Acid Composition Of Human Milk Research Articles

160 Fatty Acid Composition of Human Milk in a Portuguese Urban Population:Prospective Study from 7 Days to 16 Weeks of Lactation

Fat in human milk varies during a feed, during the day and throughout the period of lactation. Fatty acid (FA) composition varies over the course of the day and during lactation. Aim: To evaluate FA composition in human milk, from 7 days (transitional milk) to 16 weeks of lactation (mature milk) and to assess the composition stability of these FA throughout this period. Methods: Mothers living in urban area of Porto who accepted to participate in the study were selected according to inclusion criteria (healthy term newborn exclusively breast-feeding). Pooled human milk was collected from all feedings over 24 hours at the following times: 7 days and 4, 8, 12 and 16 weeks of lactation. FA were analysed through capillary gas chromatography. Comparisons were made (Oneway ANOVA). Correlations between FA were made through Pearson and Spearman correlation coefficient. Results: 31 mothers completed the follow-up period. Total saturated fatty acids (SFA) progressively increased from 40.50 ± 3.72 (% wt/wt) at 7th day up to 43.08 ± 4.61 at the 16th week of lactation, whereas total monounsaturated fatty acid decreased from 33.04 ± 2.58 (% wt/wt) to 31.48 ± 3.32, in the same period. Arachidonic acid (AA) markedly decreases with the stage of lactation. Docosahexaenoic acid (DHA) content decreases lightly from the 7th day to the 4th week of lactation, remaining stable throughout the rest of the lactation period. No significant correlation was found between the levels of linonleic and a-linolenic acid, and their long-chain metabolites AA and DHA. Conclusions: Despite fluctuations in the contents of AA and DHA, the ratio AA/DHA did not significantly change throughout the period of lactation. The ratio AA/DHA remained constant during the study, suggesting a protective mechanism, as AA and DHA are essential structural components of all tissues and particularly of retina and neuronal tissues.

5 Polyunsaturated Fatty Acids in Argentinian Human Milk: Is There a Relative Deficiency in N-3 Fatty Acids?

Background: Human milk fat is the main source of energy for breastfed infants. Milk fat also transports lipid soluble vitamins and n-6 and n-3 polyunsaturated fatty acids (PUFAs), essential for the proper development of the brain, retina, and other organs. Fatty acids are the only milk lipids that can be altered to any extend by maternal dietary manipulation. Since maternal nutritional status during pregnancy is critical for the newborn, and little information exists regarding the PUFA status of populations living in Southern regions, Objective: To study the relationship between maternal nutrition and the fatty acid composition of human milk. Methods: Milk samples were obtained from mothers of normal nursing infants born at full term; maternal nutritional state was assessed using the body mass index. On this basis, mothers were considered as normal, overweight or obese. Maternal diet was evaluated according to a survey of frequency and quality of the food consumed. Samples of mature milk were obtained by hand expression 3 minutes into a nursing and immediately frozen at –70° C. Protein content was determined by spectrophotometry and total lipids by gravimetry. The fatty acid composition of lipids was determined by gas-liquid chromatography. Results and conclusions: Milk protein was no affected by maternal nutritional status; the total lipid content of milk samples from obese mothers was significantly increased relative to normal or overweight mothers. Of the total n-6 fatty acids, the milk from obese mothers had significant increases in the 18:2 n-6, and of total PUFA relative to the controls. There were no differences in the proportion of fatty acids of the n-3 series. Independently of nutritional status, the ratio n-6/n-3 fatty acids was very high compared with samples from developed countries. This is leading us to devise a strategy for a new dietary approach for nursing mothers.

