Acid Composition Of Human Milk Research Articles

Long chain monomethyl branched-chain fatty acid levels in human milk vary with gestational weight gain

Breastfeeding is an important determinant of infant health and there is immense interest in understanding its metabolite composition so that key beneficial components can be identified. The aim of this research was to measure the fatty acid composition of human milk in an Irish cohort where we examined changes depending on lactation stage and gestational weight gain trajectory. Utilizing a chromatography approach optimal for isomer separation, we identified 44 individual fatty acid species via GCMS and showed that monomethyl branched-chain fatty acids(mmBCFA's), C15:0 and C16:1 are lower in women with excess gestational weight gain versus low gestational weight gain. To further explore the potential contribution of the activity of endogenous metabolic pathways to levels of these fatty acids in milk, we administered D2O to C57BL/6J dams fed a purified lard based high fat diet (HFD) or low-fat diet during gestation and quantified the total and de novo synthesized levels of fatty acids in their milk. We found that de novo synthesis over three days can account for between 10 and 50 % of mmBCFAs in milk from dams on the low-fat diet dependent on the branched-chain fatty acid species. However, HFD fed mice had significantly decreased de novo synthesized fatty acids in milk resulting in lower total mmBCFAs and medium chain fatty acid levels. Overall, our findings highlight the diverse fatty acid composition of human milk and that human milk mmBCFA levels differ between gestational weight gain phenotypes. In addition, our data indicates that de novo synthesis contributes to mmBCFA levels in mice milk and thus may also be a contributory factor to mmBCFA levels in human milk. Given emerging data indicating mmBCFAs may be beneficial components of milk, this study contributes to our knowledge around the phenotypic factors that may impact their levels.

Higher Availability of Long-Chain Monounsaturated Fatty Acids in Preterm than in Full-Term Human Milk.

While the role of n-3 and n-6 long-chain polyunsaturated fatty acids (LCPUFAs) in the maturation of the infantile nervous system is extensively studied and relatively well-characterized, data on the potential developmental importance of the n-9 long-chain monounsaturated fatty acid (LCMUFA), nervonic acid (NA, C24:1n-9) are scarce and ambiguous. Therefore, the aim of the present study was to reanalyze our available data on the contribution of NA and its LCMUFA precursors, gondoic acid (C20:1n-9) and erucic acid (EA, C22:1n-9) to the fatty acid composition of human milk (HM) during the first month of lactation in mothers of both preterm (PT) and full-term (FT) infants. HM samples were obtained daily during the first week of lactation, and then on the 14th, 21st, and 28th days. Values of the LCMUFAs, C20:1n-9, EA, and NA were significantly higher in colostrum than in transient and mature HM. Consequently, there were highly significant inverse associations between LCMUFA values and the duration of lactation. Moreover, C20:1n-9, EA, and NA values were monotonously, considerably, and at many timepoints significantly higher in PT than in FT HM samples. By the 28th day of lactation, summarized LCMUFA values in PT HM samples declined to the level measured in FT HM samples on the first day of lactation; however, EA and NA values were still significantly higher in PT than in FT HM on the 28th day. Significantly higher availability of LCMUFAs in PT than in FT HM underpins the potential biological role of this hitherto somewhat neglected group of fatty acids.

Distribution of Lipid-soluble Vitamin Intake among Exclusively Breastfeeding Mothers and its Correlation with Human Milk’s Fatty Acids

