Fatty acid composition of milk of refugee Karen and urban Korean mothers. Is the level of DHA in breast milk of Western women compromised by high intake of saturated fat and linoleic acid?

Optimizing ARA and DHA in infant formula: A systematic review of global trends, regional disparities, and considerations for precision nutrition

In the context of precision nutrition, the addition of ARA and DHA in infant formula needs to consider more factors. This study conducted a comprehensive literature review, including 112 relevant Chinese and English articles, to summarize and analyze the global levels of ARA, DHA, and the ARA/DHA ratio in breast milk. The data were correlated with local aquatic products intake and children's IQ. The results indicated that the average level of DHA in breast milk across regions is lower than that of ARA. Variations in DHA content were identified as a primary factor influencing ARA/DHA ratio fluctuations. Breast milk ARA and DHA levels decrease with prolonged lactation periods but increase over the past 22 years. Correlation analysis revealed a significant positive relationship between aquatic products intake and breast milk DHA levels (r = 0.64, p < 0.05). Breast milk DHA levels also showed a significant positive correlation with children's IQ (r = 0.67, p < 0.01). Stable breast milk ARA content did not exhibit significant correlations with aquatic products intake or children's IQ (r = 0, p > 0.05). Among 22 infant formula products available in China, only 5 had ARA levels within the range of breast milk. Most formula products had higher ARA levels than DHA, resulting in ARA/DHA ratios generally exceeding 1. The temporal and spatial variability in breast milk ARA and DHA levels may lead to diverse health outcomes in infants. Therefore, the addition of ARA and DHA in infant formula should consider this variability, including the molecular forms and positional isomerism of the added ARA and DHA. Additionally, considering the impact of different cognitive development tests and infant's gene expression on formula assessment results, there is a need to establish a more comprehensive infant health assessment system to guide the addition of ARA and DHA in formula.

Quantitative Analysis of Nervonic and Erucic Acids in Human Milk: Comparison with Infant Formula with Different Fat Sources and Nutritional Stages

This study aims to quantitatively analyze nervonic (C24:1 n-9) and erucic (C22:1 n-9) acids in human milk (HM) collected from Korean mothers, along with the infant formulas (IFs) with different fat sources and nutritional stages. The content of nervonic and erucic acids in HM from Korean mothers were 2.13 and 2.81 mg/100 g, accounting for 0.06 and 0.08% of the total fatty acids (FAs), respectively. These acids in IFs based on fat from plant-oil formula were higher than those in IFs based on cow milk formula. The composition of erucic acid in IFs based on cow milk formula and plant-oil formula increased with the nutritional stages, while nervonic acid only increased in IFs based on the plant-oil formula.

The imperative of arachidonic acid in early human development

This review is about the role of arachidonic acid (ArA) in foetal and early growth and development. In 1975 and '76, we reported the preferential incorporation of ArA into the developing brain of rat pups, its conservation as a principal component in the brains of 32 mammalian species and the high proportion delivered by the human placenta for foetal nutrition, compared to its parent linoleic acid (LA). ArA is quantitatively the principal acyl component of membrane lipids from foetal red cells, mononuclear cells, astrocytes, endothelium, and placenta. Functionally, we present evidence that ArA, but not DHA, relaxes the foetal mesenteric arteries. The placenta biomagnifies ArA, doubling the proportion of the maternal level in cord blood. The proportions of ArA and its allies (di-homo-gamma-linolenic acid (DGLA), adrenic acid and ω6 docosapentaenoic acid) are similar or higher than the total of ω3 fatty acids in human milk, maintaining the abundant supply to the developing infant. Despite the evidence of the importance of ArA, the European Food Standard Agency, in 2014 rejected the joint FAO and WHO recommendation on the inclusion of ArA in infant formula, although they recommended DHA. The almost universal dominance of ArA in the membrane phosphoglycerides during human organogenesis and prenatal growth suggests that the importance of ArA and its allies in reproductive biology needs to be re-evaluated urgently.

