Incidence and correlates of breast milk feeding in hospitalized preterm infants

The majority of epidemiological studies of breast feeding have been conducted in healthy, fullterm infant samples. Little is known about the incidence and correlates of breast milk feeding in preterm infants, particularly in those born outside of metropolitan areas. Therefore, hospital medical charts of 151 consecutively admitted preterm infants (相似文献   

Nitrate and nitrite levels in fruity and natural mineral waters marketed in western Turkey

Nitrate and nitrite levels in our natural water supplies are important indicators of water quality. The increasing levels of nitrate and nitrite concentrations are becoming an important problem for public health. Nitrates are of great toxicological concern as they are involved in the origin of nitrites and nitrosamines and the development of metahaemoglobinaemia in infants. The aim of this study was to determine the levels of nitrate and nitrite in commonly consumed mineral water samples in the Afyonkarahisar region of western Turkey. Thirteen brands of domestic fruity and natural mineral waters were analyzed to determine nitrate and nitrite levels. Measurement of the color intensity was carried out using a photometry at 540 nm and comparing it to standard nitrate and nitrite solutions. Average nitrate concentrations of 3.093±1.53 mg/L (range 1.02–7.50 mg/L) for fruity, and 3.990±2.46 mg/L (range 1.09–13.20 mg/L) for natural mineral waters, were detected. Regarding nitrite, average concentrations were 0.020±0.007 mg/L (range 0.009–0.049 mg/L) for fruity and 0.026±0.008 mg/L (range 0.008–0.087 mg/L) for natural mineral waters. According to the results of the present study, nitrate and nitrite levels in the fruity and natural mineral waters were not found in concentrations considered to be hazardous in terms of public health.     

Alterations of nitrite and nitrate concentrations in the blood of mice exposed to nitrogen dioxide

Blood nitrite and nitrate of mice were determined using naphthylethylenediamine and a Cu-Cd reduction column. When mice were exposed to 40 ppm nitrogen dioxide, nitrite became constant in 10 min. Nitrite declined rapidly, with a half-life of several minutes, when mice were removed to room air. Nitrate showed changes similar to those of nitrite; however, the concentration in the blood was higher and the half-life was longer. Dose-effect relationships were also determined at concentrations ranging between 5 and 40 ppm for 1 hr exposure. No increase of methemoglobin was observed at these concentrations. Addition of fresh mouse blood to sodium nitrite in vitro indicated a rapid conversion of nitrite to nitrate with an increase of methemoglobin, whereas addition to sodium nitrate did not cause any changes. The fate of inhaled nitrogen dioxide in the living body is discussed based on the results obtained.     

Lactoferrin Levels in Term and Preterm Milk

Objective: Even though there is no doubt that human milk is the best nourishment for the neonate, there is still controversy regarding its suitability for preterm infants. The aim of this study was to contribute to the knowledge of the anti-infective properties of preterm milk, measuring lactoferrin levels, which are a non-specific protective factor.

Methods: Samples from 26 preterm and 20 term mothers (mean gestational age±standard deviation, 30.9±2.6 and 39.5±1.1 weeks, respectively) were collected during the first month post-partum. Milk samples were obtained by total expression of one breast between 10 a.m. and noon. An aliquot was kept at ?20°C until analyzed by SDS-PAGE (sodium dodecyl sulfate-polyacrylarnide gel electrophoresis). Each sample was run in duplicate.

Results: Lactoferrin levels (X±SD) in colostrum and mature milk varied from 575.0±218.2 mg/dL to 459.4±190.7 mg/dL in preterm samples and from 970.6±288.6 mg/dL to 292.0±167.4 mg/dL in term samples. No significant differences were observed between preterm and term groups, in spite of the trend observed in colostrum, where term milk tended to show higher levels than preterm milk. Decreasing values were observed in both groups along time (ANOVA, p<0.05). However, in the preterm group, lactoferrin levels seemed to maintain rather constant values from the eighth post-partum day onwards.