The lipid composition such as fatty acids and fat-soluble vitamins is the second-most abundant composition of human milk providing dietary energy to infants. Micronutrient dietary intake such as vitamin A, D, E, K and C by breastfeeding mothers plays an important role in regulating the quality of human milk for optimum infant health and growth. The objective of this paper is to determine the distribution and correlation of maternal micronutrient intake of lipid-soluble vitamin and vitamin C towards fatty acids composition in human milk of exclusively breastfeeding mothers. A total of N=36 nursing women were recruited from Dengkil, Selangor, and Kuantan, Pahang, using a convenience sample method. A 24-hour dietary recall (24HR) was performed to collect thorough information on all foods and beverages ingested in the previous 24 hours by the respondent. The data on micronutrients intake per mother was tabulated using Nutritionist Pro. (NP) software. Following the diet recall, the human sample was collected in the next morning and subjected to fatty acid extraction and transesterification using the Blight and Dyer method. The composition of fatty acids methyl esters was analyzed and quantified by a gas chromatography (Agilent 7890A), equipped with a flame ionization detector (FID) and Agilent Chromatography Workstation software. The highest mean of intake occurred during the fifth to sixth months with, 1067.37±629.66 µg RE/day for vitamin A, during the first two months with, 0.89±0.84 µg RE/day of vitamin D, 5.85±2.49 mg/day while during the fifth to sixth months with, 17.28±11.74 µg /day of Vitamin E and at the first two months of lactation period with, 91.60±55.26 mg per day for vitamin C. Despite the fact that there was no significant correlation between vitamin intake and the fatty acid content of human milk, the study discovered a variety of patterns of correlation. Saturated fatty acids (SFA) in human milk were only positively correlated with vitamin D and C, while monounsaturated fatty acids (MUFA) were positively correlated with vitamin A, E, and K and negatively correlated with the rest. As a result, the fatty acid composition of human milk is less dependent on micronutrient dietary intake and more dependent on De-Novo synthesis in the mammary gland.

Effects on Maternal Macronutrient Intake Towards Human Milk’s Fatty Acids Composition

While fatty acids found in human milk account for half of the energy consumed by exclusively breastfed infants, fatty acids such as monounsaturated fatty acids (MUFA) and long chain polyunsaturated fatty acids (LC-PUFA) plays critical roles in infant growth. Fatty acids components in human milk are vary widely accordance to the maternal diet during lactation but has not been sufficiently studied. The objective of this paper was to determine the correlation between maternal macronutrient intake with human milk’s fatty acids composition among exclusively breastfeeding mothers. A total of N=36 lactating mothers were recruited based on convenience sampling basis from Dengkil, Selangor and Kuantan, Pahang. A 24-hour dietary recall (24HR) was used to capture mother’s dietary intake in the past 24 hours. The human milk sample was collected in the next day morning after the diet recall and stored before proceeded to another fatty acids extraction and transesterification process namely Blight and Dyer method. The composition of fatty acids methyl esters was analyzed and quantified by a gas chromatography (Agilent 7890A), equipped with a flame ionization detector (FID) and Agilent Chromatography Workstation software. As overall, the most abundance fatty acids found was SFA ranged (81.90 to 97.7 %) followed with MUFA (2.3 to 18.1%), but PUFA was below detection limit (BDL). Result also indicated that palmitic, stearic, and oleic acids were the three major types of fatty acids determined from human milk. Correlational study also determined that, there was no significant correlation between the human milk’s SFA and MUFA with the same dietary intake and another macronutrient like carbohydrate and protein. Even though there was no significant correlation determined for the most composition, various pattern of correlation was found in the study. Human milk’s SFA only had a positive correlation with dietary carbohydrate but negative with the rest. Different pattern also showed for human milk’s MUFA which only negatively correlate with carbohydrate and fats while positive for the rest. Thus, overall, this fat composition is known to have higher variation in terms of concentration of its components compared to another macronutrient even within the same population. Aside from geographical considerations, maternal nationality and age have a substantial impact on the fatty acid composition of human milk.

Investigation of Maternal Diet and FADS1 Polymorphism Associated with Long-Chain Polyunsaturated Fatty Acid Compositions in Human Milk.

Increasing the amount of long-chain polyunsaturated fatty acids (LCPUFA) in human milk is an important strategy for infant growth and development. We investigated the associations of LCPUFA compositions in human milk with maternal diet (especially fish and shellfish intake), with fatty acid Δ5 desaturase gene (FADS1) polymorphisms, and with gene-diet interactions. The present study was performed as part of an adjunct study of the Japan Environment and Children’s Study. The participants were 304 lactating females, who provided human milk 6–7 months after delivery. Fatty acids in human milk were analyzed by gas chromatography, and dietary surveys were conducted using a brief self-administered diet history questionnaire. We also analyzed a single nucleotide polymorphism of FADS1 (rs174547, T/C). There was a significant difference in arachidonic acid (ARA) composition in human milk among the genotype groups, and the values were decreasing in the order of TT > TC > CC. The concentrations of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) were also different between TT and CC genotype, indicating a tendency for decreasing values in the same order. The composition of ARA showed significant gene–dietary interactions in multiple regression analysis, and the positive correlation between fish and shellfish intake and ARA composition in human milk was significant only in the CC genotype. Moreover, the factor most strongly associated with EPA and DHA composition in human milk was fish and shellfish intake. Therefore, it was suggested that increasing fish and shellfish intake in mothers may increase EPA and DHA composition in human milk, while increasing fish and shellfish intake in CC genotype mothers may lead to increased ARA composition in human milk.

