Bedside analysis of human milk for adjustable nutrition strategy

The Umbilical Cord Creatine Flux and Time Course of Human Milk Creatine across Lactation

(1) Background: The aim of the present paper was to study fetal and infant creatine (Cr) supply to improve nutrition and neuroprotection in term and especially in preterm infants. The primary outcomes were the placental Cr flux at the end of pregnancy and the time course of human milk (HM) Cr. (2) Methods: The estimation of placental Cr flux was based on umbilical arterial and venous cord blood Cr in 10 term infants after elective caesarian section. HM Cr, creatinine (Crn), and macronutrients were measured longitudinally in 10 mothers across the first 6 months of breastfeeding. (3) Results: At the end of pregnancy, the mean fetal Cr flux was negative (-2.07 mmol/min). HM Cr was highest in colostrum, decreased significantly within the first 2 weeks of breastfeeding (p < 0.05), and did not change significantly thereafter. HM Cr was not correlated with HM Crn or macronutrient composition. (4) Conclusions: The present data suggest that fetal endogenous Cr synthesis covers the needs at the end of pregnancy. However, high colostrum Cr and HM Cr levels, independent of macronutrient composition, suggest that there may be a critical Cr demand immediately after birth that needs to be covered by enteral supply.

PsyNBIOsis: Investigating the Association between Maternal Gestational Diabetes, Mental Health, Diet and Childhood Obesity Risk: Protocol for a Prospective, Longitudinal, Observational Study

BACKGROUND

Gestational diabetes mellitus (GDM) is associated with poorer maternal mental health (depression and anxiety). Maternal mental health and GDM are likely to influence diet, which in turn impacts the course of GDM. Maternal diet may also be directly or indirectly associated with changes in infant anthropometry. The aims of this study are to (1) examine the associations between maternal GDM, mental health and diet, and (2) evaluate the associations between these maternal factors, breastmilk composition and infant anthropometry.

METHODS

This prospective, observational, longitudinal cohort study compares a cohort of women with and without GDM. Maternal mental health and diet are assessed using validated questionnaires. Breastmilk composition is measured with the Human Milk Analyzer, and infant body composition is measured with air displacement plethysmography.

SIGNIFICANCE AND IMPACT

Once data have been collected, PsyNBIOsis will provide evidence for the associations between maternal mental health, GDM status and diet, and their impact on breastmilk composition and early infant growth. The results may inform the Developmental Origins of Health and Disease framework and provide data on which to build cost-effective interventions to prevent both the development of mental health issues in mothers and adverse growth patterns in infants.

Carbohydrate content of human milk is affected by seasonal variations: a retrospective observational study

OBJECTIVE

The influence of seasonal variation upon human milk macronutrient content has not been elucidated. This study aimed to compare the macronutrient content of HM produced by lactating mothers during the winter and the summer seasons.

STUDY DESIGN

Macronutrient content of colostrum milk samples collected from lactating mothers of healthy term infants between March 2012 and February 2016 was measured by mid-infrared spectroscopy and compared.

RESULT

The carbohydrate content of the colostrum was significantly higher in the summer season than in the winter season (6.2 ± 1.3 vs. 5.5 ± 1.4, p-value < 0.001). Protein, fat, and energy contents were similar in summer and winter in both groups (protein 2.7 ± 2.1 vs. 2.6 ± 2.2 g/100 ml, fat 2.6 ± 1.9 vs. 2.35 ± 1.9 g/100 ml, and energy 62 ± 19.1 vs. 60.5 ± 21 kcal/100 ml, respectively).

CONCLUSION

The carbohydrate content in colostrum obtained from mothers of term infants was affected by seasonal variations.

Comparing human milk macronutrients measured using analyzers based on mid-infrared spectroscopy and ultrasound and the application of machine learning in data fitting

OBJECTIVE

Fat, carbohydrates (mainly lactose) and protein in breast milk all provide indispensable benefits for the growth of newborns. The only source of nutrition in early infancy is breast milk, so the energy of breast milk is also crucial to the growth of infants. Some macronutrients composition in human breast milk varies greatly, which could affect its nutritional fulfillment to preterm infant needs. Therefore, rapid analysis of macronutrients (including lactose, fat and protein) and milk energy in breast milk is of clinical importance. This study compared the macronutrients results of a mid-infrared (MIR) analyzer and an ultrasound-based breast milk analyzer and unified the results by machine learning.

METHODS

This cross-sectional study included breastfeeding mothers aged 22-40 enrolled between November 2019 and February 2021. Breast milk samples (n = 546) were collected from 244 mothers (from Day 1 to Day 1086 postpartum). A MIR milk analyzer (BETTERREN Co., HMIR-05, SH, CHINA) and an ultrasonic milk analyzer (Honɡyanɡ Co,. HMA 3000, Hebei, CHINA) were used to determine the human milk macronutrient composition. A total of 465 samples completed the tests in both analyzers. The results of the ultrasonic method were mathematically converted using machine learning, while the Bland-Altman method was used to determine the limits of agreement (LOA) between the adjusted results of the ultrasonic method and MIR results.

RESULTS

The MIR and ultrasonic milk analyzer results were significantly different. The protein, fat, and energy determined using the MIR method were higher than those determined by the ultrasonic method, while lactose determined by the MIR method were lower (all p < 0.05). The consistency between the measured MIR and the adjusted ultrasound values was evaluated using the Bland-Altman analysis and the scatter diagram was generated to calculate the 95% LOA. After adjustments, 93.96% protein points (436 out of 465), 94.41% fat points (439 out of 465), 95.91% lactose points (446 out of 465) and 94.62% energy points (440 out of 465) were within the LOA range. The 95% LOA of protein, fat, lactose and energy were - 0.6 to 0.6 g/dl, -0.92 to 0.92 g/dl, -0.88 to 0.88 g/dl and - 40.2 to 40.4 kj/dl, respectively and clinically acceptable. The adjusted ultrasonic results were consistent with the MIR results, and LOA results were high (close to 95%).

CONCLUSIONS

While the results of the breast milk rapid analyzers using the two methods varied significantly, they could still be considered comparable after data adjustments using linear regression algorithm in machine learning. Machine learning methods can play a role in data fitting using different analyzers.

Using Nature to Nurture: Breast Milk Analysis and Fortification to Improve Growth and Neurodevelopmental Outcomes in Preterm Infants

Premature infants are born prior to a critical window of rapid placental nutrient transfer and fetal growth-particularly brain development-that occurs during the third trimester of pregnancy. Subsequently, a large proportion of preterm neonates experience extrauterine growth failure and associated neurodevelopmental impairments. Human milk (maternal or donor breast milk) is the recommended source of enteral nutrition for preterm infants, but requires additional fortification of macronutrient, micronutrient, and energy content to meet the nutritional demands of the preterm infant in attempts at replicating in utero nutrient accretion and growth rates. Traditional standardized fortification practices that add a fixed amount of multicomponent fortifier based on assumed breast milk composition do not take into account the considerable variations in breast milk content or individual neonatal metabolism. Emerging methods of individualized fortification-including targeted and adjusted fortification-show promise in improving postnatal growth and neurodevelopmental outcomes in preterm infants.

Trace element levels in mature breast milk of recently lactating Japanese women

BACKGROUND

Many trace elements are essential for infant growth and development during early life. Their concentrations in breast milk vary depending on social and economic factors. Nonetheless, the present available values in Japan were derived from lactating mothers approximately 15 years ago.

