Fatty acid composition of human milk from South African black mothers consuming a traditional maize diet

Fatty acid composition of mature human milk of rural and urban black South African mothers was determined by gas-liquid chromatography. Rural mothers consumed traditional diets low in animal protein and fat, and high in carbohydrate and fibre. Urban mothers consumed more varied, partially westernized diets, and two-thirds were overweight. Plasma cholesterol concentrations were significantly lower in the rural group (3.64 vs 4.75 mmol/l, P less than 0.01). Milk of rural mothers contained significantly higher percentages of C10:0, C12:0, and total saturated fatty acids. Fatty acids C8:0-C14:0 synthesized de novo in the mammary gland were substantially higher in the milk of the rural mothers (24.7 vs 15.9 per cent). Conversely, the milk of the urban group contained higher percentages of monounsaturated fatty acids, 18:3 omega 3 and 20:2 omega 6. The ratio of polyunsaturated to saturated fatty acids in rural samples was 0.36 +/- 0.13 compared to 0.41 +/- 0.15 in urban samples (P greater than 0.1). It is concluded that maternal dietary intake significantly affects milk composition, as demonstrated by the high percentages of fatty acids synthesized de novo in the mammary gland of rural mothers habituated to low-fat, high-carbohydrate intakes.     

Fatty acid composition of human milk in atopic Danish mothers

BACKGROUND: Atopic dermatitis has been related to a disturbed metabolism of polyunsaturated fatty acids (PUFAs). OBJECTIVE: We tested whether the PUFA composition of breast milk differs significantly between mothers with atopic dermatitis, mothers with other types of atopy, and nonatopic mothers. We also investigated whether differences in diet can explain possible observed differences. DESIGN: Mothers with current or previous asthma (n = 396) were divided into 3 groups according to history of atopic dermatitis and allergic rhinitis. Breast-milk samples were collected from 314 women approximately 3 wk after delivery. The habitual diet of the women was assessed with food-frequency questionnaires in the 25th week of gestation (n = 207). Breast-milk samples and simultaneous dietary data from 14 nonatopic mothers were used for comparison. RESULTS: Compared with the milk of nonatopic mothers, that of atopic mothers had significantly higher concentrations of 22:5n-6 and lower concentrations of 20:5n-3; moreover, 20:4n-6/20:5n-3, 22:5n-6/22:6n-3, and long-chain n-3 PUFA/18:3n-3 were shifted toward n-6 PUFA and 18:3n-3 in nonatopic and atopic mothers, respectively. No differences in breast-milk PUFA composition were evident between the subject groups. The diets of the groups differed only slightly with respect to protein intake. However, the PUFA composition of the breast milk was associated with diet and time of milk sampling, and the above difference in milk PUFAs disappeared when those factors were taken into account. CONCLUSION: Our data do not support the possibility that the fatty acid composition of breast milk is affected by atopic dermatitis or atopy in general, because most differences in breast-milk PUFA composition appear to be explained by the diet.     

Lipid composition in human breast milk from Granada (Spain): changes during lactation

OBJECTIVE: To determine possible differences of composition in the course of lactation, phospholipid (PL) classes (phosphatidylethanolamine, phosphatidylinositol, phosphatidylserine, phosphatidylcholine, and sphingomyelin) and fatty acid composition of PL and triacylglycerol (TGs) fractions of milk fat were analyzed in 66 samples from mothers from Granada (Spain) who gave birth to full-term infants. Analyses included colostrum, transitional milk, and mature milk. METHODS: After milk fat extraction, PLs and TGs were separated by thin-layer chromatography and fatty acids of each fraction were converted into their methyl esters, which were analyzed by gas chromatography. PL classes were determined by high-performance liquid chromatography using an evaporative light-scattering detector. RESULTS: Mature human milk showed a lower content (P = 0.020) of PLs than did the other milks. Percentage of sphingomyelin was constant for all stages of lactation, whereas the percentage of phosphatidylcholine in mature milk was significantly lower (P < 0.05) than in colostrum and transitional milk. TGs in mature human milk contained lower percentages (P < 0.001) of arachidonic acid, docosahexaenoic acid, and nervonic acid. Docosahexaenoic acid and nervonic acid also showed a significant decrease (P < 0.001) in total PLs from colostrum and mature milk. CONCLUSIONS: The composition of PL classes and fatty acids in PLs and TGs in milk of mothers in Granada (Southern Europe) is different from that in milk from mothers in other parts of the world. In addition, the ratio of long-chain polyunsaturated fatty acids delivered in the form of PLs to long-chain polyunsaturated fatty acids delivered in the form of triacylglycerols diminishes as lactation proceeds.     