Conclusions: The trend to higher levels of lactoferrin in preterm mature milk would allow maintenance of the protective effect of human milk in preterm infants in spite of the small volumes ingested by these neonates. These findings support the practice of feeding premature infants with their own mothers’ milk at a time when their immune systems have not completely developed.     

牛乳与乳粉中亚硝酸盐和硝酸盐的固相萃取离子色谱测定法

目的建立离子色谱同时测定牛乳与乳粉中亚硝酸盐和硝酸盐含量的方法。方法采用甲醇-乙腈对样品进行萃取并离心,上清液经C18小柱净化后,利用IonPac AS 11—HC柱分离和电导检测器测定,外标法定量。结果亚硝酸盐:线性范围0.02～0.20 mg/L,相关系数0.999 5,样品加标回收率90.0%～104.8%,RSD 3.5%,检出限为牛乳0.002 mg/kg,乳粉0.006 mg/kg;硝酸盐:线性范围0.20～2.0 mg/L,相关系数0.999 4,样品加标回收率90.0～105.8%,RSD 2.3%,检出限为牛乳0.006 mg/kg,乳粉0.03 mg/kg。结论该方法简便,快速,适合牛乳与乳粉中亚硝酸盐和硝酸盐含量的测定。     

Milk feeding and dietary patterns predict weight and fat gains in infancy

Current guidelines recommend that infants are exclusively breast fed for the first 6 months of life, with particular solid foods being gradually introduced from 6 months. Our objective was to compare the growth of infants whose feeding most closely followed current guidelines with the growth of infants with other feeding practices. Participants were 1740 infants in a prospective cohort study in Southampton, UK. At 6 and 12 months, infants’ milk feeding was recorded, diets assessed using food frequency questionnaires (FFQ), and anthropometry performed. Principal components analysis was used to identify patterns of foods in the diet using the food intakes assessed by the FFQs. Two patterns (‘infant guidelines’ and ‘adult foods’) explained most variance in infant diet at 6 and 12 months of age. The main outcomes were conditional growth in weight, length and skinfold thickness from 0–6 and 6–12 months. Infants who were breast fed from 0–6 months gained weight, length and adiposity more slowly than formula‐fed infants, independent of age at introduction of solids and maternal factors: compared with infants who were breast fed from 0–6 months, formula‐fed infants gained 0.21 standard deviation scores (SDS) in weight [95% confidence interval (CI) 0.00, 0.42]. Infants whose dietary pattern was most similar to current feeding guidelines, with high frequencies of fresh fruit and vegetables, home‐prepared foods and breast milk, gained weight and skinfold thickness more rapidly from 6 to 12 months than other infants, independent of milk feeding, age at introduction of solids and maternal factors. Compared with infants in the lowest quarter, infants in the highest ‘infant guidelines’ score quarter gained 0.24 SDS [95% CI 0.06, 0.43] in weight and 0.26 SDS [95% CI 0.07, 0.45] in skinfold thickness. Conversely, infants whose diets had the highest frequencies of breads and processed foods gained weight less rapidly from 6 to 12 months than other infants. The extent to which the patterns of diet and growth we have described will influence the current or later health of infants is unknown. We are following up the infants in this study to assess the impact of these patterns beyond the first year of life. These associations should also be examined in other settings and populations.     

Using Nature to Nurture: Breast Milk Analysis and Fortification to Improve Growth and Neurodevelopmental Outcomes in Preterm Infants

Premature infants are born prior to a critical window of rapid placental nutrient transfer and fetal growth—particularly brain development—that occurs during the third trimester of pregnancy. Subsequently, a large proportion of preterm neonates experience extrauterine growth failure and associated neurodevelopmental impairments. Human milk (maternal or donor breast milk) is the recommended source of enteral nutrition for preterm infants, but requires additional fortification of macronutrient, micronutrient, and energy content to meet the nutritional demands of the preterm infant in attempts at replicating in utero nutrient accretion and growth rates. Traditional standardized fortification practices that add a fixed amount of multicomponent fortifier based on assumed breast milk composition do not take into account the considerable variations in breast milk content or individual neonatal metabolism. Emerging methods of individualized fortification—including targeted and adjusted fortification—show promise in improving postnatal growth and neurodevelopmental outcomes in preterm infants.     

