactose, and energy concentration did not differ significantly between the two collection methods, 24-h expression and sampling. Moreover, we found no significant difference between the calculated number for energy content and the bomb calorimetry method of energy determination. The average fore- and hind-milk samples at 12 p.m. matched the 24-h milk expression. For clinical use, a milk sample obtained around 12 p.m. can predict macronutrient concentration, therefore allowing us to calculate an infant's approximate nutrient consumption.     

Comparison of mid‐infrared transmission spectroscopy with biochemical methods for the determination of macronutrients in human milk

The variability of human milk (HM) composition renders analysis of its components essential for optimal nutrition of preterm fed either with donor's or own mother's milk. To fulfil this requirement, various analytical instruments have been subjected to scientific and clinical evaluation. The objective of this study was to evaluate the suitability of a rapid method for the analysis of macronutrients in HM as compared with the analytical methods applied by cow's milk industry. Mature milk from 39 donors was analysed using an infrared human milk analyser (HMA) and compared with biochemical reference laboratory methods. The statistical analysis was based on the use of paired data tests. The use of an infrared HMA for the analysis of lipids, proteins and lactose in HM proved satisfactory as regards the rapidity, simplicity and the required sample volume. The instrument afforded good linearity and precision in application to all three nutrients. However, accuracy was not acceptable when compared with the reference methods, with overestimation of the lipid content and underestimation of the amount of proteins and lactose contents. The use of mid‐infrared HMA might become the standard for rapid analysis of HM once standardisation and rigorous and systematic calibration is provided.     

Establishment of micromethods for macronutrient contents analysis in breast milk

Commercially available milk analysers were originally developed for use in the dairy industry, but they are now used to analyse macronutrient content of breast milk in clinical studies and routine care of the premature or very low birthweight (VLBW) infants. Due to the different composition of cow and breast milk, these devices need to be validated against reference methods before they can be used in daily routine. However, current reference methods require a sample volume of 30–100 mL to analyse fat, protein and lactose. It is not feasible to obtain this volume of milk for research purposes, especially from VLBW infants as lactation may be delayed or impaired and the limited volume of breast milk must be provided to the infant. To support validation of milk analysers in both clinical and research settings, the aim of this study is to establish and validate micromethods for precise macronutrient analysis in small volume of breast milk and conduct a feasibility study of the micromethods as a post‐validation. Methods include a modified Mojonnier ether extraction (fat), elemental analysis (protein) and ultra‐performance liquid chromatography‐tandem mass spectrometry (lactose). We were able to downsize volumes required for analysis of fat, protein and lactose to 1 mL, 260 μL and 100 μL; corresponding coefficients of variation are 1.7, 1.8 and 2.3%, respectively. The presented methods allow for reliable and precise analyses of macronutrients in ≤1.5 mL of breast milk and will be used to validate milk analysers.     

Creamatocrit, carbon content, and energy value of pooled banked human milk: implications for feeding preterm infants

It is convenient to calculate milk energy from the creamatocrit but in order to assess the accuracy with which energy content can be predicted in this way, the creamatocrit, the percentage of carbon, and the calorie value of milk were determined in 11 samples of pooled pasteurised human milk. The calculated milk energy was compared with direct measurements of milk energy by static bomb calorimetry. The errors in calculation ranged from -5.6 kcal/100 ml to + 19.5 kcal/100 ml in milk samples whose measured energy was 34.5 to 63.1 kcal/100 ml. In 9 milk samples energy values were over-estimated by calculation and in the remaining 2 milk samples energy values were underestimated. The correlation between creamatocrit and measured energy value in pooled pasteurised milk was weaker than in previous studies using fresh milk. The percentage carbon was determined in our milk samples as a measure of their total organic constituents, and this appeared to be a more accurate predictor of milk energy than the predictive value of the creamatocrit which is only a measure of milk fat. In pooled pasteurised milk the relatively weak predictive value of the creamatocrit may be due to variations in the other constituents of milk apart from fat which provide energy, namely protein and lactose.     