Bacteriostasis of Escherichia coli by milk. V. The bacteriostatic properties of milk of West African mothers in the Gambia: in-vitro studies.

Bacteriostatic activity was measured in 244 specimens of milk collected during 1977 throughout lactation of up to one year from 78 mothers; the activity varied from very good to fair and only seven were inactive. There was a wider range of activity than was found previously in milk from English mothers. Activity usually fell slowly during lactation but some of the Gambian mothers produced milk of very high activity, like that of colostrum into the second week of lactation, and two mothers did so at six and nine months; other mothers produced good-activity milk throughout lactation. The bacteriostatic activity varied little with the season but slight decreases from that expected were found after the high incidence of infant diarrhoea towards the end of the rainy season. The bacteriostatic activity of most of the milk tested could be prevented by iron salts but that of colostrum and some of the milks with high activity could not. Only these highly active colostra and milks were inhibitory in vitro when the inoculum was increased from 10(4) to 10(6) organisms per ml. These and less active milks were able to inhibit the smaller, standard inoculum for longer than 3 h with the addition of bicarbonate and extra iron-binding protein at the concentrations likely to be present in vivo. Both commensal and pathogenic E. coli were inhibited to a similar degree by these milks and there was no evidence of serotype specificity.     

Ascorbic acid supplementation and regular consumption of fresh orange juice increase the ascorbic acid content of human milk: studies in European and African lactating women

BACKGROUND: Little is known about the influence of an increased intake of ascorbic acid (AA) on human milk AA output. OBJECTIVE: We aimed to compare human milk AA content in European and African women and to evaluate the influence of increased AA intake on human milk AA output. DESIGN: Apparently healthy lactating women were recruited. AA was analyzed by titration with 2,6-dichlorophenol-indophenol. RESULTS: Mean human milk AA was approximately 50% lower (P < 0.001) in the African women (31 mg/kg; n = 171) than in the European women (63 mg/kg; n = 142). AA supplementation (1000 mg/d for 10 d) increased mean human milk AA from 19 to 60 mg/kg (P < 0.001) and from 60 to 70 mg/kg (P = 0.03) in 18 African and 10 European women, respectively. In 11 African women, mean human milk AA increased from 17 to 36 mg/kg (P < 0.001) after intake of 100 mg AA/d for 10 d. In African women, intake of 1 serving of orange juice per week had no significant effect, whereas 3 or 5 servings/wk ( approximately 100 mg AA/serving) for 6 wk increased mean human milk AA from 16 to 32 mg/kg (n = 13) and from 21 to 46 mg/kg (n = 13), respectively (P < 0.001). CONCLUSIONS: Human milk AA can be doubled or tripled by increased intake of AA in women with low human milk AA content at baseline. The response to a relatively high dose of AA was modest in European women in contrast with the 3-fold increase in mean human milk AA content in African women. These data indicate that human milk AA content is regulated.     