婴儿血铅与母亲血铅和乳铅等因素的相关性研究

目的了解婴儿血铅与母亲血铅和乳铅等因素的相关关系,为防治儿童铅中毒提供参考依据。方法2002年11至12月,采用石墨炉原子吸收光谱法,测定厦门市177名0～11个月的婴儿及其母亲的血铅,并对小儿出生情况及其母亲、家庭环境等相关因素进行问卷调查。结果177例婴儿血铅的几何均值为(0.37±0.15)μmol/L,范围为0.12～1.36μmol/L,≥0.48μmol/L者46例(占25.99%);母亲血铅的均值为(0.50±0.14)μmol/L,范围为0.21～2.38μmol/L;177例中有160例为母乳喂养儿,其中105例采集出乳汁,乳铅的几何均值为(0.17±0.08)μmol/L,婴儿血铅与母亲的血铅和乳铅密切相关,表明母体的铅可以通过乳汁影响到婴儿血铅水平。旧商业区婴儿的血铅、婴儿母亲乳铅水平均高于其他地区,婴儿血铅水平主要与母亲血铅、婴儿月龄和母亲在职等呈正相关关系,而与母亲身高等因素呈负相关关系。结论母乳喂养儿的血铅水平除了与母亲血铅水平相关外,还与乳铅密切相关,因此在婴儿喂养方式的选择和家庭抚育行为方面须引起重视。     

Serum T4 level in term newborns: Comparison between breast-fed and formula-fed infants

Serum thyroxine measurement ([¹²⁵I] T₄-RIA) was performed on the third day of life in 1759 normal, full-term infants. The T₄ concentrations were similar in the 680 formula-fed infants (16.32±0.09 μg/dl) and in the 1079 breast-fed infants (16.46±0.08 μg/dl). A male breast-fed infant was discovered to have hypo-TBG-emia. Our findings show that breast feeding from birth will not interfere with neonatal screening for hypothyroxinemia on the third day of life. Additionally, the mean T₄ value in the formulafed males was significantly lower than the breast-fed males, (15.88±0.13 μg/dl vs 16.32±0.11 μg/dl, p<0.01). Also, the formula-fed males has a significantly lower (p<0.01) T₄ concentration when compared with the formula-fed females.     

Concentration and distribution of sialic acid in human milk and infant formulas

BACKGROUND: In animal studies, sialic acid supplementation is associated with increases of gangliosides in the brain and improved learning ability. Only limited data are available on the sialic acid content of human milk and infant formulas. OBJECTIVE: We compared the concentrations of oligosaccharide-bound, protein-bound, and free sialic acid in milk from mothers of full-term and preterm infants and in a range of infant formulas. DESIGN: The milk from 20 and 14 mothers of full-term and preterm infants (mean gestational age: 31 +/- 3 wk), respectively, was collected at 4 stages of lactation (colostrum, transition, 1 mo, and 3 mo) and compared with 21 different infant formulas. RESULTS: Total sialic acid concentrations were highest in colostrum (x +/- SEM: 5.04 +/- 0.21 mmol/L in full term) and decreased by nearly 80% over the next 3 mo. Human milk from mothers of preterm infants contained 13-23% more sialic acid than did milk from mothers of full-term infants at 3 of the 4 lactation stages (P < 0.02). The sialic acid content of most formulas was <25% of that found in mature human milk (P < 0.01). Most of the sialic acid in the formulas ( approximately 70%) was bound to glycoproteins, whereas in human milk most sialic acid was bound to free oligosaccharides. CONCLUSIONS: Human milk, including milk from mothers of preterm infants, is a rich source of oligosaccharide-bound sialic acid, which contrasts with the relatively small amounts found in infant formulas. The nutritional significance of sialic acid is presently unknown, but it is plausible that it is a conditional nutrient that contributes to sialic acid accretion in the brain.     