METHODS

Healthy mothers who gave birth to a single infant after 37 weeks of gestation at Teikyo University Hospital were recruited between July 2016 and December 2017. They were encouraged to collect breast milk samples and a self-administered food frequency questionnaire at 1 and 3 months postpartum. Anthropometric data for the mothers and their infants were also collected. Overall, 79 subjects were analyzed after excluding subjects with inadequate data in the food frequency questionnaire, insufficient breast milk samples, and medication that could affect dietary intakes. Trace element concentrations were determined by inductively coupled plasma mass spectrometry, and their correlation with several factors were investigated.

RESULTS

Trace element concentrations were widely distributed as previously reported. Median concentrations of Cr, Mn, Fe, Cu, Zn, Se, and Mo were 0.8, 0.8, 98, 50, 272, 2.2, and 0.7 µg/dL at 1 month postpartum and 0.6, 0.7, 55, 33, 177, 2.1, and 0.7 µg/dL at 3 months postpartum, respectively. There were no correlations between trace element concentrations and either mothers' intakes or infants' growth. In contrast, there were significant correlations between several trace elements and macronutrients in addition to inter-element correlations among almost all trace elements.

CONCLUSIONS

Trace element concentrations in mature breast milk were determined from recently lactating mothers in Japan.

Effect of Freezing Time on Tissue Factor Activity and Macronutrients of Human Milk

Human milk proteins are known as vital molecules for infant development and growth. Tissue factor is one of these human milk proteins that its role in human milk has not been cleared yet. Therefore, the first aim of this study was to detect the tissue factor activity of human milk and also was to investigate the effect of extended freezer storage on the milk tissue factor activity. The relationship between the tissue factor activity and macronutrient content and pH of milk was also investigated in this study. Under this aim, mature human milk samples were obtained from 8 healthy women. Collected human milk samples were pooled and divided into aliquots that were stored at - 20 °C until the day to be analyzed. Milk tissue factor activity, protein, fat, lactose, energy, water, density, and pH levels were determined for up to six months. By two months from the freezing, tissue factor activity did not significantly change but significantly decreased at the end of the six months. From the first month to six months from freezing, lactose, protein, fat, and energy levels showed a significant decline. Milk pH did not change with freezing at the end of 6 months. In conclusion, TF activity maintained its first-day activity until the second month after being pumped. The increased interest in breast milk leads us to believe that the gap existing in the knowledge of breast milk bioactive components like TF will be complemented with new research data.

Infrared analyzers for the measurement of breastmilk macronutrient content in the clinical setting

INTRODUCTION

There is growing interest in the possibility of measuring the macronutrient content of human milk. Several studies that intend to validate commercially available human milk analyzers have been published with inconsistent results. This review will focus on currently available, verified methodologies for analyzing macronutrients in human milk.

AREAS COVERED

A literature search was conducted in the PubMed database. Five milk analyzers were chosen to be included in this review: MIRIS (Uppsala, Sweden) (seven articles found), Calais (Cleveland, United States) (four articles), SpectraStar (Brookfield, United States) (four articles), MilkoScan (Hillerdo, Denmark) (two articles), and Delta LactoScope (Stockholm, Sweden) (one article). The following information was extracted from published manuscripts: measuring device, sample preparation, purpose of the study, type of macronutrients studied, results, and conclusions.

EXPERT OPINION

Infrared spectroscopy can be an accurate and reliable technology for assessing the macronutrient content of human milk, specifically crude protein, and total fat. However, an optimal handling of samples, the development of standardized quality-control protocols, and an improvement in calibration procedures are required before the full implementation of infrared technology in neonatal units.

The Nutritional Composition and Energy Content of Donor Human Milk: A Systematic Review

The American Academy of Pediatrics recommends donor human milk (DHM) as the preferred feeding strategy for preterm infants when the milk of the mother is unavailable, based on conclusive evidence of lower rates of necrotizing enterocolitis with DHM feedings compared with preterm infant formula. The nutritional composition of DHM may differ from maternal milk for many reasons including differences in maternal characteristics, milk collection methods, and the impact of donor milk banking practices. The purpose of this systematic review is to examine the literature regarding research on the fat, protein, carbohydrate, vitamin, and mineral composition of DHM obtained through nonprofit milk banks or commercial entities. PubMed, CINAHL, and Scopus databases were searched for articles published between 1985 and 30 April, 2019. In total, 164 abstracts were screened independently by 2 investigators, and 14 studies met all inclusion criteria. Studies were predominantly small (<50 samples) and measured macronutrients. Few studies assessed vitamins and minerals. Information bias was prevalent due to the use of a variety of analytical methods which influence accuracy and cross-study comparisons. Other sources of information bias included missing information regarding methods for protein and calorie assessment. Despite these limitations, existing research suggests the potential for 2-fold and greater differences in the fat, protein, and energy composition of DHM, with mean values for energy and fat often below clinical reference values expected for human milk. Further research is warranted regarding the nutritional composition of DHM, with a prioritization on measuring macronutrients and micronutrients using established reference methods.

Maternal Health and Nutrition Status, Human Milk Composition, and Growth and Development of Infants and Children: A Prospective Japanese Human Milk Study Protocol

It is unknown whether maternal health and nutrition are related to human milk composition or growth and development of infants and children. Here, we describe a protocol for a prospective five-year cohort study to clarify (i) how maternal health and nutrition, socioeconomic factors, and lifestyles affect human milk composition, and (ii) whether these are associated with growth and development of infants and children. In our study, we recruited 1210 Japanese mothers with singleton pregnancies from 73 obstetrics clinics and hospitals across Japan, between 2014 and 2019. We will measure the following: health information regarding maternal-child dyads using a self-administered questionnaire, maternal nutrition during breastfeeding using a Brief self-administrated Diet History Questionnaire, the development of infants and children using the Kinder Infant Development Scale, and the stress related to child rearing using the Mother’s Child Care Stress Scale. Simultaneously, we will collect human milk every 2 months during the first year after birth to measure its composition and levels of macronutrients. This study will generate useful data to investigate whether health status, nutritional status, lifestyle, and socioeconomic factors affect human milk composition and the growth and development of infants and children.

Successful Full Lactation Achieved by Mothers of Preterm Infants Using Exclusive Pumping

Background: Some mothers of preterm infants suffer from difficulties in initiating and maintaining adequate milk production. This study was designed to investigate the milk production in mothers of preterm infants using hospital-grade breast pumps and to study the nutrient content of their milk. Methods: This was an observational prospective study. Mothers of preterm infants with gestational age < 32 weeks or birth weight < 1,500 g who were admitted to our hospital from August 2016 to December 2017 were recruited. A pumping diary and a questionnaire were completed by mothers (n = 30). Milk samples from before, during, and after each pumping session on days 7 and 14 postpartum were analyzed. Results: The median time to onset of lactogenesis II was 75.4 h. Mean milk output increased gradually, meeting key thresholds of 350 g/d on day 6, 500 g/d on day 8, and close to 750 g/d on day 14. Then, all mean milk outputs were over 750 g/d. The mean milk output exceeded the mean feeding volume on days 7, 14, 21, 28, 35, and 42. Mothers using hospital-grade breast pumps had more cumulative milk production compared with mothers using hand expression. The milk yield on days 7 and 14 were positively correlated to that on days 21, 28, 35, and 42. Milk outputs on days 7, 14, and 42 of mothers with a pumping frequency of ≥ 6 times/d were greater than mothers with a pumping frequency of < 6 times/d. Threshold values for milk output on day 7 (cut-off, 406.8 g/d; sensitivity, 68.2%; specificity, 100%) and day 14 (cut-off, 518.0 g/d; sensitivity, 81.8%; specificity, 100%) were identified as predicting a milk output of more than 750 g/d on day 42. Fat and energy levels were higher in hind-milk than fore- or mixed-milk on days 7 and 14. Those who pumped ≥ 6 times/d had higher levels of fat, carbohydrate, and energy in their milk on day 7. Conclusion: Most preterm infants' mothers using a hospital-grade pump with a pumping frequency of ≥ 6 times/d can reach full lactation successfully. Nutrient analysis of the human milk should be performed.