Fatty Acid Determination in Human Milk Using Attenuated Total Reflection Infrared Spectroscopy and Solvent-Free Lipid Separation.

This study introduces the first mid-infrared (IR)-based method for determining the fatty acid composition of human milk. A representative milk lipid fraction was obtained by applying a rapid and solvent-free two-step centrifugation method. Attenuated total reflection Fourier transform infrared (ATR FT-IR) spectroscopy was applied to record absorbance spectra of pure milk fat. The obtained spectra were compared to whole human milk transmission spectra, revealing the significantly higher degree of fatty acid-related spectral features in ATR FT-IR spectra. Partial least squares (PLS)-based multivariate regression equations were established by relating ATR FT-IR spectra to fatty acid reference concentrations, obtained with gas chromatography-mass spectrometry (GC-MS). Good predictions were achieved for the most important fatty acid sum parameters: saturated fatty acids (SAT, R2CV = 0.94), monounsaturated fatty acids (MONO, R2CV = 0.85), polyunsaturated fatty acids (PUFA, R2CV = 0.87), unsaturated fatty acids (UNSAT, R2CV = 0.91), short-chain fatty acids (SCFA, R2CV = 0.79), medium-chain fatty acids (MCFA, R2CV = 0.97), and long-chain fatty acids (LCFA, R2CV = 0.88). The PLS selectivity ratio (SR) was calculated in order to optimize and verify each individual calibration model. All mid-IR regions with high SR could be assigned to absorbances from fatty acids, indicating high validity of the obtained models.

Trans Fatty Acids in Human Milk in Latvia: Association with Dietary Habits during the Lactation Period.

The human milk fatty acid, including trans fatty acid, composition is predominantly affected by the maternal diet. The aim of this research was to determine the trans fatty acid level in human milk among lactating women in Latvia, and to evaluate how maternal dietary habits affect the trans fatty acid composition of human milk. In total, 70 lactating women participated in this cross-sectional study. A 72-hour food diary and food frequency questionnaire were used to evaluate maternal dietary habits. Different trans fatty acids in human milk samples were determined using gas chromatography (Agilent 6890N, Agilent Technologies Incorporated, the United States). Overall, the dietary intake of trans fatty acids among the participants was 0.54 ± 0.79 g per day. The total trans fatty acid level in the human milk samples was 2.30% ± 0.60%. The composition of trans fatty acids found in human milk was associated with maternal dietary habits. Higher elaidic acid, vaccenic acid and total trans fatty acid levels in human milk were found among participants with a higher milk and dairy product intake. Meat and meat product intake were associated with a higher vaccenic acid and total trans fatty acid levels in human milk. A moderate association was also established between maternal trans fatty acid intake and the total trans fatty acid level in human milk. The obtained correlations indicate that maternal dietary habits during lactation can impact the composition of trans fatty acids found in human milk.

Comparative Lipidomics Analysis of Human Milk and Infant Formulas Using UHPLC-Q-TOF-MS.

The lipidome and fatty acid composition of human milk and different infant formulas with animal- and/or plant-based fat sources are analyzed and compared in this study. The results obtained using positive and negative ionization modes indicate that there are 48 and 71 lipid species, respectively, that are common between the human milk and infant formulas. Moreover, the fatty acid composition in infant formulas varies significantly, depending on the fat source. Human milk is rich in triacylglycerols that contain linoleic acid, α-linolenic acid, arachidonic acid, and docosahexaenoic acid. Meanwhile, the triacylglycerols in IFB comprise long-chain fatty acids at the sn-1,3 position. Compared to human milk, IFC has the same level of sphingomyelin species. Based on univariate and multivariate analyses, there are 37, 34, 31, and 36 lipid species that can be used to distinguish between human milk and infant formulas. Overall, the results reported herein are useful in designing new milk formulas that better mimic human milk.