A Nitrate-Rich Vegetable Intervention Elevates Plasma Nitrate and Nitrite Concentrations and Reduces Blood Pressure in Healthy Young Adults

BackgroundEmerging evidence suggests that increasing dietary nitrate intake may be an effective approach to reduce blood pressure. Beetroot juice is often used to supplement dietary nitrate, whereas nitrate intake levels from habitual diet are low. An increase in the habitual intake of nitrate-rich vegetables may represent an alternative to nitrate supplementation. However, the effectiveness and acceptability of a nitrate–rich-vegetables diet remain to be established.ObjectiveThe aim was to investigate the effect and feasibility of two different intervention strategies to increase dietary nitrate intake, on plasma nitrate/nitrite concentrations and blood pressure.DesignA randomized, crossover trial was used.ParticipantsParticipants were healthy men and women (both n=15; age: 24±6 years) from the Netherlands.InterventionParticipants were instructed to consume ∼400 mg nitrate at lunch, provided through nitrate-rich vegetables and dietary counseling, or beetroot juice supplementation. Both interventions lasted 1 week, with 1-week washout (January to April 2017).Main outcomePlasma nitrate and nitrite concentrations and resting systolic and diastolic blood pressure were measured in an overnight fasted state (before and after intervention) and ∼2.5 hours after lunch (before and throughout intervention on day 1, 4, and 7).Statistical analysisTwo-factor (time × treatment) repeated-measures analyses of variance were performed.ResultsMean plasma nitrate concentrations increased with both interventions, with a larger increase in beetroot juice vs nitrate-rich vegetables, both in a fasted state and ∼2.5 hours after lunch (day 1, beetroot juice: 2.31±0.56 mg/dL [373±90 μmol/L] vs nitrate-rich vegetables: 1.71±0.83 mg/dL [277±134 μmol/L]; P<0.001). Likewise, mean plasma nitrite concentrations increased with both interventions, but were higher after lunch in beetroot juice than in nitrate-rich vegetables (day 1: 2.58±1.52 μg/dL [560±331 nmol/L] vs 2.15±1.21 μg/dL [468±263 nmol/L]; P=0.020). Fasting mean systolic and diastolic blood pressure did not change, but mean systolic and diastolic blood pressure assessed ∼2.5 hours after lunch were significantly reduced throughout both intervention periods (P<0.05), with no differences between beetroot juice and nitrate-rich vegetables (day 1, systolic blood pressure: –5.1±9.5 mm Hg and diastolic blood pressure: –5.3±8.9 mm Hg).ConclusionShort-term consumption of dietary nitrate in the form of nitrate-rich vegetables represents an effective means to increase plasma nitrate and nitrite concentrations, and reduces blood pressure to the same extent as beetroot juice supplementation.     

Visual development of human milk-fed preterm infants provided with extra energy and nutrients after hospital discharge

Background: Human milk (HM) is the optimal way to nourish preterm low birth weight (LBW) infants after hospital discharge. However, there are few data on which to assess whether HM alone is sufficient to address hospital‐acquired nutrition deficits, and no adequately powered studies have examined this question using neurodevelopment as an outcome. The purpose of this work was to determine whether adding extra energy and nutrients to the feedings of predominantly HM‐fed LBW infants early after discharge improves their visual development. Visual development was used in this study as a surrogate marker for neurodevelopment. Methods: At discharge, 39 predominantly HM‐fed LBW infants (750–1800 g, 1288 ± 288 g) were randomized to receive human milk alone (control) or around half of the HM received daily mixed with a multinutrient fortifier (intervention) for 12 weeks. Grating acuity (ie, visual acuity) and contrast sensitivity were assessed using sweep visual‐evoked potential tests at 4 and 6 months corrected age. Results: At 4 and 6 months corrected age, intervention infants demonstrated higher grating acuity compared to those in the control group (intervention: 7.8 ± 1.3 and 9.7 ± 1.2 [cycles/degree] vs control 6.9 ± 1.2 and 8.2 ± 1.3, P = .02). Differences in contrast sensitivity did not reach statistical significance (P = .11). Conclusion: Adding a multinutrient fortifier to a portion of the expressed breast milk provided to predominantly HM‐fed LBW infants early after discharge improves their early visual development. Whether these subtle differences in visual development apply to other aspects of development or longer term neurodevelopment are worthy of future investigation.     