Accuracy and Reliability of Infrared Analyzers for Measuring Human Milk Macronutrients in a Milk Bank Setting

BACKGROUND

Infrared (IR) analysis is an emerging technology that may be a useful tool for milk banks to manage the nutrient variability in donor human milk.

OBJECTIVE

To evaluate the accuracy, reliability, and comparability of commercial infrared analyzers for measuring human milk macronutrients in a milk bank setting.

METHODS

Three nonprofit milk banks received blinded test kits of human milk that had been assessed using reference methods. Four infrared instruments were used to measure macronutrients as follows: 1 filtered mid-IR, 2 Fourier-transformed full-spectra mid-IR, and 1 near-IR. Twenty-five unique samples were read concurrently for the accuracy arm. An identical sample was read daily for 1 mo for the reliability arm.

RESULTS

Values for R 2 describing relationships with reference methods for total fat, crude protein, and lactose, were as follows: filtered mid-IR, 0.98, 0.94, and 0.48; Fourier-transformed full-spectra mid-IR, 0.97, 0.93, and 0.36 for instrument 1 and 0.98, 0.98, and 0.31 for instrument 2; and near-IR 0.93, 0.93, and 0.12. There was no significant difference between instruments for crude protein and total fat measurements. There were significant differences in carbohydrate measurements between instruments. For 1 mo of daily measurements in the reliability arm, CVs for filtered mid-IR were ≤4.6%, for Fourier-transformed full spectra mid-IR were ≤1.7%, and for near-IR were ≤5.1%.

CONCLUSIONS

Infrared analysis is an accurate and reliable method for measuring crude protein and total fat in a milk bank setting. Carbohydrate measurements are less accurate and are significantly different between instruments, which will likely lead to differences in derived calorie values.

Maternal Undernutrition and Breast Milk Macronutrient Content Are Not Associated with Weight in Breastfed Infants at 1 and 3 Months after Delivery

This study examined whether maternal nutritional intake and breast milk macronutrient content influence the weight of breastfed infants. We investigated 129 healthy mothers with singleton babies born from July 2016 to December 2017 in a university hospital in Tokyo, Japan. Information was obtained by a self-administered food frequency questionnaire at 1 (valid response n = 92; mean age, 34 years) and 3 (n = 57) months after delivery. Breast milk was sampled at 1 and 3 months and the macronutrient contents were analyzed. The average pre-pregnancy body mass index and weight gain during pregnancy were 20.7 ± 2.6 kg/m² and 9.6 ± 3.7 kg, respectively. At 1 month, average maternal calorie intake was 1993 ± 417 kcal/day, which was lower than the intake recommended by Japanese Dietary Reference Intakes for breastfeeding mothers. There were no significant differences with regard to maternal calorie and protein intake, and breast milk macronutrient content between breastfed infants with weight above and below the 25th percentile of its distribution at both 1 and 3 months. This study suggests that suboptimal calorie intake by breastfeeding mothers and breast milk macronutrient content were not associated with weight of their infants at 1 and 3 months after delivery.

Influence of refrigeration or freezing on human milk macronutrients and energy content in early lactation: Results from a tertiary centre survey

BACKGROUND

Neonates with severe conditions that cannot be breastfed should receive fresh or preserved expressed human milk in addition to parenteral nutrition.

OBJECTIVE

To identify the time during lactation when the macronutrients provide maximum energy and evaluate the effect of refrigeration and freezing.

METHODS

We analyzed the composition of fresh milk, refrigerated at +4°C and frozen at -20°C, expressed by mothers of 60 preterm and 30 term infants from a level III maternity, in colostrum, transitional, and mature milk.

RESULTS

In fresh milk, the protein level constantly decreases during lactation, with a significant difference after 3 weeks of lactation. Preterm milk of day 21 and day 30 had significantly lower protein than term milk (1.27 versus 1.43 g/dL, P=0.015 and 1.13 versus 1.28 g/dL, P=0.001). Refrigeration for 72 hours of term milk decreased protein content less than freezing. Preterm colostrum has significantly less protein after 48 hours of refrigeration or freezing. Preterm milk from day 60 lost carbohydrates if refrigerated 72 hours or frozen for 2 months. Lipids in preterm colostrum decrease after 8 weeks of freezing. Refrigeration for up to 72 hours did not change significantly the energy value of colostrum or transitional milk. Freezing preterm milk more than 2 weeks leads to significant loss of energy.

CONCLUSIONS

Milk frozen for more than 2 weeks contains less protein and energy than milk refrigerated for up to 72 hours. In the absence of milk bank access, in common settings, short-term refrigeration is preferable to long-term freezing.

Tolerance of Hydrolyzed Liquid Protein Fortified Human Milk and Effect on Growth in Premature Infants

BACKGROUND

We evaluated tolerance of hydrolyzed liquid protein (LP) supplement added to fortified human milk (HM) to optimize protein intake in preterm infants.

METHODS

A prospective observational study of 31 subjects compared with 31 historic controls, receiving mothers own milk (MOM) and/or donor milk (DM) to assess LP tolerance, growth, and risk for morbidities was conducted. Milk was analyzed for nutrient content. Feeding intolerance, defined as cessation of feedings for ≥48 hours, abdominal distension and/or residuals, necrotizing enterocolitis (NEC), and metabolic acidosis were used to assess safety, while weight and head circumference (HC) were used to evaluate growth.

RESULTS

LP added to powder-fortified HM had no impact on feeding intolerance and NEC. Biochemical parameters showed no metabolic acidosis: blood urea nitrogen levels (first week: median, 13 mg/dL; interquartile range [IQR], 9-16; last week: median, 13 mg/dL; IQR, 10.3-14; P = .94), bicarbonate levels (first week: median, 26.3 mEq/L; IQR, 24-28; last week: median, 28 mEq/L; IQR, 26.3-29.8; P = .10), and pH levels (first week: median, 7.4; IQR, 7.3-7.4; last week: median, 7.4; IQR, 7.37-7.40; P = .5). Weight and HC were not statistically significant. HM analysis showed lower protein and caloric content, respectively (MOM: 0.88 vs DM: 0.77 g/100 mL; P < .0001 and MOM: 18.68 vs DM: 17.96 kcal/oz; P = .02).

CONCLUSIONS

Hydrolyzed LP is well tolerated in preterm infants with no difference in growth rates. Clinicians should focus on the need to maximize both protein and energy to optimize growth.

Body length and occipitofrontal circumference may be good indicators of neurodevelopment in very low birthweight infants - secondary publication

AIM

The aim of this study was to predict the neurological prognosis of very low birthweight (VLBW) infants. We examined the relationship between nutritional status, brain volume measured by magnetic resonance imaging (MRI) and anthropometric measurements of VLBW infants at term-equivalent age (TEA).

METHODS

We evaluated 27 VLBW infants, born at Showa University Hospital in Japan between April 2012 and August 2013, who underwent brain MRI at TEA. Based on their clinical data, we analysed their protein and energy intake.

RESULTS

Median values for the 27 VLBW infants were as follows: gestational age, 29.7 weeks; birthweight 1117 g; protein intake 2.7 g/kg/day and energy intake 97.9 kcal/kg/day. At TEA, the standard deviation scores (SDSs) of body weight, body length and the occipitofrontal circumference (OFC) were -0.8, -1.4 and 0.7, respectively. Multiple regression analysis revealed that the SDSs of body length and the OFC at TEA were significant determinants of white matter volume, but that the SDS of body weight at TEA was not.