Interactions between cortisol and lipids in human milk

BackgroundHuman breast milk is one of the key early postnatal biological exposures for the developing child. It includes bioactive compounds, such as cortisol and fatty acids, which may be linked via the mother’s lipid metabolism.MethodsThis study investigated the associations between cortisol and lipids in human milk at the infant age of 2.5 months. Human milk cortisol concentrations were measured using luminescence immunoassay, and two groups of milks (n = 50 each) were formed based on either high (> 10 nmol/L) or low (< 3 nmol/L) cortisol levels. Lipids, as fatty acid content and composition of neutral (triacylglycerol-rich) and polar (phospholipid-rich) lipids, were measured with gas chromatography. The samples originated from the FinnBrain Birth Cohort Study.ResultsThe percentage of phospholipid-rich lipids of total lipids was 33.08% ± 1.33%. In triacylglycerol-rich lipids, high cortisol level in milk was associated with higher lauric (12:0, mass % and mg/mL), myristic (14:0, mass % and mg/mL), eicosenoic (20:1n − 9, mass %), docosenoic (22:1n − 9, mass %, and mg/mL) acids, and to lower palmitic acid (16:0, mass %) compared with low cortisol levels in milk. In phospholipid-rich lipids, high cortisol level was associated with higher myristic (14:0, mass %) and docosenoic (22:1n − 9, mass %) acids. After adjusting for pre-pregnancy BMI and sampling time by linear regression, the milk cortisol remained a significant predictor for lauric and myristic acids in triacylglycerol-rich lipids, and myristic and docosenoic acid in phospholipid-rich lipids (β = 0.23 to 0.38 and p < 0.05 for each).ConclusionsThis study revealed certain significant associations between milk cortisol and the fatty acid composition of human milk, indicating that cortisol might be one of the factors affecting the origin of the lipids in human milk.

Short-term effects of dietary bovine milk on fatty acid composition of human milk: A preliminary multi-analytical study

The fatty acid (FA) composition of human milk (HM) from N = 9 Italian healthy donors following a free diet exhibited FA-dependent ranges of variability, as assessed by GC-FID. The possible short-term changes in the FA profile were monitored in the milk of lactating mothers (three) collected at five time points over a 6 h period, following an oral load (200 mL) of bovine milk. An array of techniques was exploited, including UHPLC-ESI-MS/MS of intact lipids and MALDI-TOF MS before and after chemical hydrogenation or bromination, in addition to MALDI-TOF MS analysis of FA after saponification, to monitor short-chain and odd-chain FA in HM as markers of bovine milk fat.A single administration of bovine milk did not appreciably modify the lipid pattern, suggesting that the maternal diet could induce not detectable short-term changes on the lipid composition of HM. Diet-induced increase of butyric acid was also excluded by 13C NMR.The functions that HM FA exert in infant physiology appear finely regulated through maternal metabolism.

Effect of lactation stages and dietary intake on the fatty acid composition of human milk (A study in northeast China)

The correlation among lactation stages (until 30 days), lactation dietary intake and fatty acid (FA) composition in human milk (n = 202) was evaluated. The total saturated fatty acids (SFAs) and total monounsaturated fatty acids (MUFAs) remained stable over lactation progression, but medium-chain SFAs increased during the lactation stages. The n-6 polyunsaturated fatty acids were in highest concentrations in mature milk owing to the highest levels of C18:3n-6 and C18:2n-6 (0.18% and 46.06% respectively). Linoleic acid and α-linolenic acid (ALA) intakes were within the recommended levels. Linear regression analysis indicated that the intake of soybean oil and dietary ALA intake affected the n-6 PUFA content in colostrum and transitional milk positively. The effect of dietary intake on FA composition in human milk decreased during the first 30 days and nutritional regulation in the early stage of lactation should be highlighted.