Relationships of lead in breast milk to lead in blood, urine, and diet of the infant and mother.

We have obtained stable lead isotope and lead concentration data from a longitudinal study of mobilization of lead from the maternal skeleton during pregnancy and lactation and in which the newly born infants were monitored for 6 months postpartum to evaluate the effects of the local environment on lead body burden of the infant. Samples of maternal and infant blood, urine, and diet and especially breast milk were measured for 21 mothers and 24 infants. Blood lead concentrations were less than 5 microg/dl in all except one subject. The mean lead concentration in breast milk +/- standard deviation was 0.73 +/- 0.70 microg/kg. In seven subjects for whom serial breast milk sampling was possible, the lead concentration varied by factors of from 2 to 4, and for three subjects there was an increase at or after 90 days postpartum. For the first 60-90 days postpartum, the contribution from breast milk to blood lead in the infants varied from 36 to 80%. Multiple linear regression analyses indicated statistically significant relationships for some of the variables of isotope ratios and lead concentrations between breast milk, blood, urine, and diet for infants and mothers. For example, the analyses revealed that both a mother's breast milk 207Pb/206Pb and 206Pb/204Pb ratios and lead concentration provide information to predict her infant's blood 207Pb/206Pb and 206Pb/204Pb ratios. The major sources of lead in breast milk are from the maternal bone and diet. An evaluation of breast milk lead concentrations published over the last 15 years indicates that studies in which the ratio of lead concentrations in breast milk to lead concentrations in whole maternal blood (Multiple>100) were greater than 15 should be viewed with caution because of potential contamination during sampling and/or laboratory analyses. Selected studies also appear to show a linear relationship between breast milk and maternal whole blood, with the percentage of lead in breast milk compared with whole blood of <3% in subjects with blood lead levels ranging from 2 to 34 microgram/dl. The levels of lead in breast milk are thus similar to those in plasma. Breast-fed infants are only at risk if the mother is exposed to high concentrations of contaminants either from endogenous sources such as the skeleton or exogenous sources.     

Transmission of methicillin-resistant Staphylococcus aureus to preterm infants through breast milk.

OBJECTIVE: To determine a potential source of MRSA colonization and infection among preterm infants in a neonatal intensive care unit (NICU) using molecular analysis of breast milk samples. DESIGN: Case report, outbreak investigation. RESULTS: Preterm triplets were delivered at 26 weeks' gestation via cesarean section when routine active surveillance for MRSA was performed for all infants in a NICU. Surveillance consisted of swabbing the throat, nose, and umbilicus (TNU) weekly. Although infants A and B initially had negative TNU swabs, repeat cultures were positive for MRSA on day of life (DOL) 10 and DOL 18, respectively. Surveillance and clinical cultures for infant C were negative. Infant A developed sepsis, and multiple blood cultures were positive for MRSA beginning on DOL 14. Infant B developed conjunctivitis and a conjunctival exudate culture was positive for MRSA on DOL 70. Both infants were fed breast milk via nasogastric tube. Cultures of breast milk samples for infants A and B dated prior to either infant's first positive surveillance culture were positive for MRSA. All MRSA isolates had identical results on antibiotic susceptibility testing. PFGE demonstrated identical banding patterns for the MRSA isolates from the blood culture of infant A, breast milk for infants A and B, and a surveillance swab from infant B. At no time did the mother develop evidence of mastitis or other local breast infection. CONCLUSIONS: MRSA can be passed from mother to preterm infant through contaminated breast milk, even in the absence of maternal infection. Colonization and clinical disease can result.     