CONCLUSION

Our findings suggest that the SDSs of body length and the OFC at TEA may be better indicators than body weight for predicting the development of the central nervous system in VLBW infants receiving nutritional management.

Effect of increased enteral protein intake on plasma and urinary urea concentrations in preterm infants born at < 32 weeks gestation and < 1500 g birth weight enrolled in a randomized controlled trial - a secondary analysis

BACKGROUND

Feeding breast milk is associated with reduced morbidity and mortality, as well as improved neurodevelopmental outcome but does not meet the high nutritional requirements of preterm infants. Both plasma and urinary urea concentrations represent amino acid oxidation and low concentrations may indicate insufficient protein supply. This study assesses the effect of different levels of enteral protein on plasma and urinary urea concentrations and determines if the urinary urea-creatinine ratio provides reliable information about the protein status of preterm infants.

METHODS

Sixty preterm infants (birthweight < 1500 g; gestational age < 32 weeks) were enrolled in a randomized controlled trial and assigned to either a lower-protein group (median protein intake 3.7 g/kg/d) or a higher-protein group (median protein intake 4,3 g/kg/d). Half the patients in the higher-protein group received standardized supplementation with a supplement adding 1.8 g protein/100 ml milk, the other half received individual supplementation depending on the respective mother's milk macronutrient content. Plasma urea concentration was determined in two scheduled blood samples (BS1; BS2); urinary urea and creatinine concentrations in weekly spot urine samples.

RESULTS

The higher-protein group showed higher plasma urea concentrations in both BS1 and BS2 and a higher urinary urea-creatinine-ratio in week 3 and 5-7 compared to the lower-protein group. In addition, a highly positive correlation between plasma urea concentrations and the urinary urea-creatinine-ratio (p < 0.0001) and between actual protein intake and plasma urea concentrations and the urinary urea-creatinine-ratio (both p < 0.0001) was shown.

CONCLUSIONS

The urinary urea-creatinine-ratio, just like plasma urea concentrations, may help to estimate actual protein supply, absorption and oxidation in preterm infants and, additionally, can be determined non-invasively. Further investigations are needed to determine reliable cut-off values of urinary urea concentrations to ensure appropriate protein intake.

TRIAL REGISTRATION

Clinicaltrials.gov; NCT01773902 registered 15 January 2013, retrospectively registered.

Validation of mid-infrared spectroscopy for macronutrient analysis of human milk

OBJECTIVE

Human milk has considerable variation in its composition. Hence, the nutrient profile is only an estimate and can result in under- or over-estimation of the intake of preterm infants. Mid-infrared (MIR) spectroscopy is an evolving technique for analyzing human milk but needs validation before use in clinical practice.

STUDY DESIGN

Human milk samples from 35 mothers delivering at 35 weeks to term gestation were analyzed for macronutrients by MIR spectroscopy and by standard laboratory methods using Kjeldahl assay for protein, Mojonnier assay for fat and high-pressure liquid chromatography assay for lactose.

RESULTS

MIR analysis of the macronutrients in human milk correlated well with standard laboratory tests with intraclass correlation coefficients of 0.997 for fat, 0.839 for protein and 0.776 for lactose. Agreement between the two methods was excellent for fat, and moderate for protein and lactose (P<0.001).

CONCLUSIONS

This methodological paper provides evidence that MIR spectroscopy can be used to analyze macronutrient composition of human milk. Agreement between the methodologies varies by macronutrient.

Assessment of human milk composition using mid-infrared analyzers requires calibration adjustment

OBJECTIVE

Nutrient composition of human milk (HM) is highly variable. Targeted HM fortification has been proposed to address these variations and reduce the cumulative nutritional deficit in preterm infants. Near-infrared analysis is used to measure the protein and fat content in HM; however, the reliability of this technique has not been evaluated. The objective of this study is to evaluate the reproducibility and accuracy of two generations of HM analyzers (HMA1 and HMA2) in estimating protein and lipid contents.

STUDY DESIGN

Reproducibility was assessed by analyzing in duplicate 146 and 128 HM samples with HMA1 and HMA2 (Miris), respectively. To evaluate the accuracy, lipid and protein concentrations were assessed in 31 and 39 samples using HMA1 or HMA2, respectively. Values were compared with measurements obtained using reference methods and correction equations were calculated. After applying the correction equations on 12 HM samples, the performance of the two devices were compared and the equation was validated according to the reference methods.

RESULTS

The coefficients of variation for protein and lipid assessments were below 3% for both HMA1 and HMA2. Protein concentrations were significantly underestimated by HMA2 (-0.53±0.23 g dl^-1). Lipid content was significantly overestimated by both devices, but the error was greater with HMA1 (0.76±0.48 g dl^-1) than with HMA2 (0.36±0.33 g dl^-1). Correction equations were specific for each generation of HMA. Finally, after correction, both instruments provided similar and accurate results.

CONCLUSION

HMAs require calibration adjustment before their use in clinical practice, to avoid inappropriate HM fortification.

Just add water: Accuracy of analysis of diluted human milk samples using mid-infrared spectroscopy

OBJECTIVE

To determine the maximum dilution of human milk (HM) that yields reliable results for protein, fat and lactose when analyzed by mid-infrared spectroscopy.

STUDY DESIGN

De-identified samples of frozen HM were obtained. Milk was thawed and warmed (40°C) prior to analysis. Undiluted (native) HM was analyzed by mid-infrared spectroscopy for macronutrient composition: total protein (P), fat (F), carbohydrate (C); Energy (E) was calculated from the macronutrient results. Subsequent analyses were done with 1 : 2, 1 : 3, 1 : 5 and 1 : 10 dilutions of each sample with distilled water. Additional samples were sent to a certified lab for external validation.

RESULTS

Quantitatively, F and P showed statistically significant but clinically non-critical differences in 1 : 2 and 1 : 3 dilutions. Differences at higher dilutions were statistically significant and deviated from native values enough to render those dilutions unreliable. External validation studies also showed statistically significant but clinically unimportant differences at 1 : 2 and 1 : 3 dilutions.

CONCLUSIONS

The Calais Human Milk Analyzer can be used with HM samples diluted 1 : 2 and 1 : 3 and return results within 5% of values from undiluted HM. At a 1 : 5 or 1 : 10 dilution, however, results vary as much as 10%, especially with P and F. At the 1 : 2 and 1 : 3 dilutions these differences appear to be insignificant in the context of nutritional management. However, the accuracy and reliability of the 1 : 5 and 1 : 10 dilutions are questionable.

"Bed Side" Human Milk Analysis in the Neonatal Intensive Care Unit: A Systematic Review

Human milk analyzers can measure macronutrient content in native breast milk to tailor adequate supplementation with fortifiers. This article reviews all studies using milk analyzers, including (i) evaluation of devices, (ii) the impact of different conditions on the macronutrient analysis of human milk, and (iii) clinical trials to improve growth. Results lack consistency, potentially due to systematic errors in the validation of the device, or pre-analytical sample preparation errors like homogenization. It is crucial to introduce good laboratory and clinical practice when using these devices; otherwise a non-validated clinical usage can severely affect growth outcomes of infants.

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-1 and 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-1 vs 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.

Optimal Distribution and Utilization of Donated Human Breast Milk

BACKGROUND

The nutritional content of donated expressed breast milk (DEBM) is variable. Using DEBM to provide for the energy requirements of neonates is challenging.

OBJECTIVE

The authors hypothesized that a system of DEBM energy content categorization and distribution would improve energy intake from DEBM.