Fatty acid composition of human milk in Western Iran

To investigate the fatty acid composition of mature human milk in Western Iran with special focus on trans fatty acids. Observational study. Milk samples were collected from 52 lactating mothers aging 19-39 y, from Western Iran. Subjects were asked to complete a diet questionnaire. Milk fatty acids were measured as 2-nitrophenylhydrazide derivatives by high-performance liquid chromatography. Saturated fatty acids were the main fraction of human milk (41.3%). Medium-chain fatty acids (C8:0-C14:0) constituted 24%, oleic acid (C18:1omega9) accounted for 30.9% and elaidic acid (C18:1T), the trans isomer of oleic acid, comprised 11.3% of the total milk fatty acids. Linoleic (C18:2omega6) and linolenic (C18:3omega3) acid contents were 13.8 and 1.1%, respectively. The level of the polyunsaturated fatty acids was 1.4% for arachidonic (C20:4omega6) and 0.2% for eicosapentaenoic (C20:5omega3) acid. The milk from Iranian lactating mothers, as compared to that from the American or European mothers, contained high levels of medium-chain and trans fatty acids. This difference may be attributed to the maternal diet with low animal protein and animal fat but with high carbohydrate and partially hydrogenated vegetable oils that carry large amounts of trans fatty acids. As the detrimental effects of trans fatty acids on blood lipids and cardiovascular diseases have been emphasized in the literature, a reduction of trans fatty acid content in the diet of Iranian mothers is suggested. Kermanshah University of Medical Sciences.

Changes of Fatty Acid Composition of Human Milk during the First Month of Lactation: A Day-to-Day Approach in the First Week

Background: Fatty acid composition of human milk (HM) is known to change considerably during lactation. However, we were unable to find data on changes of fatty acid composition of HM during the very early phase of lactation, i.e. in the first week of life. Subjects and Methods: HM samples were obtained from 18 healthy lactating women every day during the first week and thereafter on the 14th and 28th days of lactation. Fatty acid composition of colostrum and mature HM samples was determined by high-resolution capillary gas-liquid chromatography. Results: Values of the n-6 essential fatty acid, linoleic acid, in HM did not change significantly during the first month of lactation, whereas values of the n-3 essential fatty acid, α-linolenic acid, showed significant increases during the first 2 weeks of lactation (1st day: 0.49 [0.12], % weight/weight, median [ranges from the 1st to the 3rd quartile], 14th day: 0.69 [0.31], p < 0.05). In contrast, values of the n-6 long-chain metabolites, eicosadienoic-, dihomo-γ-linolenic- and arachidonic acid, as well as the values of the n-3 long-chain metabolites, eicosatrienoic-, and eicosapentaenoic acid exhibited significant decreases during the entire period investigated. The principal n-3 long-chain metabolite, docosahexaenoic acid, showed a significant increase between the 3rd and 14th days, but a significant decrease between the 14th and 28th days (3rd day: 0.15 [0.13], 14th day: 0.28 [0.11], p < 0.05, 28th day: 0.19 [0.12], p < 0.01). There were statistically significant positive correlations between arachidonic and docosahexaenoic acid values on the 1st (r = 0.67, p < 0.01), 5th (r = 0.56, p < 0.05) and the 6th (r = 0.53, p < 0.05) days of lactation. Conclusion: Fatty acid composition of HM changes significantly even during the first week of lactation. The lack of positive correlation between essential fatty acids and their long-chain metabolites suggests that it is not only the availability of essential fatty acids that influences the fatty acid composition of human colostrum.

Nutritional relevance of trans isomeric fatty acids in human milk

Trans isomeric fatty acids amount to about 2% of the fatty acid composition of human milk in Europe, whereas lower values were seen in Africa, and higher values were reported for North‐America. At least five human studies indicate that trans fatty acids may interfere with the metabolism of long‐chain polyunsaturated fatty acids. Conclusion: Trans isomeric fatty acids in human milk should be regarded as a potential confounding variable in studies investigating the role of long‐chain polyunsaturated fatty acids in the development of breastfed infants.

Polyunsaturated fatty acid supply with human milk.

Polyunsaturated fatty acids in human milk may derive from diet, liberation from maternal body stores, or endogenous synthesis from precursor fatty acids. The contribution of each of these sources has not been studied in detail. Although maternal diet is a key factor affecting human milk composition, other factors such as gestational age, stage of lactation, nutritional status, and genetic background are known to influence the fat content and fatty acid composition in human milk. Both linoleic and alpha-linolenic acids, the essential fatty acids, are present in human milk, as are several other n-6 and n-3 longer chain polyunsaturated fatty acids that are required for optimal growth and development of infants. The fatty acid profile of human milk from lactating women of different countries is remarkably stable, but there is variability in some of the components, such as docosahexaenoic acid, which is mainly due to differences in dietary habits. Tracer techniques with stable isotopes have been valuable in assessing the kinetics of fatty acid metabolism during lactation and in determining the origin of fatty acids in human milk. Based on these studies, the major part of polyunsaturated fatty acids in human milk seems not to be provided directly from the diet but from maternal tissue stores.