From Mum to Bum: An Observational Study Protocol to Follow Digestion of Human Milk Oligosaccharides and Glycoproteins from Mother to Preterm Infant

The nutritional requirements of preterm infants are challenging to meet in neonatal care, yet crucial for their growth, development and health. Aberrant maturation of the gastrointestinal tract and the microbiota could affect the digestion of human milk and its nutritional value considerably. Therefore, the main objective of the proposed research is to investigate how the intestinal microbiota of preterm and full-term infants differ in their ability to extract energy and nutrients from oligosaccharides and glycoproteins in human milk. This pilot study will be an observational, single-center study performed at the Neonatal Intensive Care Unit at Isala Women and Children’s Hospital (Zwolle, The Netherlands). A cohort of thirty mother–infant pairs (preterm ≤30 weeks of gestation, n = 15; full-term 37–42 weeks of gestation, n = 15) will be followed during the first six postnatal weeks with follow-up at three- and six-months postnatal age. We will collect human milk of all mothers, gastric aspirates of preterm infants and fecal samples of all infants. A combination of 16S rRNA amplicon sequencing, proteomics, peptidomics, carbohydrate analysis and calorimetric measurements will be performed. The role of the microbiota in infant growth and development is often overlooked yet offers opportunities to advance neonatal care. The ‘From Mum to Bum’ study is the first study in which the effect of a preterm gut microbiota composition on its metabolic capacity and subsequent infant growth and development is investigated. By collecting human milk of all mothers, gastric aspirates of preterm infants and fecal samples of all infants at each timepoint, we can follow digestion of human milk from the breast of the mother throughout the gastrointestinal tract of the infant, or ‘From Mum to Bum’.     

Nitrate, nitrite balance, and de novo synthesis of nitrate in humans consuming cured meats

Nitrate balance was measured in nine men consuming a fixed daily diet with constant nitrate (570 mumol/day), varying nitrite (18 to 150 mumol/day), and varying erythorbate levels. Nitrite and erythorbate were added to meat that was then cured and frozen until consumption. All diets were consumed by each subject for 17 days each. Average daily urinary nitrate excretion ranged from 959 to 2382 mumol/day. Subjects excreted significantly more nitrate in urine when fed nitrite cured meats with or without erythorbate than when fed uncured meat (1617 and 1577 versus 1430 mumol nitrate/day, respectively). The amount of nitrate excreted in urine consistently exceeded intakes of nitrate and nitrite by an average 870 mumol/day. This excess represented endogenous synthesis by subjects and was not due to unmeasured nitrate in the diet. The commonly used Greiss and xylenol procedures were unable to measure all nitrate in urine and in diets when compared to high performance liquid chromatographic analyses. The Greiss and xylenol analyses underestimated nitrate synthesis by 220 and 150 mumol/day, respectively when results were not adjusted by determining recovery of added nitrate.     

Untargeted Metabolomic Analysis of Human Milk from Mothers of Preterm Infants

The application of metabolomics in neonatology offers an approach to investigate the complex relationship between nutrition and infant health. Characterization of the metabolome of human milk enables an investigation into nutrients that affect the neonatal metabolism and identification of dietary interventions for infants at risk of diseases such as necrotizing enterocolitis (NEC). In this study, we aimed to identify differences in the metabolome of breast milk of 48 mothers with preterm infants with NEC and non-NEC healthy controls. A minimum significant difference was observed in the human milk metabolome between the mothers of infants with NEC and mothers of healthy control infants. However, significant differences in the metabolome related to fatty acid metabolism, oligosaccharides, amino sugars, amino acids, vitamins and oxidative stress-related metabolites were observed when comparing milk from mothers with control infants of ≤1.0 kg birth weight and >1.5 kg birth weight. Understanding the functional biological features of mothers’ milk that may modulate infant health is important in the future of tailored nutrition and care of the preterm newborn.     