Human Milk Lipid Profiles around the World: A Systematic Review and Meta-Analysis

Reported breast milk lipid concentrations may vary with geographical region, postnatal age, and year of sample collection. In this review, we summarized data on the concentrations of total fat, total phospholipids, cholesterol, and fatty acids in human milk worldwide and their variation according to lactation stage, study area, and sample collection year. A systematic literature search was performed using the PubMed, Embase, Web of Science, and Medline databases for English-language papers and Wanfang and China National Knowledge Infrastructure databases for Chinese-language papers. A total of 186 studies evaluating the human milk lipid profiles were included. According to random-effects models based on worldwide data, the summarized means (95% CIs) as percentages of total fat were 42.2% (41.1%, 43.3%) for SFAs, 36.6% (35.6%, 37.5%) for MUFAs, and 21.0% (19.3%, 22.7%) for PUFAs. However, the study heterogeneity was high for most types of fatty acids (I2 > 99%). Human milk from Western countries had higher concentrations of MUFAs and 18:1n-9 (ω-9), but lower concentrations of PUFAs, 18:2n-6, 20:4n-6, 18:3n-3, 20:5n-3, 22:6n-3, and total n-6 PUFA compared with those from non-Western countries (P < 0.001-0.011). Significant lactation stage differences were observed for total fat and some individual fatty acids. The concentrations of SFAs and 16:0 were significantly negatively correlated with sampling year (P < 0.001-0.028). In contrast, a significant positive correlation between the concentrations of 18:2n-6 and 18:3n-3 and sampling year was observed (P < 0.001-0.035). Our results suggest that the pooling of data on human milk lipid profiles in different studies should be done with caution due to the high between-study heterogeneity. The concentration of lipids, including total fat, cholesterol, and specific fatty acids, differs in human milk according to lactation stage, geographical region, and year of sample collection.

Comparison of the Macronutrient Content of Colostrum: Locals with Refugees

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

Human milk fatty acid profile across lactational stages after term and preterm delivery: A pooled data analysis

BACKGROUND

Lipids in human milk (HM) provide the majority of energy for developing infants, as well as crucial essential fatty acids (FA). The FA composition of HM is highly variable and influenced by multiple factors. We sought to increase understanding of the variation in HMFA profiles and their development over the course of lactation, and after term and preterm delivery, using a pooled data analysis.

OBJECTIVE

To review the literature and perform a pooled data analysis to qualitatively describe an extensive FA profile (36 FAs) in term and preterm colostrum, transitional - and mature milk up to 60 days postpartum.

DESIGN

A Medline search was conducted for HMFA profile data following term or preterm delivery. The search was confined to English language papers published between January 1980 and August 2018. Studies reporting original data, extensive FA profiles in HM from healthy mothers were included. Weighted least squares (WLS) means were calculated from the pooled data using random or fixed effect models.

RESULTS

Our pooled data analysis included data from 55 studies worldwide, for a total of 4374 term milk samples and 1017 preterm milk samples, providing WLS means for 36 FAs. Patterns in both term and preterm milk were apparent throughout lactation for some FAs: The most abundant FAs (palmitic, linoleic and oleic acid) remained stable over time, whereas several long-chain polyunsaturated FAs (including ARA and DHA) seemed to decrease and short- and medium-chain FAs increased over time.

CONCLUSIONS

High heterogeneity between individual studies was observed for the reported levels of some FAs, whereas other FAs were remarkably consistent between studies. Our pooled data suggests that specific FA categories fluctuate according to distinct patterns over the course of lactation; many of these patterns are comparable between term and preterm milk.

Fatty acids of human milk - a review

The composition of human milk is the result of the evolution of mammals over millions of years. Among the most important components of milk are fatty acids. Approximately 85% are saturated and monounsaturated fatty acids - the rest are polyunsaturated one. Their role is to provide energy and immunity and to serve as buildings blocks, as well as assisting the hormonal system and the metabolism of fats, carbohydrates and proteins. The structural differences between fatty acids determine their biodiversity and give them particular physiological importance. Correct development of the nervous system, retina and other structures depend on an adequate supply of both these fatty acids during intrauterine development and in the newborn and infant stages. The fats present in milk form milk fat globules - structures that do not appear in milk formula prepared using vegetable oils. Apart from the mother's diet, other sources of fatty acids are endogenous biosynthesis in the mammary gland and the fat deposits from which the fatty acids are released. Evolution of the mother's body has also created adaptive mechanisms that adjust the amount of fatty acids in milk to the state of health and needs of the child. These mechanisms go some way to creating a buffer with regard to dietary shortages experienced by pregnant/breastfeeding women, and optimalise the composition of milk fatty acids depending on the age of the pregnant woman, the birth weight of the infant and the efficiency of the placenta during pregnancy.