Polyunsaturated n-3 fatty acids and the development of atopic disease.

The relationship between polyunsaturated longchain fatty acids and atopy has been discussed for decades. Higher levels of the essential fatty acids linoleic acid and alpha-linolenic acid and lower levels of their longer metabolites in plasma phospholipids of atopic as compared to nonatopic individuals have been reported by several, but not all, studies. Largely similar findings have been reported in studies of cell membranes from immunological cells from atopics and non-atopics despite differences in methodology, study groups, and definitions of atopy. An imbalance in the metabolism of the n-6 fatty acids, particularly arachidonic acid and dihomo-gamma-linolenic acid, leading to an inappropriate synthesis of prostaglandin (PG) E2 and PGE1 was hypothesized early on but has not been corroborated. The fatty acid composition of human milk is dependent on the time of lactation not only during a breast meal but also the time of the day and the period of lactation. This explains the discrepancies in reported findings regarding the relationship between milk fatty acids and atopic disease in the mother. Prospective studies show disturbances in both the n-6 and n-3 fatty acid composition between milk from atopic and nonatopic mothers. Only the composition of long-chain polyunsaturated n-3 fatty acids was related to atopic development in the children, however. A relationship between lower levels of n-3 fatty acids, particularly eicosapentaenoic acid (20:5 n-3), and early development of atopic disease is hypothesized.

Fat content and fatty acid composition of fresh, pasteurized, or sterilized human milk.

In hospitals, human milk is subjected to heat treatment to reduce risk of transmission of infectious agents such as human immunodeficiency virus (HIV), hepatitis B, cytomegalovirus, and bacterial contamination, especially during feeding of banked milk to preterm infants. Fat losses due to heat treatment have been extensively studied in cow milk but have received little attention in human milk. We studied the effect of human milk pasteurization and sterilization on total fat content available to the infant as well as on fatty acid composition. Milk samples from 12 mothers (days 5-35 of lactation) were divided into three equal parts: one remained fresh, one was pasteurized (62.5 degrees C for 30min), and one was sterilized (120 degrees C for 30min). Fat content was determined gravimetrically, and the contribution of 30 fatty acids was determined by gas chromatography. For investigation of loss of available fat in sterilized milk, milk was collected from two additional mothers and analyzed with a modified extraction method. Total fat content was the same in fresh, pasteurized, and sterilized milk. The available fat content was 3.1+/-0.4g/dL (mean +/- SE) in fresh human milk, 3.1+/-0.4g/dL in pasteurized human milk, and 2.7+/-0.3g/dL (P < 0.001 vs. fresh) in sterilized human milk because of formation of a surface skin and fat adherence to the vial wall after sterilization. The fatty acid composition of 10 saturated, 10 monounsaturated, and 10 polyunsaturated fatty acids of both the n6 and n3 series was not affected by pasteurization. In sterilized milk there was a slight decrease of linoleic acid (C18:2n6; -0.7% vs. fresh; P = 0.006) and arachidonic acid (C20:4n6; -2.5%; P = 0.045). Pasteurization and sterilization do not affect total fat content of human milk, but sterilization may reduce available fat content by >10%. Fatty acid composition of human milk is not changed by pasteurization, but is slightly changed by sterilization.

Overview: conditionally essential nutrients: long-chain polyunsaturated fatty acids.

Several recent studies document a long-term beneficial effect of breast-feeding on later neurodevelopmental outcomes. The mechanisms involved are still unclear, but evidence is accruing that the fatty acid composition of human milk might play a role. In infants the composition of body fatty acids, from circulating erythrocyte lipids to brain phospholipids, is linked to the early diet (Farquharson et al. 1992; Makrides et al. 1994), and which fatty acids predominate among circulating lipids affects visual and neurodevelopmental performance test scores (Agostoni et al. 1995a, Makrides et al. 1995). These studies revealed that formula-fed infants showed low accretion of tissue long-chain polyunsaturated fatty acids (LC-PUFA) and lower visual and neurodevelopmental test scores than breast-fed infants.KeywordsHuman MilkEssential Fatty AcidDocosahexaenoic AcidErythrocyte Fatty AcidBody Fatty AcidThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Fatty Acid Composition of Human Milk in Different Regions of Slovenia