Flavin composition of human milk

The identity and quantity of greater than 95% of the flavins present in human milk were assessed by acid-phenol extractions followed by high-performance liquid chromatography. Flavin adenine dinucleotide (FAD) and riboflavin were the predominant flavins, followed by 10-(2'-hydroxyethyl)-flavin. In addition, traces of 7 alpha- and 8 alpha-hydroxyriboflavins (7-hydroxymethylriboflavin and 8-hydroxymethylriboflavin, respectively) were detected. The flavin content of human milk samples in this study was higher than contents reported in earlier studies where no correction for the internal fluorescence quenching of FAD was made. This finding may have implications for dietary recommendations concerning both lactating women and infants. In practical terms, the types and amounts of flavins in human milk are very similar to those recently reported for cow milk.     

Lipid and retinol contents in the milk of Egyptian mothers with normal and sick infants

Mature breast milk was collected from Egyptian lactating mothers (N = 35) and was analyzed for its lipid, retinol and carotene contents. Mean values of 3.78 +/- 0.3%, 29.5 +/- 4.92 micrograms/100 g and 65.2 +/- 16.28 micrograms/100 g were obtained for lipid, retinol and carotene in the milk of mothers with normal infants. The milk of mothers with sick infants was inferior in its quality with respect to the lipid and retinol contents. Milk retinol level correlated significantly with the growth of the normal infants.     

北京市顺义区341例乳母基本状况及乳汁成分分析

目的了解北京市顺义区341例乳母基本情况及乳汁成分,为今后进行相应的营养干预提供指导。方法以问卷的形式询问乳母健康状况调查表,标准方法测量乳母的身高、体重、腰围、臀围。乳汁采集是指采空乳母一侧乳房的乳汁,乳汁样品用于母乳成分分析。结果顺义区341例乳母生产后体重、腰围、臀围逐渐降低,孕期体重增加平均为18.3 kg;孕期出现的临床症状以小腿痉挛和牙龈出血为主,分别为65.69%和54.25%;乳母使用催奶方法的有63.53%;初乳乳汁分泌量较少,单侧乳汁平均重量52.7g,2~3月乳汁分泌量最高,平均重量135.4 g;不同阶段乳汁成分中蛋白质和碳水化合物差别有统计学意义(P<0.05)。结论调查结果表明顺义区341例乳母孕期体重增加远大于建议值,孕期小腿抽筋和牙龈出血发生率高,乳母使用催奶方法主要是食疗,用于预防奶量不足;乳母乳汁成分不同阶段蛋白质和碳水化合物含量不同,脂肪和能量含量没有变化。     

Fatty acid composition of human milk in mothers of preterm and full-term infants in the first three weeks of lactation

INTRODUCTION: It is a classical question of infant nutrition whether fatty acid composition of human milk differs in mothers of preterm as compared to those of full-term infants. AIMS AND METHODS: The authors analysed fatty acid composition of milk samples obtained five times during the first month of lactation from mothers of preterm (n = 8, gestational age: 28.0 [4.2] weeks, birthweight: 1235 [420] g, median [IQR]) and full-term (n = 10, gestational age: 38.5 [2.7] weeks, birthweight: 3375 [282] g) infants with high-resolution capillary gas-liquid chromatography. RESULTS: Maternal age, body mass index and eating habits of the mothers did not differ between the two groups. Neither did fat contents of human milk differ between the two groups. Values of linoleic (C18:2omega-6) and alpha-linolenic (C18:3omega-3) acid did not differ. Values of arachidonic acid (C20:4omega-6) and docosahexaenoic acid (C22:6omega-3) were significantly higher following preterm as compared to full-term delivery. Values of the intermediary metabolites g-linolenic acid (C18:3omega-6), dihomo-gamma-linolenic acid (C20:3omega-6), octadecanotetraenoic acid (C18:4omega-3) and eicosatrienoic acid (C20:3omega-3) were also significantly higher in human milk samples of mothers of preterm as compared to those of full-term infants. CONCLUSION: Significantly higher contribution of long-chain polyunsaturated fatty acids in breast milk of mothers giving birth to preterm as compared to full-term infants supports the concept, that preterm infants would benefit more from feeding their own mothers milk than from receiving donor milk.     

