Dietary supplements for the lactating mother: influence on the trace element content of milk

Milk production is a complex process where nutritional factors interact with structural hormonal and behavioural influences. In recent years important advances have been made in understanding the role of the nutritional status of lactating women on the outcome of breastfeeding. Many questions remain unanswered about the exact requirement of trace elements for lactating mothers. The effect of dietary zinc, copper and iodine supplements on the milk concentration of these micronutrients was studied. The supplementation trial employed a specific balanced nutritional supplement prepared for the nursing mothers. The study was carried out on women living in Ferrara and its surrounding area. The population under study was healthy Italian mothers, of good socioeconomic status, and their normal infants. In total, 32 women were enrolled in the study and 22 completed it. The infants (9F, 13M) were full-term, healthy singletons and were put to breast within 12 h of birth. All women who finished the study completed a 3 d dietary record. Nutrient analysis revealed the following mean daily dietary trace element intake in the lactating mothers: zinc = 12 mg, copper = 1.4 mg and iodine = 145 microg. The zinc and copper dietary intake was in agreement with the daily intake proposed for nursing Italian mothers, while the daily intake of iodine was below the recommended intake of 200 microg. The breastfeeding mothers were placed in 2 groups, with 7 primiparas and 4 multiparas per group: lactating women eating a traditional Italian diet without vitamin and mineral supplements, and lactating women enrolled in the nutrification programme and given a nutritional supplement to their traditional diet. The supplement (PerMamma Abbott) provided 20mg zinc sulfate, 2mg copper sulfate and 116 microg potassium iodide. These quantities cover about 60-90% of the recommended intake for nursing Italian mothers. Samples of 10 ml of milk were collected at 3, 30, 90d postpartum. Zinc milk concentrations declined significantly over the study period for all lactating subjects, without differences in the rate of decline between the women who started supplementation during lactation and those who did not. Copper did not change during the first month of lactation, then declined at day 90 in supplemented and unsupplemented women, without significant differences between the two groups. An early sharp decline in milk iodine occurred in all lactating subjects, independently of iodine supplementation. After the first month of lactation breast milk iodide levels remained stable in all subjects under study. No significant differences between the two study groups were observed. The lack of correlation between the iodide level in breast milk and maternal dietary intake of iodine is not in agreement with previously published reports. The present results indicate that in healthy, well-nourished lactating Italian women, whose diet is adequate, the levels of zinc, copper and iodine in milk are not influenced by short-term supplementary intakes and that the milk levels of the trace elements studied are maintained over different levels of intake. Further research and examination by longitudinal studies are needed to establish the exact relationship between the amount of iodine furnished to the nursing mother and the iodine content of human milk. The role of compensatory homeostatic mechanisms which act during lactation needs further consideration and closer scrutiny.     

Vitamin K concentrations in the maternal milk of Japanese women

Aim: To determine the concentration of vitamin K including K1 (phylloquinone) and K2 (menaquinone-n; MK-n) in the maternal milk of Japanese women. Methods: We collected human milk samples from more than 4000 mothers living throughout Japan from December 1998 to September 1999, and analysed the contents of vitamin K1 and K2 in 834 of the samples. We defined as group A the 555 samples among them that met the following conditions: breast milk of mothers who were under 40 y old, not in the habit of smoking and/or using vitamin supplements, and whose babies showed no symptoms of atopy and whose birthweights were 2.5 kg or more. Vitamins extracted from the enzymatic hydrolysates of the human milk were purified with a Sep-Pak Plus silica cartridge, and then measured by a method based on high-performance liquid chromatography (HPLC) combined with coulometric reduction and fluorometric detection. Results: The mean concentration of vitamin K (K1 + K2) of mothers of group A and all groups were 0.434 ± 0.293 and 0.517 ± 1.521 μg/100 ml (average ± SD), respectively, and menaquinones containing 4, 6 and 7 isoprenoid residues could be detected in the milk samples. Vitamins K1 and MK-4 were found to be predominant in the milk samples, and the concentration of MK-4 in colostrum was higher than that of MK-4 in mature milk. We also found that the MK-7 concentration in the milk of mothers living in eastern Japan was higher than that of mothers living in western Japan.