Background: The fatty acid composition of human colostrum lipids is influenced by maternal diet. We measured the fatty acid composition of colostrum lipids in Slovenia. Methods: Milk samples were collected on the 3rd day postpartum from 41 women recruited in three Slovenian regions (Celje, Ljubljana and Koper). Dietary habits were examined by a food-frequency questionnaire. In situ transesterification and capillary gas chromatography were performed to determine the fatty acid composition. Results: The coefficients of variation of the determinations of individual fatty acids accounting for >0.09 wt% were 1.87–5.91%. Between regional areas there were differences in the contents of linoleic (12.62–17.35 wt%; p < 0.001) and α-linolenic acid (0.70–1.07 wt%; p < 0.01), whereas the linoleic/α-linolenic acid ratios were similar (15.8 in Celje, 16.3 in Ljubljana and 17.9 in Koper). The highest proportion of docosahexaenoic acid (C22:6n–3) was in Celje (0.49 wt%), the lowest in Ljubljana (0.35 wt%; p < 0.05). The long-chain polyunsaturated fatty acid (LCP) content did not correlate with linoleic and α-linolenic acid, but there was a correlation between the sum of n–3 and n–6 LCPs. The colostrum linoleic/α-linolenic acid ratio was positively correlated with the body mass index during pregnancy. Conclusions: The fatty acid composition of colostrum lipids in Slovenia shows some variation according to geographical regions.

Fatty acid composition of human milk in Hungary

Fatty acid composition of human milk in Hungary

Docosahexaenoic acid transfer into human milk after dietary supplementation: a randomized clinical trial

Docosahexaenoic acid (DHA) is important for infant development. The DHA transfer from maternal diet into human milk has not been investigated in detail. We studied the effects of DHA supplementation on the fatty acid composition of human milk and the secretion of dietary (13)C-labeled fatty acids, including DHA, into human milk. Ten lactating women were randomized to consume, from 4 to 6 weeks postpartum, an oil rich in DHA (DHASCO, 200 mg of DHA/day) (n = 5) or a placebo oil (n = 5). Dietary intakes were followed by 7-day protocols. On study day 14 a single dose of [U-(13)C]DHASCO was given orally, milk samples were collected over 48 h, and milk production was recorded. Milk fatty acid composition was determined by gas-liquid chromatography and isotopic enrichment was determined by gas chromatography- combustion-isotope ratio mass spectrometry (GC-C-IRMS). Milk DHA content did not differ between the supplemented and placebo group at study entry (0.29 vs. 0.28 wt%, median). After 2 weeks of supplementation the milk DHA content was almost 2-fold higher in the supplemented versus placebo group (0.37 vs. 0.21 wt%, P = 0.003). Cumulative recovery of [(13)C]palmitic, [(13)C]oleic, and [(13)C]docosahexaenoic acids in human milk at 48 h was similar between supplemented and placebo groups (palmitic acid 7.40 vs. 8. 14%, oleic acid 9.14 vs. 9.97%, and docosahexaenoic acid 9.09 vs. 8. 03% of dose, respectively). Notable lower recovery was observed for [(13)C]myristic acid in both the supplemented and placebo groups, 0. 62 versus 0.77% of dose. Dietary DHA supplementation increases the DHA content in human milk. DHA transfer from the diet into human milk is comparable to palmitic and oleic acid transfer.