Selected elements and fatty acid composition in human milk as indicators of seafood dietary habits

The maternal diet and living environment can affect levels of chemical elements and fatty acid (FA) composition and their stable isotopes (δ13CFA) in human milk. Information obtained from questionnaires is frequently imprecise, thus limiting proper associations between external and internal exposures as well as health effects. In this study, we focused on seafood as a source of potentially toxic and essential elements and nutritional FAs. Concentrations of selected elements in human milk (As, Cd, Cu, Mn, Pb, Se and Zn) were determined using inductively coupled plasma mass spectrometry (ICP-MS) and Hg using cold vapour atomic-absorption spectrometry (CV-AAS). The identification and quantification of FAs in maternal milk were performed by an in-situ trans-esterification method (FAMEs), and the characterization of FAMEs was performed by gas chromatography with a flame ionisation detector (GC-FID). δ13CFA was determined by gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS). Seventy-four lactating Slovenian women from the coastal area of Koper (KP), with more frequent consumption of seafood, and the inland area of Pomurje (MS), with less frequent seafood consumption, were included in this study. Along with basic statistical analyses, data mining approaches (classification and clustering) were applied to investigate whether FA composition and δ13CFA could improve the information regarding dietary sources of potentially toxic elements. As and Hg levels in milk were found to be statistically higher in populations from KP than in those from MS, and 71% of individual FAs and 30% of individual δ13CFA values in milk differed statistically between the studied areas. In 19 cases, the levels of FAs in milk were higher in KP than in MS; these FAs include C20:5ω3 and C22:6ω3/C24:1ω9, which are typically contained in fish. In 16 cases, the mean percentage of FAs was higher in MS than in KP; these FAs include the PUFAs C18:2ω6, C18:3ω3, and C20:4ω6 which are important for human and infant growth. The difference in δ13C levels of C10:0, C12:0, C14:0, C16:1, C16:0, C18:1ω9c, C22:6ω3, and δ13C 18:0–16:0 in the study groups was statistically significant. In all seven cases where δ13C of FA significantly differed between KP and MS, δ13C was higher in KP, indicating a higher proportion of a marine-based diet. The data mining approaches confirmed that the percentage of selected FAs (iC17:0, C4:0, C18:2ω6t, aC17:0, CLA, and C22:4ω6) and δ13CFA of C18:1ω9c in human milk could be used to distinguish between high and low frequency of fresh seafood consumption.

Fatty acid composition of breast milk in Galicia (NW Spain): A cross-country comparison

Based on the premise that the fatty acid composition of human milk can be substantially altered by diet, the current study investigated the fatty acid profile (fattyacidome) of breast milk in Galicia, a small region located in the north-west of Spain and characterized by the Southern European Atlantic Diet (SEAD). A cross-country comparison was also performed to assess worldwide variety and diet impact, reviewing the profiles reported various European, North and South American, Asian and African countries and Australia. Galician human milk appeared similar to the rest of Europe, with some particular features related to the SEAD (dairy, pork, beef and sunflower and olive oils), such as relatively high levels of linoleic acid and lower α-linolenic acid. The results also showed the existence of woman-specific profiles and significant changes over lactation in some fatty acids. Worldwide, the fatty acid profiles were similar, with the clear exception of Asiatic breast milk. The impact of fatty acids on infant health warrants further investigation.

Changes in Fatty Acid Composition of Human Milk in Response to Cold-Like Symptoms in the Lactating Mother and Infant.

Infants rely on their innate immune systems to protect them from infection. Human milk (HM) contains fatty acids (FAs) and monoacylglycerols that are known to exhibit antiviral and antibacterial properties in vitro. The specific fat content of HM may potentially affect the efficacy of this antimicrobial activity. This preliminary study investigates whether the proportions of FA in HM change in response to infections, leading to cold-like symptoms in the mother or infant. Milk samples were obtained from mothers (n = 26) when they and their infants were healthy, and when mother, infant, or both suffered cold-like symptoms. The milk was hydrolysed and FA proportions were measured using gas chromatography. Fifteen FAs were recorded, of which eight were detected in sufficient quantities for statistical analysis. The proportions of capric (C10:0) and lauric acids (C12:0) in HM were significantly lower, and palmitic acid (C16:0) was higher when mothers and infants were ill compared to healthy samples. Palmitoleic (C16:1, n-7) and stearic acid (C18:0) proportions were higher in HM when the infant was unwell, but were not related to maternal health. Whilst the differences detected were small (less than 0.5%), the effects may be additive and potentially have a protective function. The value of further studies is certainly indicated.

Genomics of lactation: role of nutrigenomics and nutrigenetics in the fatty acid composition of human milk.