Conclusion: The different features of vitamin K1 and MK-7 concentrations in the milk of Japanese women may be due to differences in dietary foods.     

Vitamin A and E content of human milk at early stages of lactation

The influence of gestational age and lactational stage on carotene, retinol ester, alpha-tocopherol and gamma-tocopherol content of early human milk was studied. These nutrients were analyzed simultaneously using normal phase high-performance liquid chromatography. Serial samples of colostrum and early milk representative of complete early morning expressions were obtained during the first 6 weeks post-partum from mothers giving birth prematurely (PT) and at term (FT). Colostrum carotene content declined significantly during the first week of lactation. There was no apparent gestational age effect on milk carotene levels. The longitudinal pattern of change observed for milk retinol ester and alpha-tocopherol content was however, significantly different between PT and FT milk. Retinol ester levels were similar on days 1-2 postpartum reaching a maximal level on days 3-4 postpartum in FT milk. For PT milk the maximum retinol ester concentration occurred on days 6-7 postpartum. Retinol ester content decreased throughout lactation. The rate of decline was more marked for FT milk. The concentration of alpha-tocopherol in colostrum was higher in FT milk. On all subsequent days examined the level of alpha-tocopherol was greater in PT milk. For both FT and PT milk the alpha-tocopherol concentration was higher during the first week of lactation when compared with following weeks. gamma-Tocopherol levels were not influenced by gestational age or lactational stage. Levels of milk vitamin A and E did not appear to correlate with maternal intake. Colostrum levels of vitamin A and E may imply active sequestration by the mammary gland in compensation for limited placental transport. Early milk content of vitamin A and E appears to parallel mammary gland lipid synthesis.     

Total lipid content and fatty acid composition of preterm human milk

The total lipid content and fatty acid composition of preterm human colostrum and milk were analyzed from aliquots of 24-h collections of colostrum, transitional milk, and mature milk obtained from 21 women who had delivered premature infants with a mean birth weight of 1,049 +/- 38 g (mean +/- SEM) and a mean gestational age of 29 +/- 0.4 weeks. The total lipid content increased significantly with time of lactation (p less than 0.001), from 1.99 +/- 0.25 g/dl in colostrum to 3.89 +/- 0.28 g/dl in mature milk. With respect to the fatty acid pattern, the percentages of 12:0 and 14:0 increased significantly (p less than 0.001), while those of 16:0 (p less than 0.05) and 18:1 (p less than 0.001) decreased significantly with time of lactation. The percentages of 10:0, 16:1, 18:0, 18:2, and 18:3 did not vary significantly with the duration of lactation. Similar compositional changes have been described in term human colostrum and milk as the duration of lactation progresses.     

Relationship of milk intake and vitamin K supplementation to vitamin K status in newborns

Vitamin K status was evaluated by measuring blood acarboxyprothrombin (PIVKA-II) levels on the fifth day of life. The incidence of PIVKA-II-positive infants was higher in breast-fed babies than in those given supplementary (mixed) feeding. The median of total amount of milk intake during the first 3 days was significantly lower in PIVKA-II-positive infants than in PIVKA-II-negative infants among infants given both types of feedings. In addition, there was a significant negative correlation between a positive PIVKA-II proportion and the amount of milk intake in the breast-fed babies. The minimum dose of vitamin K2 necessary to prevent a positive PIVKA-II reading was 15 micrograms among babies with a normal absorption potential.     