Polyunsaturated fatty acid concentrations in human hindmilk are stable throughout 12-months of lactation and provide a sustained intake to the infant during exclusive breastfeeding: an Italian study

While a wealth of data on the fatty acid composition of mature human milk has been published, limited information is available on the quantities of individual fatty acids supplied to the suckling infant with maternal milk, through the whole first year of life. Our aim was to qualitatively and quantitatively evaluate the fatty acid composition of human milk from Italian mothers, throughout extended lactation with particular emphasis on the long-chain polyunsaturated fatty acids. We have thus measured the total fat content and the concentrations of major fatty acids by quantitative GLC in pooled breast hindmilk collected from all feedings over 24 h at colostrum, 1, 3, 6, 9 and 12 months in ten mothers recruited after delivery of full-term infants. Total saturated fatty acids progressively increase and total monounsaturated progressively decrease as percentage levels, while among long-chain polyunsaturated fatty acids, percentages of arachidonic acid and docosahexaenoic acid decrease from colostrum up to the third month. Hindmilk total lipids (mg/dl) rise more than twofold up to 3 months, and then remain stable. The amounts (mg/dl) of linoleic acid and alpha-linolenic acid progressively increase, following the trend of total fat, while arachidonic and docosahexaenoic concentrations (mg/dl) remain stable throughout the whole nursing period. Assessment of the intakes per kg body weight shows different trends for the individual major long-chain polyunsaturated fatty acids supplied to the infant from hindmilk during exclusive breast-feeding (3 months). This information may be useful for the evaluation of infant intakes during extended lactation.

The fatty acid composition of human milk in northern Nigeria.

The authors previously reported that the milk of Yoruba women in southwestern Nigeria was deficient in alpha-linolenic acid and contained a high percentage (42%) of medium chain-length fatty acids (MCFA, C10-C14). In the present study, the authors used capillary gas-liquid chromatography to analyze the milk of Hausa women in the northern region of Nigeria. The milk of the Hausa women contained 27% MCFA, 10.6% linoleic acid, 0.41% alpha-linolenic acid, 0.52% arachidonic acid, and 0.32% docosahexaenoic acid. The proportion of alpha-linolenic acid in the serum phospholipids of a subset of exclusively breastfed infants (n = 15; mean age, 6.2 +/- 0.3 months) was below the limit of detection (< 0.03%). While the milk of women in northern Nigeria is adequate with regard to n-3 and n-6 fatty acids, to satisfy the requirements for alpha-linolenic acid, it may be necessary to supplement the infants of these women after the first 6 months of life.

Fatty acid composition of human milk in Kuwaiti mothers

Kuwaiti diet is exceptionally rich in fat, carbohydrates and proteins. In addition, subjects in Kuwait are exposed to extreme heat and sun light. Fatty acid profiles of human milk obtained from 19 full breast feeding Kuwaiti mothers were analyzed. Dietary patterns for individual mothers were determined by 24 h dietary recall and food frequency questionnaire. The fatty acid content of human milk was affected by the diet consumed by the lactating mother. The content of long chain polyunsaturated fatty acids (LCP) in human milk lipids did not correlate with their parent fatty acids like linoleic and α-linolenic acids. However the human milk LCP were related to the of content of LCP in the maternal diet. Mothers reporting a high fish consumption showed significant amounts of C22:6, ω3 and C20:5, ω3 fatty acids. As a general conclusion, breast milk produced by a well nourished mother is better suited to meet the lipid requirements of infants.

Aspects of whey protein usage in infant nutrition, a brief review

Summary Demineralized whey, whey protein concentrates and, to a lesser extent, some other whey protein fractions are key raw materials in infant formula manufacture. An estimate of the amount of whey protein used in infant formulae annually is in the order of 30–40 000 tons. Infant formula development has been a long lasting effort to approach the nutrient composition of human breast milk while using cow's milk as the raw material. This required extensive fractionation of the bovine milk followed by subsequent recombination of specific fractions. Criteria to judge protein quality and define adequate protein quantity in infant formulae have also evolved. Early criteria for protein adequacy were based on Protein Efficiency Ratio (PER) testing in rats and/or nitrogen balance studies. More recently, the approach of essential amino acid scores, based on the amino acid pattern of mature human milk has been put forward. Regulatory authorities such as CODEX, EC Commission and more recently LSRO in its suggestions to FDA in the USA, have issued reference amino acid profiles which are based on the average amino acid composition of human milk. The same authorities have also regulated protein density in infant formulae, accounting for an observed protein mean density of 1.5–1.6 g /100 kcal in mature breast milk. The minimum protein level of cow's milk based infant formulae was fixed at 1.8 g/100 kcal by these authorities. Current infant formulae have however protein densities significantly higher than the minimum of 1.8 g/100 kcal. The higher protein density compensates for the likeliness that the protein in the best of the formulae, is not as ideal for the infant as the protein from breast milk. Even if a complete equivalence may be difficult to reach, efforts continue in the direction of further optimizing the protein quality in terms of essential and semi‐essential amino acid profiles. This is the only way to be able to lower the protein content in a formula to levels that are nearer to the low protein density of human milk. Among several possibilities, the increase in the mass proportion of bovine α‐lactalbumin is a particularly promising way to achieve this goal.