Plasma Nitrate and Nitrite Kinetics after Single Intake of Beetroot Juice in Adult Patients on Chronic Hemodialysis and in Healthy Volunteers: A Randomized,Single-Blind,Placebo-Controlled,Crossover Study

Nitric oxide (NO) contributes to maintaining normal cardiovascular and renal function. This bioactive signalling molecule is generally formed enzymatically by NO synthase in the vascular endothelium. NO bioactivity can also be attributed to dietary intake of inorganic nitrate, which is abundant in our diet, especially in green leafy vegetables and beets. Ingested nitrate is reduced to nitrite by oral commensal bacteria and further to NO systemically. Previous studies have shown that dialysis, by means of removing nitrate and nitrite from the body, can reduce NO bioactivity. Hence, dietary intervention approaches aimed to boost the nitrate–nitrite–NO pathway may be of benefit in dialysis patients. The purpose of this study was to examine the kinetics of plasma nitrate and nitrite after a single intake of nitrate-rich concentrated beetroot juice (BJ) in adult hemodialysis (HD) patients and in age-matched healthy volunteers (HV). Eight HD patients and seven HV participated in this single center, randomized, single-blind, placebo-controlled, crossover study. Each participant received a sequential single administration of active BJ (70 mL, 400 mg nitrate) and placebo BJ (70 mL, 0 mg nitrate) in a random order separated by a washout period of seven days. For the kinetic analysis, blood samples were collected at different time-points before and up to 44 h after BJ intake. Compared with placebo, active BJ significantly increased plasma nitrate and nitrite levels both in HD patients and HV. The area under the curve and the maximal concentration of plasma nitrate, but not of nitrite, were significantly higher in HD patients as compared with HV. In both groups, active BJ ingestion did not affect blood pressure or plasma potassium levels. Both BJs were well tolerated in all participants with no adverse events reported. Our data provide useful information in planning dietary nitrate supplementation efficacy studies in patients with reduced NO bioactivity.     

Bioavailability of calcium and zinc from cow's milk-based versus soya-based infant food

A modified continuous flow dialysis in vitro method was used to study the availability of calcium and zinc from cow's milk-based versus soya-based infant food. First and second age infant formulae, milk for pre-schoolers and cow's milk were studied. The elemental content of the samples and dialysate fractions was determined by flame atomic absorption spectrometry. The relative availability of calcium and zinc from the soya-based first age infant formula (calcium: 31.6 ± 0.5%, zinc: 17.8 ± 1.8%), from the soya-based second age infant formula (calcium: 46.1 ± 2.1%, zinc: 20.9 ± 1.4%) and from the soya milk for pre-schoolers (calcium: 32.6 ± 0.7%, zinc: 39.7 ± 2.1%) proved to be as good as or even better than from the first age infant formula (calcium: 21.9 ± 1.4%, zinc: 23.3 ± 4.1%), from the second age infant formula (calcium: 31.0 ± 2.5%, zinc: 14.6 ± 0.7%) and from the milk for pre-schoolers (calcium: 27.7 ± 0.6%, zinc: 23.7 ± 2.8%) based on cow's milk. A similar relative availability from semi-skimmed cow's milk and soya milk was reported for calcium (31.5 ± 0.8% and 31.2 ± 1.7% respectively), as well as a much higher availability of zinc from soya milk than from cow's milk (55.7 ± 5.3% and 20.6 ± 3.0% respectively). Enrichment of soya milk with calcium results in a higher calcium availability (46.4 ± 1.9%), but a lower zinc availability (38.5 ± 2.6%) in comparison with the availability from non-enriched soya milk. The apparent absence of inhibitory effects of soya on the availability of calcium and zinc from infant food certainly is a positive finding for the about 10% of Belgian infants which are currently nourished with infant food based on derivatives of soya. According to these results no impaired calcium or zinc status should be feared for in this group of infants.