Breast milk from mothers of very low birthweight infants: variability in fat and protein content

While breast milk appears to be superior to formula for the development of very low birthweight (VLBW) infants, it is supplemented to meet the metabolic demands of the rapidly growing premature infant. To estimate the nutritional variability of breast milk from mothers of VLBW infants, protein (bicinchoninic acid method) and fat content (creamatocrit) were measured in breast-milk spot samples from mothers of 20 VLBW infants, collected 4 times a day during the first 4 wk of lactation. Protein content (median 1.9 g dl(-1), range 1.1-3.5 g dl(-1)) and fat content (3.8/1.0-14.6 g dl(-1)) were highly variable and lacked a normal distribution over all samples and in individual women's milk. There was only a weak correlation between fat and protein (rs=0.416, p < 0.001). Fat but not protein was lower in morning samples than in samples collected later in the day (p < 0.001). Protein but not fat content decreased during the weeks of lactation (rs =-0.446, p < 0.001). No impact of the baby's gestational age was observed. CONCLUSION: The fat and protein content of breast milk from mothers of VLBW infants is highly variable, calling into question the clinical feasibility of individualized supplementation of breast milk for VLBW infants based on spot sample measurements.     

Infrared analysis for determining macronutrients in human milk

Infrared (IR) analysis is widely used for routine analysis of cow milk in dairies. The aim of this study was to evaluate the precision and accuracy of an IR analyzer (Milko-scan 104) for measuring protein, fat, carbohydrate, and, indirectly, the energy content of human milk. The results of the IR analysis were compared with those of the following reference methods: protein--Kjeldahl (nitrogen minus nonprotein nitrogen); fat--Roese Gottlieb; carbohydrate--lactose enzymatic assay; energy--bomb calorimetry. The precision (repeatability coefficient of variation) of the IR results was high for all four components: protein 0.4%, fat 1.0%, carbohydrate 0.2%, and energy 0.1%. There was a close linear covariation between IR results and reference results. [Protein content was determined with an error (SD) of 0.01 g/100 ml and fat with an error of 0.03 g/100 ml.] The covariation between IR carbohydrate results and the results of the lactose assay was poor, probably because the oligosaccharides in the milk were included in the results from the IR analysis and not in the results from the lactose assay. IR analysis is a valuable method in research, especially in epidemiological surveys, in which large numbers of samples are analyzed, and for continuous monitoring of the nutritional value of human milk in milk banking programs.     

Macronutrient and energy content of breast milk of mothers delivering prematurely

The protein, lactose, fat and energy contents of the fore-milk of mother with term (n=23) and preterm (n=29) infants were estimated on postpartum days 3, 7, 14 and 21. During the first 4 weeks of lactation, the mean (±SD) energy (Kcal/dl), protein (g/dl), fat (g/dl) and lactose (g/dl) levels of the preterm milk were: 56.39 (±7.99), 2.17 (±0.66), 2.30 (±0.48) and 5.78 (±0.99), respectively. The same for term milk were: 59.39 (±8.30), 1.99 (±0.70), 2.48 (±0.53) and 6.24 (±1.08), respectively. The differences in composition between the term and preterm milk were not significant. The composition of breast milk showed changes over the first 3 weeks of lactation. With increasing post-partum days, there was a decline in protein content while fat, lactose and energy contents increased. These trends were more pronounced for preterm milk than term milk. The macronutrient composition and energy estimates of preterm breast milk of Indian mothers in this study may be useful for calculation of nutritional intake by premature neonates fed on expressed breast milk.     

Acute changes to breast milk composition following consumption of high‐fat and high‐sugar meals

Breast milk composition is influenced by habitual diet, yet little is known about the short‐term effects of changes in maternal diet on breast milk macronutrient concentrations. Our aim was to determine the acute effect of increased consumption of sugar/fat on breast milk protein, lactose and lipids. Exclusively breastfeeding women (n = 9) were provided with a control, higher fat (+28 g fat) and higher sugar (+66 g sugar) diet over three separate days at least 1 week apart. Hourly breast milk samples were collected concurrently for the analysis of triglycerides, cholesterol, protein, and lactose concentrations. Breast milk triglycerides increased significantly following both the higher fat and sugar diet with a greater response to the higher sugar compared to control diet (mean differences of 3.05 g/dL ± 0.39 and 13.8 g/dL ± 0.39 in higher fat and sugar diets, respectively [P < 0.001]). Breast milk cholesterol concentrations increased most in response to the higher sugar diet (0.07 g/dL ± 0.005) compared to the control (0.04 g/dL) and the higher fat diet (0.05 g/dL) P < 0.005. Breast milk triglyceride and lactose concentrations increased (P < 0.001, P = 0.006), whereas protein decreased (p = 0.05) in response to the higher fat diet compared to the control. Independent of diet, there were significant variations in breast milk composition over the day; triglycerides and cholesterol concentrations were higher at end of day (P < 0.001), whereas protein and lactose concentrations peaked at Hour 10 (of 12) (P < 0.001). In conclusion, controlled short‐term feeding to increase daily sugar/fat consumption altered breast milk triglycerides, cholesterol, protein and lactose. The variations observed in breast milk protein and lactose across the 12 h period is suggestive of a circadian rhythm.     