早产儿脐血维生素K依赖因子水平及产前补充维生素K1对其影响的研究

目的了解早产儿是否存在维生素(Vit)K依赖因子水平低下及其与早产儿脑室周围-脑室内出血的关系,探讨产前补充维生素(Vit)K1对早产儿血浆VitK依赖因子水平的影响及对脑室周围-脑室内出血的预防作用.方法将有早产可能且至分娩时孕周不足35周的孕妇分为两组对照组133例,在产前给予地塞米松注射;对照组44例,产前给予地塞米松+VitK1.两组早产儿各30例留取脐动脉血离心零下20℃以下保存用凝固法检测Ⅱ、Ⅶ、Ⅸ、Ⅹ等凝血因子活性水平,同时留取同期出生的健康足月新生儿30例脐血标本作对照.两组早产儿生后1周内常规作头颅超声检查以明确有无脑室周围-脑室内出血及其程度.结果早产儿与足月新生儿脐血VitK依赖因子活性水平分别为Ⅱ(25.6±9.5)%对(36.7±4.9)%,Ⅶ(59.0±17.7)%对(64.5±10.6)%,Ⅸ(24.7±8.9)%对(30.2±5.7)%,Ⅹ(30.2±5.0)%对(34.3±12.6)(P<0.05).母亲产前补充VitK1后其婴儿脐血VitK依赖因子水平分别为Ⅱ(36.4±6.9)%,Ⅶ(69.6±16.6)%,Ⅸ(25.7±10.9)%和Ⅹ(39.3±8.0)%,除Ⅸ因子外,Ⅱ、Ⅶ和Ⅹ因子活性均显著升高(P<0.05).脑室周围-脑室内出血发生率在对照组为52.6%,观察组为31.8%(χ2=5.744,P=0.017);重度出血对照组为12.0%,观察组为2.3%(χ2=3.626,P=0.057).结论早产儿存在VitK依赖因子水平低下,可能为其易于发生脑室周围-脑室内出血的原因之一.分娩前母亲补充VitK1可显著提高其血浆Ⅱ、Ⅶ和Ⅹ因子水平,并对脑室周围-脑室内出血有一定的预防作用.     

Bone mineral content, serum vitamin D metabolite concentrations, and ultraviolet B light exposure in infants fed human milk with and without vitamin D2 supplements

OBJECTIVE: To monitor ultraviolet B light exposure in human milk-fed infants both with and without supplemental vitamin D2, and to measure longitudinally the bone mineral content, growth, and serum concentrations of calcium, phosphorus, 25-hydroxyvitamin D3, 25-hydroxyvitamin D2, 1,25-dihydroxyvitamin D, and parathyroid hormone. DESIGN: Longitudinal, randomized, double-blind, placebo-controlled study of 6 months' duration. SETTING: Patients from private pediatric practice, Madison, Wisconsin. PATIENTS: Sequential sampling of 46 human milk-fed white infants; 24 received 400 IU/day of vitamin D2, and 22 received placebo. An additional 12 patients were followed who received standard infant formula. Eighty-three percent of patients completed a full 6 months of the study. MEASUREMENTS and RESULTS: Ultraviolet B light exposure and measurements of growth did not differ between groups. At 6 months, the human milk groups did not differ significantly in bone mineral content or serum concentrations of parathyroid hormone or 1,25-dihydroxyvitamin D, although total 25-hydroxyvitamin D values were significantly less in the unsupplemented human milk group (23.53 +/- 9.94 vs 36.96 +/- 11.86 ng/ml; p less than 0.01). However, 25-hydroxyvitamin D3 serum concentrations were significantly higher in the unsupplemented human milk-fed group compared with the supplemented group (21.77 +/- 9.73 vs 11.74 +/- 10.27 ng/ml, p less than 0.01) by 6 months of age. CONCLUSION: Unsupplemented, human milk-fed infants had no evidence of vitamin D deficiency during the first 6 months of life.     

The influence of maternal body mass index on infant adiposity and hepatic lipid content

Maternal overweight and obesity are associated with adverse offspring outcome in later life. The causal biological effectors are uncertain. Postulating that initiating events may be alterations to infant body composition established in utero, we tested the hypothesis that neonatal adipose tissue (AT) content and distribution and liver lipid are influenced by maternal BMI. We studied 105 healthy mother-neonate pairs. We assessed infant AT compartments by whole body MR imaging and intrahepatocellular lipid content by H MR spectroscopy. Maternal BMI ranged from 16.7 to 36.0. With each unit increase in maternal BMI, having adjusted for infant sex and weight, there was an increase in infant total (8 mL; 95% CI, 0.09-14.0; p = 0.03), abdominal (2 mL; 95% CI, 0.7-4.0; p = 0.005), and nonabdominal (5 mL; 95% CI, 0.09-11.0; p = 0.054) AT, and having adjusted for infant sex and postnatal age, an increase of 8.6% (95% CI, 1.1-16.8; p = 0.03) in intrahepatocellular lipid. Infant abdominal AT and liver lipid increase with increasing maternal BMI across the normal range. These effects may be the initiating determinants of a life-long trajectory leading to adverse metabolic health.     