Effects of maternal dietary intake on human milk composition

The composition of human milk can be affected by the diet consumed by the lactating woman. The influence of the maternal diet on milk composition varies in magnitude between nutrients; for some nutrients no effect at all has yet been documented. Concentrations of fatty acids, fat-soluble and water-soluble vitamins in milk are, in general, significantly affected by the levels of these nutrients in the diet. Protein concentration may be affected under some conditions, although the magnitude of this change appears relatively limited. Lactose, mineral, trace element and electrolyte concentrations seem comparatively resistant to varying maternal intakes. Although there has been significant progress in this research area in the past decade, many early studies are difficult to interpret due to limitations in the study design and analytical methods. This review demonstrates a distinct need for carefully controlled studies on the effects of both nutrient deficiencies and supplements on milk composition. Interactions among nutrients, homeostatic mechanisms and energy balance (weight loss) are factors that need to be studied further. Information from such research will suggest strategies for nutrition intervention in areas of poor nutrition and provide dietary guidelines for lactating women.     

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

BACKGROUND/OBJECTIVESBreast 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/METHODSMilk 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.RESULTSThe 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.CONCLUSIONSThese results warrant future studies to explore factors that may be associated with changes in macronutrient content in human milk.     

Birth weights of black African babies of migrant and nonmigrant mothers compared with those of babies of European mothers in Portugal

PURPOSE: The study aim is to investigate differences in birth weights between babies of foreign-born black African, Portugal-born black African, and Portugal-born white mothers. METHODS: Hospital records for Amadora and Sintra from July 2001 to June 2002 were collated and 2949 Portugal-born white, 461 Portugal-born black African, and 817 foreign-born black African live singleton babies were identified. The impact of biologic and social factors (infant sex, maternal age, parity, gestational age, and maternal smoking, education, and occupational class) and mode of delivery on birth weights was assessed by using multivariable regression models. RESULTS: African mothers were more likely to be of lower socioeconomic status than white Portuguese mothers, among whom rates of smoking were two to three times greater (21% among white Portuguese mothers). Small preterm babies comprised 1.5% of white Portuguese babies, 2.3% of babies of Portugal-born African mothers, and 3.9% of babies of foreign-born African mothers (p < 0.05 compared with white Portuguese babies). Compared with white Portuguese babies, mean birth weight of term babies, adjusted for sex, among Portugal-born African mothers was -24.6 g (95% confidence interval, -70.1-20.9), and among foreign-born African mothers, was +38.8 g (95% confidence interval, 2.9-74.8). Adjustment for parity, maternal age, and gestational age decreased the significant birth weight advantage of babies of foreign-born African mothers to +2.3 g (95% confidence interval, -31.9-36.5). Among nonsmokers, after adjusting for these factors, white Portuguese babies were heavier (40 g; p < 0.05) than babies of foreign-born African mothers, but among smokers, they were lighter (163 g; p < 0.05). CONCLUSIONS: Compared with white Portuguese babies, mean birth weight of term babies of foreign-born African mothers was greater, and that of babies of Portugal-born African mothers was intermediate. These differences were related to a combination of biologic factors and smoking.     

Length of gestation and nutritional composition of human milk

A comparative analysis of the composition of milk produced during the first 14 days of lactation by mothers who deliver prematurely and those who deliver at term is described and these values are contrasted with the composition of donor milk specimens. Twenty-four-hour milk collections (days 3, 7, and 14 postpartum) were obtained from nine mothers delivered between 37 to 42 wk gestation (term) and from 14 mothers who delivered between 28 to 36 wk gestation (preterm). A single spot milk collection was obtained from nine mothers who were 6 to 10 months postpartum (donor). Term and preterm milk was compared on specific postpartum days using an analysis of covariance controlling for 24-h milk volume. The protein, carbohydrate, fat, and energy content varied in a similar fashion in term and preterm milk over the 14 postpartum days studied. Furthermore, there was no significant difference between the two milk groups on any single postpartum day evaluated in terms of protein, carbohydrate, fat, or energy concentration. The milk volumes were significantly greater from the mothers delivered at term on days 7 and 14 (p less than 0.01) and the protein content of both term and preterm milk was negatively correlated with milk volume (r = -0.6 or more on each day studied). The nutrient and energy composition of spot donor milk was highly variable and frequently quite different from either term or preterm 24-h milk collections. These data indicate that milk from mothers who deliver prematurely does not contain significantly different concentrations of nutrients or energy than milk from mothers delivered at term and suggest that the differences previously noted between the two groups may be related to 24-h milk volume.     