Human milk covers the infant's nutrient requirements during the first 6 months of life. The composition of human milk progressively changes during lactation and it is influenced by maternal nutritional factors. Nowadays, it is well known that nutrients have the ability to interact with genes and modulate molecular mechanisms impacting physiological functions. This has led to a growing interest among researchers in exploring nutrition at a molecular level and to the development of two fields of study: nutrigenomics, which evaluates the influence of nutrients on gene expression, and nutrigenetics, which evaluates the heterogeneous individual response to nutrients due to genetic variation. Fatty acids are one of the nutrients most studied in relation to lactation given their biologically important roles during early postnatal life. Fatty acids modulate transcription factors involved in the regulation of lipid metabolism, which in turn causes a variation in the proportion of lipids in milk. This review focuses on understanding, on the one hand, the gene transcription mechanisms activated by maternal dietary fatty acids and, on the other hand, the interaction between dietary fatty acids and genetic variation in genes involved in lipid metabolism. Both of these mechanisms affect the fatty acid composition of human milk.

Changes in fatty acid composition of human milk in response to cold-like symptoms in the lactating mother and infant

Changes in fatty acid composition of human milk in response to cold-like symptoms in the lactating mother and infant

Are There Changes in the Fatty Acid Profile of Breast Milk with Supplementation of Omega-3 Sources? A Systematic Review.

Purpose To evaluate the effect of supplementation with omega-3 sources on the fatty acid composition of human milk. Methods The review consisted of the search for articles published in PubMed, Biblioteca Virtual de Saúde (Virtual Health Library[VHL]) and Web of Science databases using the following keywords: fatty acids, omega-3, human milk and supplementation; for this purpose, we have used the program of research to integrate the services for the maintenance of autonomy (PRISMA) checklist. The following selection criteria were used: articles in English, Portuguese, Spanish or Italian, published between 2000 and 2015, and about studies performed in humans. We found 710 articles that met the established criteria; however, only 22 of them were selected to be part of this study. Results All studies found a positive relationship between the consumption of omega-3 sources and their concentration in human milk. The differences in the findings are due to the distinct methods used, such as the specific time of the omega-3 supplementation, the type of omega-3 source offered, as well as the sample size. Conclusion Although the studies were different in several methodological aspects, it was possible to observe the importance of omega-3 supplementation during gestation and/or the puerperium.

Branched-chain fatty acid composition of human milk and the impact of maternal diet: the Global Exploration of Human Milk (GEHM) Study

Background: An understudied component of the diet, branched-chain fatty acids (BCFAs) are distinctive saturated fatty acids that may have an important influence on health. Human-milk fatty acid composition is known to differ worldwide, but comparative data are lacking on BCFAs.Objective: We tested the hypotheses that concentrations of BCFAs in human milk differ between populations and are associated with maternal diet.Design: We surveyed the BCFA composition of samples collected as part of a standardized, prospective study of human-milk composition. Mothers were enrolled from 3 urban populations with differing diets: Cincinnati, Ohio; Shanghai, China; and Mexico City, Mexico. Enrollment was limited to healthy mothers of term singleton infants. We undertook a cross-sectional analysis of milk from all women with samples at postpartum week 4 (n = 359; ∼120 women/site). Fatty acids were extracted from milk by using a modified Bligh-Dyer technique and analyzed by gas chromatography. Statistical analysis was performed by ANOVA and Tobit regression. For Cincinnati mothers, 24-h diet recalls were analyzed in relation to the individual BCFA concentrations measured in milk samples.Results: Total BCFAs in milk differed by site, with the highest concentration in Cincinnati followed by Mexico City and Shanghai (mean ± SE: 7.90 ± 0.41, 6.10 ± 0.36, and 4.27 ± 0.25 mg/100 mL, respectively; P < 0.001). Site differences persisted after delivery mode, maternal age, and body mass index were controlled for. The individual concentrations of iso-14:0, iso-16:0, iso-18:0, anteiso-15:0, and anteiso-17:0 also differed between sites. Milk concentrations of iso-14:0 and anteiso-15:0 were associated with maternal intake of dairy; iso-16:0 was associated with maternal intakes of dairy and beef.Conclusions: BCFA concentrations in milk at 4 wk postpartum differed between mothers from Cincinnati, Shanghai, and Mexico City. Variations in human-milk BCFAs are influenced by diet. The impact of BCFAs on infant health warrants investigation.