Vitamin K status of lactating mothers, human milk, and breast-feeding infants

Hemorrhagic disease of the newborn is a disease of breast-feeding newborns. There is little information on longitudinal breast milk concentrations of phylloquinone (vitamin K1) or the effects of maternal phylloquinone supplements on breast milk. In study part 1, 11 lactating mothers, who received 20 mg of phylloquinone orally, had rises in plasma (less than 1 to 64.2 +/- 31.5 ng/mL by 6 hours) and breast milk concentrations (from 1.11 +/- 0.82 to 130 +/- 188 ng/mL by 12 hours). In part 2, 23 lactating mothers and their infants were observed longitudinally along with a formula-fed control group of infants (n = 11). Mean breast milk concentrations of phylloquinone at 1, 6, 12, and 26 weeks were 0.64 +/- 0.43, 0.86 +/- 0.52, 1.14 +/- 0.72, and 0.87 +/- 0.50 ng/mL, respectively, in the infants fed human milk. Maternal phylloquinone intakes (72-hour dietary recalls) exceeded the recommended daily allowance of 1 microgram/kg per day. Infant phylloquinone intakes did not achieve the recommended daily allowance of 1 microgram/kg per day in any infant. Plasma phylloquinone concentrations in the infants fed human milk remained extremely low (mean less than 0.25 ng/mL) throughout the first 6 months of life compared with the formula-fed infants (4.39 to 5.99 ng/mL). In this small sample, no infant demonstrated overt vitamin K deficiency. Despite very low plasma phylloquinone concentrations, vitamin K supplements (other than in the immediate newborn period) cannot be recommended for exclusively breast-fed infants based on these data.     

Breast-feeding among teenage mothers: milk composition, infant growth, and maternal dietary intake

Information on breast-feeding was obtained from 25 mothers recruited from four high school programs for teenaged parents. Subjects were visited monthly 1-9 times (mean 3.7 visits) during the first 10 months of lactation to measure infant growth and maternal dietary intake and to collect a breast milk sample. Of 24 mothers visited more than once, 21 (88%) breast-fed for more than 3 months, and at least nine continued beyond 6 months. Compared to the nutrient content of milk samples from adult women, milk of teenage mothers was significantly lower in lactose, magnesium, calcium, potassium, and sodium. However, the differences in magnesium, calcium, and potassium may have been due to differences in the timing of sample collection. On the basis of infant growth, milk volume was judged to be adequate for 88% of the infants. Mean maternal energy and protein intakes were 2,897 kcal and 115 g, respectively; mean intakes of calcium, potassium, vitamin A, riboflavin, niacin, and vitamin C exceeded the National Research Council's Recommended Dietary Allowances (RDA) for lactation, while iron and thiamine intakes averaged 84% and 94% of the RDA, respectively. It is concluded that with active counseling teenage mothers are capable of successful lactation.     

Influences of maternal dietary intake and suckling on breast milk lipid and fatty acid composition in low-income women from Brasilia, Brazil