Is fatty acid composition of breast milk different in various populations? A systematic review and meta-analysis

This systematic review and meta-analysis aims to systematically review the fatty acid (FA) composition of breast milk in different populations. We systematically searched the Medline via PubMed, Scopus and Clarivate till July 2019. We initially retrieved 433 articles. Having removed duplicates, with initial searching of title and abstracts, 317 papers were excluded and 80 remained. A meta-analysis of 80 cross-sectional, cohort studies, including 8793 subjects, was conducted. Meta-regression analysis indicated that factors including maternal age (p-values of SFA: 0.03, omega-3: 0.01, trans fats:<0.001, total fatty acids: 0.02), year of conducting study (p-values of SFA: <0.001, MUFA: 0.02, omega-6: 0.04,trans fats: 0.04) and sample size (p-values of SFA: 0.03, PUFA: 0.01, omega-6: 0.01, omega-3:<0.001) contributed to the heterogeneity of meta-analysis. This study indicates the large variation of FA content in maternal milk across different populations. Special concern is necessary for both the quality and total amount of fat intake of pregnant and lactating mothers.

Quantification of Nervonic Acid in Human Milk in the First 30 Days of Lactation: Influence of Lactation Stages and Comparison with Infant Formulae

Nervonic acid (24:1 n-9, NA) plays a crucial role in the development of white matter, and it occurs naturally in human milk. This study aims to quantify NA in human milk at different lactation stages and compare it with the NA measured in infant formulae. With this information, optimal nutritional interventions for infants, especially newborns, can be determined. In this study, an absolute detection method that uses experimentally derived standard curves and methyl tricosanoate as the internal standard was developed to quantitively analyze NA concentration. The method was applied to the analysis of 224 human milk samples, which were collected over a period of 3–30 days postpartum from eight healthy Chinese mothers. The results show that the NA concentration was highest in colostrum (0.76 ± 0.23 mg/g fat) and significantly decreased (p < 0.001) in mature milk (0.20 ± 0.03 mg/g fat). During the first 10 days of lactation, the change in NA concentration was the most pronounced, decreasing by about 65%. Next, the NA contents in 181 commercial infant formulae from the Chinese market were compared. The NA content in most formulae was <16% of that found in colostrum and less than that found in mature human milk (p < 0.05). No significant difference (p > 0.05) was observed among NA content in formulae with different fat sources. Special attention was given to the variety of n-9 fatty acids in human milk during lactation, and the results indicated that interindividual variation in NA content may be primarily due to endogenous factors, with less influence from the maternal diet.

Positive relationship between consumption of specific fish type and n-3 PUFA in milk of Hong Kong lactating mothers

Residents of Hong Kong have undergone a dietary transition from a traditional Chinese diet that is high in seafood to a more Western diet. This may have affected the nutritional composition of breast milk of Hong Kong mothers. The present study aims to investigate the relationship between the dietary pattern and the fatty acid profile of the breast milk of lactating women in Hong Kong. Seventy-three volunteering healthy Hong Kong lactating mothers participated in the study. Their dietary intakes were assessed by using a 3-d dietary record and FFQ. The mean n-3 fatty acid levels were approximately 0·4 % (EPA) and 0·9 % (DHA) of total fatty acids in the breast milk of lactating mothers who had exclusively breastfed their infants aged 2-6 months. Maternal dietary intakes of n-3 fatty acids were positively associated with their levels in the breast milk. The levels of maternal intakes of freshwater and saltwater fish, especially the consumption of salmon, croaker and mandarin, were significantly correlated with the content of DHA in breast milk. The present study is among the very few in the literature to determine the fatty acid profile of breast milk in Hong Kong populations and verify certain dietary factors that influence this profile. High levels of n-3 PUFA, especially DHA, were observed in the breast milk of Hong Kong lactating women. The findings may serve as a dietary reference for lactating mothers to optimise the fatty acid profile of their breast milk.

Breast milk fatty acid composition and fatty acid intake of lactating mothers in South Korea

The aim of this study was to determine the fatty acid (FA) composition of breast milk, and its association with mothers' FA intake. Milk samples were obtained from 238 healthy lactating women who volunteered to participate in the Human Milk Micronutrients Analysis Research. Dietary intake during lactation was assessed using a 3-d food record, and fat content and FA composition of the breast milk samples were analysed by IR spectrometry using MilkoScan FT2 and GC flame ionisation detector, respectively. The fat content was 3·31 (sd 1·41) g/100 ml breast milk. The concentrations of arachidonic acid (20 : 4 n-6), EPA (20 : 5 n-3) and DHA (22 : 6 n-3) in breast milk were 0·48 (sd 0·13), 0·15 (sd 0·12) and 0·67 (sd 0·47) % of total FA, respectively. Fat content and FA composition of breast milk were associated with maternal age, BMI, supplement use and infant age. Dietary intakes of EPA, DHA, n-3 FA, n-6 FA, SFA and PUFA were positively correlated with the corresponding FA in the milk samples. FA levels in breast milk and maternal diet are highly correlated. Further studies are warranted to explore factors that may be associated with changes in FA composition in human milk.