A comparative study of fatty acids in human breast milk and breast milk substitutes in Kuwait

Specific standards of infant formula lack detailed recommendations about fatty acids in formula preparations except for linoleic acid [18:2(n-6)]. Many fatty acids were known to be very important in the development of early life. Human breast milk is considered the best model for designing breast milk substitutes with the ideal nutritive value. Fatty acid composition of human milk obtained from 19 full breast feeding Kuwaiti mothers and in 22 adapted formulas (breast milk substitutes) was determined by using capillary gas chromatographic technique. Palmitic acid (16:0), and as a consequence, total saturated fatty acids were found to be lower in human milk than formula milk. However, total mono- and polyunsaturated fatty acids were found to be higher in human milk than in formula milk. Linoleic acid [18:2(n-6)] content in formula milk was similar to human milk, while α-linolenic acid [18:3,(n-3)] showed a higher percentage in formula milk. Evidently formula milk preparations provide essential fatty acids for infants in adequate amounts as a results of their fat blend. Formula milk tends to contain lower percentages of cis- and trans-isomeric fatty acids compared to human milk. In contrast to human milk, most formulas lacked physiologically important long-chain polyunsaturated fatty acids (LCP).

The amino acid composition of human milk corrected for amino acid digestibility.

Human milk was collected from women in their 10th-14th weeks of lactation, and was analysed for amino acids. Corrections were made for losses of amino acids which were presumed to occur during acid hydrolysis, using a non-linear mathematical model that describes the simultaneous processes of amino acid yield and decay. The mean amino acid composition of the human milk was found to be similar to previously reported estimates, although the cysteine content of the human milk in the present study was 20% higher than the average literature estimate. True (corrected for endogenous amino acid excretions) ileal amino acid digestibility of human milk was determined using the 3-week-old piglet as a model animal for the human infant. The piglets were given either human milk (n 6) or a protein-free diet (n 6) for a 6 d experimental period. Cr2O3 was added as an indigestible marker, to both the human milk and protein-free diet. At the end of the experimental period the piglets were anaesthetized and samples of digesta removed from the terminal ileum of each piglet. After sampling the piglets were killed. Endogenous ileal excretions of amino acids were determined in piglets fed on the protein-free diet. The true digestibilities of total N and amino acid N were 88% and 95% respectively. The true ileal digestibility of the non-amino acid N fraction in human milk, when calculated by difference was only 50%. The true digestibility of the amino acids in human milk ranged from 81-101% with threonine (86%) being the least digestible essential amino acid. When the true ileal digestibility values were used to correct the amino acid composition of human milk, the pattern of digestible amino acids in human milk was different compared with the currently recommended pattern of amino acid requirements for the infant.

Approaches and Considerations in Determining the Protein and Amino Acid Composition of Term and Preterm Infant Formula

Abstract Infant formula provides the sole source of protein and amino acids for many infants during the first year of life and thus it is mandatory that formula manufacturers make every effort to produce a formula with the optimal level of protein and mix of amino acids. This paper reviews our approach in determining the protein and amino acid composition of a new infant formula. The perils of simply mimicking the whey to casein ratio or the amino acid composition of human milk are discussed as is the advantage of developing a formula in which the protein and amino acid mixture produces a plasma amino acid profile in the formula-fed term infant that most closely resembles the plasma profile of the breast-fed infant. In contrast, the goal of formulating the protein and amino acid composition of an enteral feeding for the preterm infant is to replicate the intrauterine rate of protein accretion without causing metabolic stress. We discuss theoretical approaches for determining the protein requirements of preterm infants. In addition we review the clinical trials that more precisely help to define the optimal protein intake for premature infants.

Importance of milk and diet on the ontogeny and adaptation of the intestine.

Importance of milk and diet on the ontogeny and adaptation of the intestine.