Diet has a strong effect, while suckling stimulus is believed not to influence breast milk fatty acids. The effect of dietary pattern and suckling on the fatty acid composition of Brazilian women's breast milk was studied. A cross-sectional study was conducted with low-income women living in the central region of Brazil, where dietary DHA is not readily available. Fore and hind milk fatty acids were collected from 77 women on day 15+/-1 postpartum, and information on maternal characteristics and dietary habit was taken. The effect of suckling stimulus was measured by the changes between fore and hind milk. The mean body mass index (BMI) of volunteers was 23.7+/-3.2 kg/m(2), and the milk lipid concentration was 4.8+/-1.2 g/dl. A mixture of traditional and western type of dietary habit, high in fat and sugar was observed. The fatty acids of the subject's milk were 41.93+/-1.42% saturated, 33.31+/-1.67% monounsaturated and 25.03+/-5.23% polyunsaturated (wt/wt). The DHA level in the milk was 0.34+/-0.19%, similar to the values found in milk of many western societies. DHA and 18:3n-3 levels increased from fore to hind milk (p<0.05). Correlation existed mostly between dietary components and milk 16:0 and oleic acid (18:0). An analysis of classes of fatty acids in milk showed oleic acid (18:0) to present a negative correlation with all milk fatty acid classes. The results suggest that breast milk fatty acids of Brazilian women reflect a western maternal dietary pattern and are influenced by the suckling.     

Longitudinal study of vitamins A, E and lipid oxidative damage in human milk throughout lactation

Background

Little is known about the intensity of oxidative damage in human milk resulting from maternal oxidative stress. The aim of our study was to explore the changes in Total Antioxidant Status (TAS) and concentrations of antioxidative vitamins and isoprostanes (markers of oxidative stress) in human colostrum and mature milk.

Methods

The study included 49 postpartum women with normal, spontaneous full term delivery. The exclusion criteria included active and passive smoking, acute and chronic disorders, and pharmacotherapy other than vitamin supplementation. Colostrum samples were collected on the 3rd day after delivery and breast milk samples between the 30th and the 32nd day after delivery. TAS of colostrum/breast milk was determined by Rice-Evans and Miller method. The amount of vitamins A and E was measured by HPLC. Isoprostane concentrations in colostrum/mature milk and urine were determined immunoenzymatically.

Results

No significant differences were observed in maternal dietary intakes of vitamins A and E determined prior to the colostrum and mature milk sampling. The TAS of mature milk was significantly higher compared to colostrum (P = 0.002), while vitamin A and E concentrations were significantly lower (P = 0.003 and P = 0.001). Although the isoprostane concentration of mature milk was significantly higher than the colostrum concentration, this difference was not significant (P = 0.129).

Conclusion

Human milk is a source of antioxidative vitamins and their concentrations decrease throughout the lactation, while their total antioxidative properties increase. The phase of lactation does not affect the degree of human milk's lipid oxidative damage.     

Energy and respiratory metabolism in cystic fibrosis: the influence of carbohydrate content of nutritional supplements

The basal energy expenditure (BEE) in a group of adolescent and young adult patients with cystic fibrosis (CF) with mild lung disease was 97 +/- 6% of that predicted by the Harris-Benedict equation (which estimates BEE by age, sex, height, and weight). The BEE of a group with more severe lung disease was 117 +/- 5% of that predicted by the Harris-Benedict equation, due primarily to a 14% greater oxygen consumption (VO2) and 24% greater CO2 production (VCO2) compared with milder lung disease (p less than 0.05). The measured BEE in the patients with mild lung disease correlated well with the predicted BEE, but variably underestimated that of patients with more advanced lung disease. The influence of low carbohydrate (Pulmocare) and higher carbohydrate (Instant Breakfast) nutritional supplements on the energy and pulmonary metabolism was compared in 10 malnourished CF patients with moderate to severe lung disease. Their BEE before ingesting the supplements was 120% of that predicted by the Harris-Benedict equation. Their VCO2 increased 9-19% for the 3 h after ingesting 500 kcal/M2 of Pulmocare, and 25-30% after ingesting Instant Breakfast (p less than 0.05). The respiratory quotient (RQ) was significantly greater for Instant Breakfast than Pulmocare. The minute ventilation (VE) rose 10-13% for the 3 h after ingesting Pulmocare, versus 27-31% after ingesting Instant Breakfast, but the difference was not significant. The metabolic expenditure rose 13-16% for the 3 h after ingesting both formulas. We concluded that CF patients have increasing difficulty maintaining their nutrition as their pulmonary disease progresses, in part because of a 17-20% increase in their BEE.(ABSTRACT TRUNCATED AT 250 WORDS)