METHODS

We compared infants' actual cumulative energy intake with projected energy intake, had they been fed using our proposed system. Eighty-five milk samples were ranked by energy content. The bottom, middle, and top tertiles were classified as red, amber, and green energy content categories, respectively. Data on 378 feeding days from 20 babies who received this milk were analyzed. Total daily intake of DEBM was calculated in mL/kg/day and similarly ranked. Infants received red energy content milk, with DEBM intake in the bottom daily volume intake tertile; amber energy content milk, with intake in the middle daily volume intake tertile; and green energy content milk when intake reached the top daily volume intake tertile.

RESULTS

Actual median cumulative energy intake from DEBM was 1612 (range, 15-11 182) kcal. Using DEBM with the minimum energy content from the 3 DEBM energy content categories, median projected cumulative intake was 1670 (range 13-11 077) kcal, which was not statistically significant ( P = .418). Statistical significance was achieved using DEBM with the median and maximum energy content from each energy content category, giving median projected cumulative intakes of 1859 kcal ( P = .0006) and 2280 kcal ( P = .0001), respectively.

CONCLUSION

Cumulative energy intake from DEBM can be improved by categorizing and distributing milk according to energy content.

Preterm human milk composition: a systematic literature review

There are wide variations in the macronutrient values adopted by neonatal intensive care units and industry to fortify milk in efforts to achieve recommended intakes for preterm infants. Contributing to this is the variation in macronutrient composition of preterm milk between and within mothers and the variable quality of milk analyses used to determine the macronutrient content of milk. We conducted a systematic review of the literature using articles published in English between 1959 and 2013 that reported the concentrations of one or more macronutrients or energy content in human preterm milk, sampled over a representative 24-h period. Searched medical databases included Ovid Medline, Scopus, CINAHL and the Cochrane Library. Results are presented as mean values and ranges for each macronutrient during weeks 1-8 of lactation, and preferred mean values (g/100 ml) for colostrum (week 1) and mature milk (weeks 2-8; protein: 1·27, fat: 3·46, lactose: 6·15 and carbohydrate: 7·34), using data from studies employing the highest-quality analyses. Industry-directed fortification practices using these mean values fail to meet protein targets for infants weighing <1000 g when the fortified milk is fed <170-190 ml/kg per d, and the protein:energy ratio of the fortified milk is inadequate. This study aimed to provide additional information to industry in order to guide their future formulation of breast milk fortifiers. Quality macronutrient analyses of adequately sampled preterm breast milk would improve our understanding of the level of fortification needed to meet recommended protein and energy intakes and growth targets, as well as support standardised reporting of nutritional outcomes.

Calibration Adjustment of the Mid-infrared Analyzer for an Accurate Determination of the Macronutrient Composition of Human Milk

BACKGROUND

Human milk composition analysis seems essential to adapt human milk fortification for preterm neonates. The Miris human milk analyzer (HMA), based on mid-infrared methodology, is convenient for a unique determination of macronutrients. However, HMA measurements are not totally comparable with reference methods (RMs).

OBJECTIVE

The primary aim of this study was to compare HMA results with results from biochemical RMs for a large range of protein, fat, and carbohydrate contents and to establish a calibration adjustment.

METHODS

Human milk was fractionated in protein, fat, and skim milk by covering large ranges of protein (0-3 g/100 mL), fat (0-8 g/100 mL), and carbohydrate (5-8 g/100 mL). For each macronutrient, a calibration curve was plotted by linear regression using measurements obtained using HMA and RMs.

RESULTS

For fat, 53 measurements were performed, and the linear regression equation was HMA = 0.79RM + 0.28 (R(2) = 0.92). For true protein (29 measurements), the linear regression equation was HMA = 0.9RM + 0.23 (R(2) = 0.98). For carbohydrate (15 measurements), the linear regression equation was HMA = 0.59RM + 1.86 (R(2) = 0.95). A homogenization step with a disruptor coupled to a sonication step was necessary to obtain better accuracy of the measurements. Good repeatability (coefficient of variation < 7%) and reproducibility (coefficient of variation < 17%) were obtained after calibration adjustment.

CONCLUSION

New calibration curves were developed for the Miris HMA, allowing accurate measurements in large ranges of macronutrient content. This is necessary for reliable use of this device in individualizing nutrition for preterm newborns.

Human Milk Analyser shows that the lactation period affects protein levels in preterm breastmilk

AIM

This study measured the composition of preterm human breastmilk, particularly the protein content, with the MIRIS Human Milk Analyser, compared our results with published values and determined the relationship between protein content and lactation period.

METHODS

We analysed 83 samples of 24-hour pooled human milk from 76 mothers who delivered preterm infants weighing under 1500 g at less than 32 weeks of gestational age. The milk's protein, fat and energy were measured by the MIRIS Human Milk Analyser and compared to reference values. The relationship between protein content and lactation period was quantified.

RESULTS

On average, the samples contained 1.1 ± 0.37 g (0.2-2.2 g) of protein, 3.2 ± 0.85 g (range 1.1-6.1 g) of fat, 6.6 ± 0.34 g of lactose (5.5-8.0 g) and 60 ± 11 kcal (39-94 kcal) of energy per 100 mL. The wide variations in macronutrient content were not influenced by the gestational age of the infant and the lactation day results from 70 of the mothers correlated inversely with the protein content (p < 0.0001; r = -0.42). The MIRIS proved useful, but some adjustments are needed.

CONCLUSION

Variations in macronutrients were high in the breastmilk of women who delivered preterm babies and the protein content decreased with lactation. With adjustments, the MIRIS might provide a helpful tool for individualised fortification.

Validation of Correction Algorithms for Near-IR Analysis of Human Milk in an Independent Sample Set-Effect of Pasteurization

Commercial infrared (IR) milk analyzers are being increasingly used in research settings for the macronutrient measurement of breast milk (BM) prior to its target fortification. These devices, however, may not provide reliable measurement if not properly calibrated. In the current study, we tested a correction algorithm for a Near-IR milk analyzer (Unity SpectraStar, Brookfield, CT, USA) for fat and protein measurements, and examined the effect of pasteurization on the IR matrix and the stability of fat, protein, and lactose. Measurement values generated through Near-IR analysis were compared against those obtained through chemical reference methods to test the correction algorithm for the Near-IR milk analyzer. Macronutrient levels were compared between unpasteurized and pasteurized milk samples to determine the effect of pasteurization on macronutrient stability. The correction algorithm generated for our device was found to be valid for unpasteurized and pasteurized BM. Pasteurization had no effect on the macronutrient levels and the IR matrix of BM. These results show that fat and protein content can be accurately measured and monitored for unpasteurized and pasteurized BM. Of additional importance is the implication that donated human milk, generally low in protein content, has the potential to be target fortified.

Comparing different methods of human breast milk fortification using measured v. assumed macronutrient composition to target reference growth: a randomised controlled trial

The variable content of human breast milk suggests that its routine fortification may result in sub-optimal nutritional intakes and growth. In a pragmatic trial, we randomised infants born below 30 weeks of gestation to either the intervention (Igp) of fortifying milk on measured composition according to birth weight criteria and postmenstrual age (PMA) or our routine practice (RPgp) of fortifying on assumed milk composition to target 3·8-4·4 g protein/kg per d and 545-629 kJ/kg per d. Milk composition was measured using the MIRIS® Human Milk Analyser. Percentage fat mass (%FM) was measured using PEA POD (COSMED). The effects of macronutrient intakes and clinical variables on growth were assessed using mixed model analysis. Mean measured protein content (1·6 g/100 ml) was higher than the assumed value (1·4 g/100 ml), often leading to lower amounts of fortifier added to the milk of intervention infants. At discharge (Igp v. RPgp), total protein (3·2 (SD 0·3) v. 3·4 (SD 0·4) g; P=0·067) and energy (456 (SD 39) v. 481 (SD 48) kJ; P=0·079) intakes from all nutrition sources, weight gain velocity (11·4 (SD 1·4) v. 12·1 (SD 1·6) g/kg per d; P=0·135) and %FM (13·7 (SD 3·6) v.13·6 (SD 3·5) %; P=0·984) did not significantly differ between groups. A protein intake >3·4 g/kg per d reduced %FM by 2%. Nutrition and growth was not improved by targeting milk fortification according to birth weight criteria and PMA using measured milk composition, compared with routine practice. Targeting fortification on measured composition is labour intensive, requiring frequent milk sampling and precision measuring equipment, perhaps reasons for its limited practice. Guidance around safe upper levels of milk fortification is needed.