Intérêt de la supplémentation du lait maternel « à la carte «

Despite the benefits of human milk fortification, nutrients of human milk are not sufficient to cover the greater needs of very low birth weight and to ensure a growth similar to that of premature infants fed with preterm formula. These differences could be related to the variation in the macronutrient composition of expressed breast milk with lower protein and energy content. Unfortunately there is unusually no information on macronutrients composition prior human milk fortification. With such data, it would be possible to individualize the fortification. In order to use adjustable fortification of human milk, we have assessed a rapid and simple method using full spectrum infrared laser technology (Milkoscan®) to analyze human milk composition. We describe the variation in concentration of protein, lipid and energy in the human milk received in our neonatal unit. Then we evaluate the benefit of adjustable fortification of human milk compared with standard fortification. After standard fortification the variability of protein and lipid remains with a risk of protein deficiency or excess and a risk of energy deficiency. After adjustable human milk fortification based on human milk analysis using Milkoscan®, we observe a more stable protein content and a lower amount of added fortifier decreasing the risk of hyperosmolarity. Furthermore, the energy content is higher following of the fat human milk adjusted content. Up to now, our preliminary results suggest that individualized fortification of human milk improves growth rate in preterm infants (21 g/kg/d) to a level close to formula fed infants.     

Composition of milk obtained from unmassaged versus massaged breasts of lactating mothers

BACKGROUND: The Oketani method is a program of breast massage and clinical counseling developed by the midwife Satomi Oketani. The purpose of this study is to examine the effects of the method on the quality of breast milk by determining the chemical composition of the milk before and after massage. METHODS: Milk samples were obtained immediately before and after massage from healthy, exclusively breast-feeding Japanese mothers at two different periods of lactation one <3 months the other >3 months after parturition. Lipids, whey protein, casein, lactose, ash, and total solids in milk were measured in milk samples. The gross energy content of milk was estimated. RESULTS: Breast massage significantly increased lipids in the late lactating period but not in the early lactating period. In the early lactating period casein was increased by breast massage but was not significantly affected in the late lactating period. Breast massage caused a significant increase in total solids from the first day to 11 months post partum. The gross energy in the late lactating period was significantly increased by breast massage but not in the early lactating period. Lactose was not significantly changed by breast massage. CONCLUSIONS: Breast massage improves the quality of human milk by significantly increasing total solids, lipids, and casein concentration and gross energy. The milk of mothers treated by Oketani breast massage may improve the growth and development of infants.     

LACTOSE AND PROTEIN ABSORPTION FROM BREAST MILK AND COW'S MILK PREPARATIONS AND ITS INFLUENCE ON THE INTESTINAL FLORA Investigations on two Infants with an Artificial Anus

Abstract. Lactose and protein absorption from breast milk and a cow's milk preparation enriched up to 7% of lactose were studied in two infants with an artificial anus applied in the ascending colon region. The concentrations of protein, lactose, glucose and galactose were measured in the fistula stools. In addition, the stools were analysed microbiologically. There were relatively high concentrations of lactose and its decomposition products and low concentrations of protein and aminonitrogen in the fistula stools when breast milk was fed. When the cow's milk formula was applied, only traces of lactose but high amounts of protein were measured. The microbiological findings are in agreement with the hypothesis that the bacterial flora of the large intestine is influenced by the lactose and protein concentrations in the intestinal content which reach the large intestine.     

Lactose and protein absorption from breast milk and cow's milk preparations and its influence on the intestinal flora. Investigations on two infants with an artificial anus

Lactose and protein absorption from breast milk and a cow's milk preparation enriched up to 7% of lactose were studied in two infants with an artificial anus applied in the ascending colon region. The concentrations of protein, lactose, glucose and galactose were measured in the fistula stools. In addition, the stools were analysed microbiologically. There were relatively high concentrations of lactose and its decomposition products and low concentrations of protein and aminonitrogen in the fistula stools when breast milk was fed. When the cow's milk formula was applied, only traces of lactose but high amounts of protein were measured. The microbiological findings are in agreement with the hypothesis that the bacterial flora of the large intestine is influenced by the lactose and protein concentrations in the intestinal content which reach the large intestine.     