母乳中脂联素水平及其影响因素的研究

【目的】调查母初乳和成熟乳中脂联素水平并探讨其与母婴之间的关系。【方法】应用ELISA测定母乳脂联素水平,分析母乳脂联素与母亲体质指数(body mass index,BMI)及母、脐血糖、胰岛素水平的关系。【结果】母乳中含有丰富的脂联素,初乳中脂联素水平(27.9μg/L,5.7-367.1μg/L)明显高于成熟乳(10.9μg/L,3.0-179.6μg/L)(P<0.01)。进一步,母初乳中脂联素水平与母亲妊娠晚期BMI呈临界相关(r=0.33,P=0.069),与母血脂联素水平呈显著正相关(r=0.53,P<0.01),母初乳脂联素水平亦与脐血糖(r=0.52,P<0.01)及脐血胰岛素水平正相关(r=0.53,P<0.01)。【结论】母乳中含有丰富的脂联素,且与母血及母亲BMI相关。母乳中持续存在的脂联素在母乳喂养儿代谢发育中可能有着潜在的意义。     

Nutrients and contaminants in human milk from mothers on macrobiotic and omnivorous diets.

The effect of alternative dietary habits and prolonged lactation on the nutrient and contaminant concentrations in human milk was studied. The study sample consisted of mothers on macrobiotic diets, containing little or no diary products and meat, at 2-3 months postpartum (n = 9) and 9-13 months postpartum (n = 12), and mothers on omnivorous diets at 2-3 months postpartum (n = 10). Protein and zinc concentrations in breast-milk from macrobiotic mothers decreased with stage of lactation. After adjustment for stage of lactation, milk from macrobiotic mothers contained less calcium, magnesium and saturated fatty acids C15:0-C20:0, and more polyunsaturated fatty acids. Observed tendencies for lower protein and fat and higher lactose concentrations in the macrobiotic group were not statistically significant. Concentrations of vitamin B12, HCB and polychlorinated biphenyls (PCB 118, PCB 138, PCB 153 and PCB 180) were lower in the macrobiotic group. After adjustment for confounding variables, meat and fish consumption, but not dairy products, contributed to vitamin B12 concentrations. Meat and diary products strongly contributed to breast-milk concentrations of dieldrin and PCBs, fish to PCB 118, and smoking to DDT and dieldrin. Our findings suggest that breast-milk contamination could be reduced by abstinence from smoking and a moderate intake of animal products. However, risk of nutritional deficiencies rules out complete avoidance of meat, fish or diary products. Quantitative research on the effects of a reduced consumption of animal products, as well as smoking, on breast-milk contamination is warranted.     

Influence of sampling on fatty acid composition of human milk

To study effects of sampling on the fat and fatty acid composition of human milk, three subjects each obtained four complete expressions of milk in sequential fractions from each breast. Two subjects collected partial expressions of about 5 ml of milk from each breast frequently over a 2-mont period. Milk samples were analyzed gravimetrically for fat and by gas chromatography for the fatty acids 10:0, 12:0, 14:0, 14:1, 16:0, 16:1, 18:0, 18:1, and 18:2. While hindmilk contained a higher percentage of fat than foremilk, fatty acid composition of the milk fat did not vary throughout a nursing. Fatty acid composition from pairs of left and right breast samples collected at the same nursing did not differ. Therefore, fatty acid analyses of human milk will be representative of the entire nursing if the sample is taken from either breast at any time during the nursing.