Circadian Macronutrients Variations over the First 7 Weeks of Human Milk Feeding of Preterm Infants

BACKGROUND

Little is known about circadian variations of macronutrients content of expressed preterm human milk (HM). This study evaluated diurnal variations of macronutrients and energy content of preterm HM over the first 7 weeks of lactation and tested the hypothesis that values obtained during a morning sample are predictive of those obtained from an evening sample.

MATERIALS AND METHODS

Expressed HM was obtained from 32 mothers of preterm infants (26-33 weeks in gestational age), who routinely expressed all their milk every 3 hours from the beginning of the second to the seventh week after delivery. One aliquot was obtained from the first morning expression and the second from the evening expression. Energy and macronutrients contents were measured using an HM analyzer.

RESULTS

Mean fat and energy contents of all samples obtained during the whole period were significantly higher in evening samples (p < 0.0001). There were no significant differences between morning and evening carbohydrates and protein contents. Concentrations of protein, carbohydrates, and fat from morning samples were predictive of evening concentrations to different extents (R(2) = 0.720, R(2) = 0.663, and R(2) = 0.20, respectively; p < 0.02). The predictability of evening values by morning values was not influenced by the week of lactation at sampling or by individual patients. In repeated-measures analysis of variance performed on 11 patients who completed the whole 7-week period, over time, there was a significant decrease in fat, energy, and protein contents, whereas carbohydrates content remained unchanged. Day-night differences remained significant only for fat content.

CONCLUSIONS

Circadian variations in fat and energy concentrations of HM are consistent over the first 7 weeks of lactation. There are no consistent circadian variations in HM protein and carbohydrates. Over a given day, there are little variations in protein and carbohydrates content, but fat concentrations are more variable, and evening values are less well predicted by morning sample analysis than values for protein or carbohydrates.

Human Milk Analysis Using Mid-Infrared Spectroscopy

BACKGROUND

The composition of human milk is known to vary with length of gestation, stage of lactation, and other factors. Human milk contains all nutrients required for infant health but requires fortification to meet the needs of low-birth-weight infants. Without a known nutrient profile of the mother's milk or donor milk fed to a baby, the composition of the fortified product is only an estimate. Human milk analysis has the potential to improve the nutrition care of high-risk newborns by increasing the information about human milk composition. Equipment to analyze human milk is available, and the technology is rapidly evolving. This pilot study compares mid-infrared (MIR) spectroscopy to reference laboratory milk analysis.

METHODS

After obtaining informed consent, we collected human milk samples from mothers of infants weighing <2 kg at birth. Duplicate samples were analyzed for macronutrients by MIR and by reference laboratory analysis including Kjeldahl for protein, Mojonnier for fat, and high-pressure liquid chromatography for lactose. Intraclass correlation coefficients, Bland-Altman scatter plots, and paired t tests were used to compare the two methods.

RESULTS

No significant differences were detected between the macronutrient content of human milk obtained by MIR vs reference laboratory analysis.

CONCLUSIONS

MIR analysis appears to provide an accurate assessment of macronutrient content in expressed human milk from mothers of preterm infants. The small sample size of this study limits confidence in the results. Measurement of lactose is confounded by the presence of oligosaccharides. Human milk analysis is a potentially useful tool for establishing an individualized fortification plan.

Surface Tension Triggered Wetting and Point of Care Sensor Design

Rapid, simple, and inexpensive point-of-care (POC) medical tests are of significant need around the world. The transition between nonwetting and wetted states is used to create instrument-free surface tension sensors for POC diagnosis, using a layered electrospun mesh with incorporated dye to change color upon wetting.

Macronutrient composition of human milk from Korean mothers of full term infants born at 37-42 gestational weeks

BACKGROUND/OBJECTIVES

Breast milk is the best available food for optimum growth and development of infants and the breastfeeding rate is increasing in Korea. The purpose of this study is to measure the concentrations of macronutrients and to evaluate their changes according to lactation period in breast milk from lactating Korean women.

SUBJECTS/METHODS

Milk samples were obtained from 2,632 healthy lactating women (mean age; 32.0 ± 3.3 years), where the lactating period was up to a period of 8 months, who also volunteered to participate in the Human Milk Macronutrient Analysis Research. Lactose, protein, fat and water content in the breast milk samples were analyzed with infrared spectrometry using MilkoScan FT-2.

RESULTS

The mean macronutrient composition per 100 mL of mature breast milk was 7.1 g for lactose, 1.4 g for protein and 3.0 g for fat, and energy content was 61.1 kcal. The protein concentration was significantly lower in milk samples at 1-2 weeks (2.0 g/dL) to 2-3 months (1.4 g/dL) than those at 0-1 week (2.2 g/dL), but it was similar among samples from 3-4 months to 7-8 months (1.3 g/dL). Mean lipid levels varied among different lactational period groups (2.7-3.2 g/dL), but presented no significant difference. Lactose concentration in the milk samples did not differ with lactation period. Maternal body mass index was positively related to protein and lipid breast milk contents, but was negatively related to lactose content. General linear models examining the associations between maternal variables and milk macronutrient content revealed that lactation period had a major impact on protein and lipid, but not on lactose content in breast milk.

CONCLUSIONS

These results warrant future studies to explore factors that may be associated with changes in macronutrient content in human milk.

Multiplatform characterization of dynamic changes in breast milk during lactation

The multicomponent analysis of human breast milk (BM) by metabolic profiling is a new area of study applied to determining milk composition, and is capable of associating BM composition with maternal characteristics, and subsequent infant health outcomes. A multiplatform approach combining HPLC‐MS and ultra‐performance LC‐MS, GC‐MS, CE‐MS, and ¹H NMR spectroscopy was used to comprehensively characterize metabolic profiles from seventy BM samples. A total of 710 metabolites spanning multiple molecular classes were defined. The utility of the individual and combined analytical platforms was explored in relation to numbers of metabolites identified, as well as the reproducibility of the methods. The greatest number of metabolites was identified by the single phase HPLC‐MS method, while CE‐MS uniquely profiled amino acids in detail and NMR was the most reproducible, whereas GC‐MS targeted volatile compounds and short chain fatty acids. Dynamic changes in BM composition were characterized over the first 3 months of lactation. Metabolites identified as altering in abundance over lactation included fucose, di‐ and triacylglycerols, and short chain fatty acids, known to be important for infant immunological, neurological, and gastrointestinal development, as well as being an important source of energy. This extensive metabolic coverage of the dynamic BM metabolome provides a baseline for investigating the impact of maternal characteristics, as well as establishing the impact of environmental and dietary factors on the composition of BM, with a focus on the downstream health consequences this may have for infants.