Differences in the Infant Gut Microbiota Related to the Fatty Acid Composition of Human Milk: Results from the GEHM Cohort

BackgroundThe fatty acid (FA) composition of human milk varies between mothers, influenced by maternal diet. Available evidence suggests a potential influence of dietary FA on the composition of the gut microbiota, but the impact of dietary FAs on gut microbiota are not well characterized, particularly in breastfed infants.ObjectiveWe conducted a pilot study to assess the impact of variation in human milk FA composition on the infant gut microbiota.MethodsHuman milk and infant stool samples were collected at 4 weeks postpartum from 32 mother‐infant pairs; infants were healthy, term singletons. Human milk FAs were measured by a modified Bligh‐Dyer technique and analyzed by gas chromatography. Stool DNA was extracted using a QiaGen kit with bead beating, and the 16s rRNA gene sequenced by Illumina MiSeq. Using weighted UniFrac, non‐metric multidimensional scaling, and ordisurf in QIIME and R, we tested for associations between the infant gut microbiome and 27 different FAs of human milk, presented as both concentration of individual FAs and as proportion of total FA.ResultsHuman milk octadecanoic acid (18:0: common name, stearic acid) concentration and proportion of total FA was associated with the composition of the infant stool microbial community after adjusting for multiple comparisons (p=0.0002 and p=0.0014). The combination of oleic acid and cis‐vaccenic acid (C18:1n9 plus C18:1n7), when analyzed as a proportion of total fatty acid, was also significantly associated with the composition of the infant stool microbiome (p&lt;0.0001). Streptococcus anginosus was more abundant in infants fed milk with lower levels of stearic acid, while Bacillales, Staphylococcaceae, and Staphylococcus levels were higher in infants fed milk with higher levels of stearic acid. Bifidobacteriales, Bifidobacteriaceae, and Bifidobacterium were more abundant in infants fed milk with lower levels of oleic acid and cis‐vaccenic acid, while Actinomycetaceae and Actinomyces were more abundant in infants fed milk with higher levels of oleic acid and cis‐vaccenic acid. Analysis of maternal diet and human milk FA composition is underway.ConclusionsThis pilot project provides initial evidence that variation in the FAs of human milk is associated with differences in infant gut microbiota. Larger studies are needed to test for differences in the microbiota associated with FA.Support or Funding InformationSupported by Mead Johnson Pediatric Nutrition Institute (MJPNI; research contract (#3140)); NICHD P01 HD13021

A nine-country study of the protein content and amino acid composition of mature human milk

BackgroundNumerous studies have evaluated protein and amino acid levels in human milk. However, research in this area has been limited by small sample sizes and study populations with little ethnic or racial diversity.ObjectiveEvaluate the protein and amino acid composition of mature (≥30 days) human milk samples collected from a large, multinational study using highly standardized methods for sample collection, storage, and analysis.DesignUsing a single, centralized laboratory, human milk samples from 220 women (30–188 days postpartum) from nine countries were analyzed for amino acid composition using Waters AccQ-Tag high-performance liquid chromatography and total nitrogen content using the LECO FP-528 nitrogen analyzer. Total protein was calculated as total nitrogen×6.25. True protein, which includes protein, free amino acids, and peptides, was calculated from the total amino acids.ResultsMean total protein from individual countries (standard deviation [SD]) ranged from 1,133 (125.5) to 1,366 (341.4) mg/dL; the mean across all countries (SD) was 1,192 (200.9) mg/dL. Total protein, true protein, and amino acid composition were not significantly different across countries except Chile, which had higher total and true protein. Amino acid profiles (percent of total amino acids) did not differ across countries. Total and true protein concentrations and 16 of 18 amino acid concentrations declined with the stage of lactation.ConclusionsTotal protein, true protein, and individual amino acid concentrations in human milk steadily decline from 30 to 151 days of lactation, and are significantly higher in the second month of lactation compared with the following 4 months. There is a high level of consistency in the protein content and amino acid composition of human milk across geographic locations. The size and diversity of the study population and highly standardized procedures for the collection, storage, and analysis of human milk support the validity and broad application of these findings.