Targeted fortification with human milk analysis: An opportunity for innovation

Human milk's variable macronutrient composition is a necessary consideration when caring for very low birthweight infants. Targeted fortification is the practice of fortifying human milk using its known composition from human milk analysis, rather than its assumed macronutrient values. Utilization of human milk analyzers to measure the protein, fat, lactose, and energy composition within human milk samples has allowed the translation of this practice into the clinical setting. This review discusses the rationale of why targeted fortification is an important practice, what barriers exist in its implementation in the clinical setting, and what research gaps remain to be addressed.     

Lactational capacity of marginally nourished mothers: relationships between maternal nutritional status and quantity and proximate composition of milk

Longitudinal studies of the nutritional status of 60 lactating Bangladeshi mothers from an underprivileged, periurban community and of the quantity and composition of their milk were completed to determine the relationships between maternal nutritional status and lactational capacity. Daily milk production was estimated by 24-hour test-weighing; the nitrogen, fat, lactose, and total energy concentrations of extracted milk samples were analyzed at various stages of lactation to estimate total milk nutrient production. Although the mothers were poorly nourished compared with international reference populations, their lactational capacity was not severely impaired. Average milk production peaked at 750 g/d when the infants were between 5 and 7 months of age. Nitrogen and fat concentrations declined with (log) infant age; lactose concentration increased with (log) infant age (P less than .001). Average concentrations of milk nutrients when the infants were 3 months of age were: nitrogen, 0.161 g/dL; fat, 2.804 g/dL; lactose, 7.92 g/dL; energy, 61.0 kcal/dL. Fat and energy concentrations were significantly greater, and fat and energy amounts tended to be greater, for mothers with larger triceps skinfold thickness or arm circumference. Changes in nutritional status within individual women were also significantly related to the amount and composition of their milk: within-woman increases in triceps skinfold thickness were associated with increases in fat and energy concentrations (P less than .01) and within-woman increases in body weight were associated with increases in the amounts of milk and all major nutrients (P less than .01). Milk production declined significantly during certain months of the year, just before the major harvest period. The findings suggest that, despite their remarkably good lactational capacity, the mothers' milk production was limited to some extent by their nutritional status and may, therefore, be further increased with nutritional improvement.     

Inadequacy of breast milk--a myth or reality?

With the exception of the very poor, lactating mothers from developing countries do not differ significantly from their counterparts in developed countries in terms of the quantity and quality of their breast milk. Healthy women from higher socioeconomic groups can safely exclusively breastfeed their infants for the 1st 4-6 months of life. There is also research evidence from India and other countries that milk from low-income mothers may contain enough energy to sustain infant growth for the same length of time. Poor mothers appear to compensate for the lower fat content of their milk by producing milk with high protein and lactose content. Among the poor, early supplementation of breast milk often results in an increased incidence of gastrointestinal infection and not in significant weight gain. This finding suggests that an effort should be made first to improve the lactation of the mother through nutritional supplementation and counseling before interventions are directed at the infant. Finally, given the role of better educated urban women as trendsetters, an effort should be made to counteract their widespread belief that their milk is insufficient for infant nutrition.     

Iron absorption from human milk, simulated human milk, and proprietary formulas

Studies from our laboratory have shown that iron is better absorbed from human milk than from cow milk and that human milk can provide insufficient iron for infants during their first year. We compared iron availability from human milk with that from other formulas and determined the factors responsible for its superiority. Adults were fed 100 ml of human milk, simulated human milk, simulated human milk containing added lactoferrin, two commercial formulas containing iron, 12 mg/qt, and human milk that had been boiled. The simulated human milk resembled human milk in concentration of protein, fat, carbohydrate, iron, total minerals, calcium, and phosphorus. Iron 59 was added to each feeding and iron incorporation into RBCs was determined 14 days after each feeding. Percent iron absorption was highest from human milk and lowest from the commercial formulas. The simulated human milk supported a 9.0% absorption; addition of lactoferrin reduced this to 4.7%. Net iron absorption was 0.12 mg/liter from human milk and 0.40 and 0.37 mg/liter from the iron-enriched commercial formulas. Absorption of iron from boiled human milk was the same as from the unboiled milk. This study confirms the unique ability of human milk to promote iron absorption. Simple manipulation of the protein, fat, lactose, calcium, phosphorus, or lactoferrin content of proprietary milk did not reproduce the iron absorption demonstrated with human milk.