Implementation of a human milk management center

Current hospital practices surrounding the use of human milk and fortification are suboptimal. Safety of milk preparation should be a priority, as should optimization of the milk to meet the nutritional needs of hospitalized infants. This article describes the implementation of a human milk management center (HMMC) at a children's hospital. This centralized center allows for milk to be safely prepared under aseptic technique. In addition, the HMMC staff can analyze milk composition. The widely variable nutrient composition of human milk has been well established and, therefore, should be considered when fortifying human milk. The HMMC staff have the ability to perform creamatocrits on milk, conduct human milk nutrient analysis, and make skim milk for infants. The processes for developing an HMMC are also detailed in this article.

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

OBJECTIVES

to 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.

METHOD

an 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.

RESULTS

the 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.

CONCLUSION

the route of administration by continuous infusion showed the greatest influence on fat loss among all the processes required for human milk administration.

Rapid measurement of macronutrients in breast milk: How reliable are infrared milk analyzers?

BACKGROUND & AIMS

Significant biological variation in macronutrient content of breast milk is an important barrier that needs to be overcome to meet nutritional needs of preterm infants. To analyze macronutrient content, commercial infrared milk analyzers have been proposed as efficient and practical tools in terms of efficiency and practicality. Since milk analyzers were originally developed for the dairy industry, they must be validated using a significant number of human milk samples that represent the broad range of variation in macronutrient content in preterm and term milk. Aim of this study was to validate two milk analyzers for breast milk analysis with reference methods and to determine an effective sample pretreatment. Current evidence for the influence of (i) aliquoting, (ii) storage time and (iii) temperature, and (iv) vessel wall adsorption on stability and availability of macronutrients in frozen breast milk is reviewed.

METHODS

Breast milk samples (n = 1188) were collected from 63 mothers of preterm and term infants. Milk analyzers: (A) Near-infrared milk analyzer (Unity SpectraStar, USA) and (B) Mid-infrared milk analyzer (Miris, Sweden) were compared to reference methods, e.g. ether extraction, elemental analysis, and UPLC-MS/MS for fat, protein, and lactose, respectively.

RESULTS

For fat analysis, (A) measured precisely but not accurately (y = 0.55x + 1.25, r(2) = 0.85), whereas (B) measured precisely and accurately (y = 0.93x + 0.18, r(2) = 0.86). For protein analysis, (A) was precise but not accurate (y = 0.55x + 0.54, r(2) = 0.67) while (B) was both precise and accurate (y = 0.78x + 0.05, r(2) = 0.73). For lactose analysis, both devices (A) and (B) showed two distinct concentration levels and measured therefore neither accurately nor precisely (y = 0.02x + 5.69, r(2) = 0.01 and y = -0.09x + 6.62, r(2) = 0.02 respectively). Macronutrient levels were unchanged in two independent samples of stored breast milk (-20 °C measured with IR; -80 °C measured with wet chemistry) over a period of 14 months.

CONCLUSIONS

Milk analyzers in the current configuration have the potential to be introduced in clinical routine to measure fat and protein content, but will need major adjustments.

Rapid measurement of human milk macronutrients in the neonatal intensive care unit: accuracy and precision of fourier transform mid-infrared spectroscopy

BACKGROUND

Although it is well established that human milk varies widely in macronutrient content, it remains common for human milk fortification for premature infants to be based on historic mean values. As a result, those caring for premature infants often underestimate protein intake. Rapid precise measurement of human milk protein, fat, and lactose to allow individualized fortification has been proposed for decades but remains elusive due to technical challenges.

OBJECTIVE

This study aimed to evaluate the accuracy and precision of a Fourier transform (FT) mid-infrared (IR) spectroscope in the neonatal intensive care unit to measure human milk fat, total protein, lactose, and calculated energy compared with standard chemical analyses.

METHODS

One hundred sixteen breast milk samples across lactation stages from women who delivered at term (n = 69) and preterm (n = 5) were analyzed with the FT mid-IR spectroscope and with standard chemical methods. Ten of the samples were tested in replicate using the FT mid-IR spectroscope to determine repeatability.

RESULTS

The agreement between the FT mid-IR spectroscope analysis and reference methods was high for protein and fat and moderate for lactose and energy. The intra-assay coefficients of variation for all outcomes were less than 3%.

CONCLUSION

The FT mid-IR spectroscope demonstrated high accuracy in measurement of total protein and fat of preterm and term milk with high precision.

Is fat content of human milk decreased by infusion?

BACKGROUND

Human milk (HM) is the optimum nutrition for preterm infants. Previous studies showed that tube infusion decreased the fat content in thawed HM. The aim of this study was to determine if freezing–thawing is the main reason for decrease of fat content. In neonatal intensive care units, thawed HM is used in general, therefore the aim of this study was to investigate fat loss during tube infusion with regard to changes in tube size, material, and infusion rate.

METHODS

First, pre-infusion and post-infusion fat content was measured in 15 fresh HM, 10 thawed HM and 6 formula samples. We compared post-infusion and pre-infusion fat content as well as the percent decrease in fat concentration among fresh HM, thawed HM and formula samples. Second, we measured the fat content of 160 thawed HM samples infused via four different diameters (3–6 Fr), two types of material (DEHP-free and PVC-free), and two infusion rates (30 or 60 min). We compared the percent decrease in fat concentration among four different tube sizes, between DEHP-free and PVC-free tubes, and between 30 and 60 min infusion durations.

RESULTS

Post-infusion fat content was significantly decreased compared to before infusion in thawed HM and fresh HM but not in formula. Given that thawed HM resulted in larger decrease in fat content, we performed a second experiment and found no difference regarding differing size, materials or infusion rate.

CONCLUSIONS

There was a far greater decrease in the post-infusion fat content of thawed HM compared to fresh HM under all test conditions.

Effect of mode of delivery on macronutrient content of breast milk

OBJECTIVE

To determine the effect of delivery type on macronutrient content of colostral milk.

MATERIALS AND METHODS

The study was conducted at Zekai Tahir Burak Maternity Teaching Hospital. Colostral milk samples from term lactating mothers who gave birth by vaginal or cesarean delivery (CD) were obtained on the 2nd postpartum day. Milk protein, fat, carbohydrate (CHO) and energy levels were measured by using a mid-infrared human milk analyzer.

RESULTS

A total of 204 term lactating mothers were recruited to the study; 111 mothers gave birth by vaginal route and 93 mothers by CD. Protein levels were statistically lower in colostral milk of mothers after CD compared to mothers who delivered vaginally (median 2.4 (range 0.3-6.4) g/dl versus 3 (0.5-6.3) g/dl, respectively; p = 0.036). Colostral fat, CHO and energy levels were similar between groups. In linear regression analysis, CD and maternal age were independently associated with lower protein content in colostrum.

CONCLUSION

Vaginal delivery is associated with higher colostrum protein content. Hormonal activity induced by labor pain and uterine contractions might account for the alterations in the protein composition of human milk to facilitate optimal development of important physiologic functions in newborns.

Creamatocrit analysis of human milk overestimates fat and energy content when compared to a human milk analyzer using mid-infrared spectroscopy

BACKGROUND AND OBJECTIVE

Human milk (HM) is the preferred feeding for human infants but may be inadequate to support the rapid growth of the very-low-birth-weight infant. The creamatocrit (CMCT) has been widely used to guide health care professionals as they analyze HM fortification; however, the CMCT method is based on an equation using assumptions for protein and carbohydrate with fat as the only measured variable. The aim of the present study was to test the hypothesis that a human milk analyzer (HMA) would provide more accurate data for fat and energy content than analysis by CMCT.

METHODS

Fifty-one well-mixed samples of previously frozen expressed HM were obtained after thawing. Previously assayed "control" milk samples were thawed and also run with unknowns. All milk samples were prewarmed at 40°C and then analyzed by both CMCT and HMA. CMCT fat results were substituted in the CMCT equation to reach a value for energy (kcal/oz). Fat results from HMA were entered into a computer model to reach a value for energy (kcal/oz). Fat and energy results were compared by paired t test with statistical significance set at P < 0.05. An additional 10 samples were analyzed locally by both methods and then sent to a certified laboratory for quantitative analysis. Results for fat and energy were analyzed by 1-way analysis of variance with statistical significance set at P < 0.05.

RESULTS

Mean fat content by CMCT (5.8 ± 1.9 g/dL) was significantly higher than by HMA (3.2 ± 1.1 g/dL, P < 0.001). Mean energy by CMCT (21.8 ± 3.4 kcal/oz) was also significantly higher than by HMA (17.1 ± 2.9, P < 0.001). Comparison of biochemical analysis with HMA of the subset of milk samples showed no statistical difference for fat and energy, whereas CMCT was significantly higher than for both fat (P < 0.001) and energy (P = 0.002).

CONCLUSIONS

The CMCT method appears to overestimate fat and energy content of HM samples when compared with HMA and biochemical methods.

Four-week nutritional audit of preterm infants born <33 weeks gestation

AIM

Preterm nutritional audits have previously been conducted using assumed milk composition. We audited protein and energy intakes in the first 28 days of preterm life using both assumed milk composition and milk analysis to assess their effect on weight gain and to determine if the recommended reasonable range of intakes were met.

METHODS

Parenteral and enteral intakes and weight gain were recorded daily for infants (n = 63) born <33 weeks gestation, using assumed milk composition. Macronutrient composition was determined by milk analysis for a subset of infants (n = 36). Linear mixed models analysis was used to assess the influence of energy and protein intakes on weight gain.

RESULTS

(Data median (range)): Infants (n = 63) gestation and birth weight were 30 (24-32) weeks and 1400 (540-2580) g, respectively. Macronutrient milk composition was variable: protein 16.6 (13.4-27.6) g/L, fat 46.1 (35.0-62.4) g/L, lactose 68.0 (50.9-74.8) g/L, energy 3074 (2631-3761) kJ/L. Intakes based on measured composition differed from assumed. Protein intake was significantly associated with weight gain. Compared to infants with longer gestations, those born <28 weeks gestation were fed lower volumes, were more reliant on parenteral nutrition, took an additional seven days to transition to fortified feeds and median weight gain velocity took a fortnight longer to reach targets.

CONCLUSION

Preterm milk composition is variable and routine fortification using assumed composition may result in inappropriate nutrition. Fortification regimens stratified by birth gestation may be necessary to achieve preterm nutrition and growth targets. Milk analysis is required for accurate nutritional audit.

Field and laboratory methods in human milk research

Human milk is a complex and variable fluid of increasing interest to human biologists who study nutrition and health. The collection and analysis of human milk poses many practical and ethical challenges to field workers, who must balance both appropriate methodology with the needs of participating mothers and infants and logistical challenges to collection and analysis. In this review, we address various collection methods, volume measurements, and ethical considerations and make recommendations for field researchers. We also review frequently used methods for the analysis of fat, protein, sugars/lactose, and specific biomarkers in human milk. Finally, we address new technologies in human milk research, the MIRIS Human Milk Analyzer and dried milk spots, which will improve the ability of human biologists and anthropologists to study human milk in field settings.

Effect of freezing time on macronutrients and energy content of breastmilk

BACKGROUND

In neonatal units and human milk banks freezing breastmilk at less than -20 °C is the choice for preserving it. Scientific evidence in relation to the loss of nutritional quality during freezing is rare. Our main aim in this study is to determine the effect of freezing time up to 3 months on the content of fat, total nitrogen, lactose, and energy. Our secondary aim is to assess whether ultrasonic homogenization of samples enables a more suitable reading of breastmilk macronutrients with a human milk analyzer (HMA) (MIRIS, Uppsala, Sweden).

METHODS

Refrigerated breastmilk samples were collected. Each sample was divided into six pairs of aliquots. One pair was analyzed on day 0, and the remaining pairs were frozen and analyzed, one each at 7, 15, 30, 60, and 90 days later. For each pair, one aliquot was homogenized by stirring, and the other by applying ultrasound. Samples were analyzed with the HMA.

RESULTS

By 3 months from freezing with the two homogenization methods, we observed a relevant and significant decline in the concentration of fat and energy content. The modification of total nitrogen and lactose was not constant and of lower magnitude. The absolute concentration of all macronutrients and calories was greater with ultrasonic homogenization.

CONCLUSIONS

After 3 months from freezing at -20 °C, an important decrease in fat and caloric content is observed. Correct homogenization is fundamental for correct nutritional analysis.

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.

The macronutrients in human milk change after storage in various containers

BACKGROUND

The concentrations of macronutrients in human milk can be influenced by various processes, such as storage, freezing, and thawing, that are performed by lactating working mothers and breast milk banks. We evaluated the impact of various containers on the nutrient concentrations in human milk.

METHODS

A total of 42 breast milk samples from 18 healthy lactating mothers were collected. A baseline macronutrient concentration was determined for each sample. Then, the breast milk samples were divided and stored in nine different commercial milk containers. After freezing at -20°C for 2 days, the milk samples were thawed and analyzed again. A midinfrared human milk analyzer (HMA) was used to measure the protein, fat, and carbohydrate contents.

RESULTS

There was a significant decrease in the fat content following the storage, freezing, and thawing processes, ranging from 0.27-0.30 g/dL (p=0.02), but no significant decrease in energy content (p=0.069) was noted in the nine different containers. There were statistically significant increases in protein and carbohydrate concentrations in all containers (p=0.021 and 0.001, respectively), however there were no significant differences between the containers in terms of fat, protein, carbohydrate, or energy contents.

CONCLUSION

Human milk, when subjected to storage, freezing, and thawing processes, demonstrated a significant decrease in fat content (up to 9% reduction) in various containers. It is better for infants to receive milk directly from the mother via breastfeeding. More studies are warranted to evaluate the effects of milk storage on infant growth and development.

Quantification of lactose content in human and cow's milk using UPLC-tandem mass spectrometry

A sensitive, accurate, and specific quantitative UPLC-MS/MS method was developed for lactose measurement of cow's and human milk and validated with cow's milk samples certified by an external laboratory. The new method employs only a dilution of raw cow's and human milk for simple preparation with no need to remove protein and fat prior to analysis with UPLC-MS/MS. It was operated in negative mode to detect lactose molecules and labeled (13)C(12)-lactose with the highest sensitivity. The principle advantages of the new LC-MS/MS method were: completed lactose determination in 5 min, absolute recovery of 97-107%, lower limit of detection <5 ng/L, and 99% linearity over the concentration range of 0.7-4.4 mg/L for both cow's and human milk. The mean lactose concentration of 51 human milk samples was measured as 56.8 ± 5.5 g/L ranging from 43 to 65 g/L. The described method represents validated lactose analysis with high accuracy and precision for a routine lactose determination in raw human milk.

Evaluation of a mid-infrared analyzer for the determination of the macronutrient composition of human milk

A mid-infrared human milk analyzer (HMA) is designed to measure the macronutrients in human milk over a wide range of concentrations. Human milk samples (N = 30, 4 different dilutions each) were used to compare the macronutrient levels determined by the HMA to those derived from traditional laboratory methods. There was a small but statistically significant difference in the levels of fat, protein, lactose, total solids, and energy for all samples. These differences were consistent with subtle differences in the chemical principles governing the assays. For higher macronutrient levels, a trend to greater differences between the HMA and the laboratory method was seen, particularly in samples with high fat concentration. The intra-assay variation for the HMA for all macronutrients was less than 4%. It is concluded that that with appropriate sample preparation, the mid-infrared HMA can provide a practical measurement of macronutrients in human milk.