Effect of fortifying breast milk on gastric emptying

Osmolality of fortified donor human milk: An experimental study

BACKGROUND

We quantify the osmolality of human milk fortified with human milk fortifiers (HMFs), powder infant formulas and protein additives.

METHODS

Commercial liquid HMFs and powder infant formulas were added to pasteurized pooled donor human milk in triplicate and stirred. The osmolality of unfortified and fortified human milk at 22, 24, 26, 27, 28, and 30 kcal/oz (0.73, 0.8, 0.87, 0.9, 0.93, and 1 kcal/ml, respectively) was determined using freezing-point depression.

RESULTS

The osmolality of fortified human milk associated with energy density in a linear relationship regardless of the fortification strategies. Multiple liquid HMFs and every powder infant formula exceeded the osmolality threshold of 450 mOsm/kg H2 O within the energy densities tested.

CONCLUSION

The osmolality of fortified human milk is highly variable and should be considered when selecting a fortifying agent for human milk.

Review of paediatric gastrointestinal physiology relevant to the absorption of orally administered medicines

Despite much progress in regulations to improve paediatric drug development, there remains a significant need to develop better medications for children. For the design of oral dosage forms, a detailed understanding of the specific gastrointestinal (GI) conditions in children of different age categories and how they differ from GI conditions in adults is essential. Several review articles have been published addressing the ontogeny of GI characteristics, including luminal conditions in the GI tract of children. However, the data reported in most of these reviews are of limited quality because (1) information was cited from very old publications and sometimes low quality sources, (2) data gaps in the original data were filled with textbook knowledge, (3) data obtained on healthy and sick children were mixed, (4) average data obtained on groups of patients were mixed with data obtained on individual patients, and (5) results obtained using investigative techniques that may have altered the outcome of the respective studies were considered. Consequently, many of these reviews draw conclusions that may be incorrect. The aim of the present review was to provide a comprehensive and updated overview of the available original data on the ontogeny of GI luminal conditions relevant to oral drug absorption in the paediatric population. To this end, the PubMed and Web of Science metadatabases were searched for appropriate studies that examined age-related conditions in the oral cavity, esophagus, stomach, small intestine, and colon. Maturation was observed for several GI parameters, and corresponding data sets were identified for each paediatric age group. However, it also became clear that the ontogeny of several GI traits in the paediatric population is not yet known. The review article provides a robust and valuable data set for the development of paediatric in vitro and in silico biopharmaceutical tools to support the development of age-appropriate dosage forms. In addition, it provides important information on existing data gaps and should provide impetus for further systematic and well-designed in vivo studies on GI physiology in children of specific age groups in order to close existing knowledge gaps and to sustainably improve oral drug therapy in children.

Pre-operative fasting in children: A guideline from the European Society of Anaesthesiology and Intensive Care

Current paediatric anaesthetic fasting guidelines have recommended conservative fasting regimes for many years and have not altered much in the last decades. Recent publications have employed more liberal fasting regimes with no evidence of increased aspiration or regurgitation rates. In this first solely paediatric European Society of Anaesthesiology and Intensive Care (ESAIC) pre-operative fasting guideline, we aim to present aggregated and evidence-based summary recommendations to assist clinicians, healthcare providers, patients and parents. We identified six main topics for the literature search: studies comparing liberal with conservative regimens; impact of food composition; impact of comorbidity; the use of gastric ultrasound as a clinical tool; validation of gastric ultrasound for gastric content and gastric emptying studies; and early postoperative feeding. The literature search was performed by a professional librarian in collaboration with the ESAIC task force. Recommendations for reducing clear fluid fasting to 1 h, reducing breast milk fasting to 3 h, and allowing early postoperative feeding were the main results, with GRADE 1C or 1B evidence. The available evidence suggests that gastric ultrasound may be useful for clinical decision-making, and that allowing a 'light breakfast' may be well tolerated if the intake is well controlled. More research is needed in these areas as well as evaluation of how specific patient or treatment-related factors influence gastric emptying.

Multi-nutrient fortification of human milk for preterm infants

BACKGROUND

Human breast milk-fed preterm infants can accumulate nutrient deficits leading to extrauterine growth restriction. Feeding preterm infants with multi-nutrient fortified human milk could increase nutrient accretion and growth rates and improve neurodevelopmental outcomes. Concern exists, however, that multi-nutrient fortifiers are associated with adverse events such as feed intolerance and necrotising enterocolitis.

OBJECTIVES

To determine whether multi-nutrient fortified human milk, compared with unfortified human milk, affects important outcomes (including growth rate and neurodevelopment) of preterm infants without increasing the risk of adverse effects (such as feed intolerance and necrotising enterocolitis).

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL; 2019, Issue 9), MEDLINE via PubMed (1966 to 26 September 2019), Embase (1980 to 26 September 2019), and the Cumulative Index to Nursing and Allied Health Literature (CINAHL; 1982 to 26 September 2019). We searched clinical trials databases, conference proceedings, and reference lists of retrieved articles for randomised controlled trials and quasi-randomised trials.

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials that compared feeding preterm infants with multi-nutrient (protein and energy plus minerals, vitamins, or other nutrients) fortified human breast milk versus unfortified (no added protein or energy) breast milk.

DATA COLLECTION AND ANALYSIS

We used the standard methods of Cochrane Neonatal. Two review authors separately evaluated trial quality, extracted data, and synthesised effect estimates using risk ratios (RRs), risk differences, and mean differences (MDs). We assessed the certainty of the body of evidence at the outcome level using "Grading of Recommendations Assessment, Development and Evaluation" (GRADE) methods.

MAIN RESULTS

We identified 18 trials in which a total of 1456 preterm infants participated. These trials were generally small and methodologically weak. Meta-analyses provided low- to moderate-certainty evidence showing that multi-nutrient fortification of human milk increases in-hospital rate of weight gain (MD 1.76 g/kg/d, 95% confidence interval (CI) 1.30 to 2.22), body length (MD 0.11 cm/week, 95% CI 0.08 to 0.15), or head circumference (MD 0.06 cm/week, 95% CI 0.03 to 0.08) among preterm infants. Few data on growth and developmental outcomes assessed beyond infancy are available, and these do not show effects of multi-nutrient fortification. The data do not suggest other benefits or harms and provide low-certainty evidence suggesting effects of multi-nutrient fortification on the risk of necrotising enterocolitis in preterm infants (typical RR 1.37, 95% CI 0.72 to 2.63; 13 studies, 1110 infants).

AUTHORS' CONCLUSIONS

Feeding preterm infants with multi-nutrient fortified human breast milk compared with unfortified human breast milk is associated with modest increases in in-hospital growth rates. Evidence is insufficient to show whether multi-nutrient fortification has any effect on long-term growth or neurodevelopment.

Hydrogen peroxide promotes gastric motility in the newborn rat

BACKGROUND

When compared with infant formula, human milk enhances gastric emptying in preterm infants. Hydrogen peroxide (H₂O₂) is present in large quantities in human milk that has an antimicrobial role for the mother and infant. In vitro adult rat studies suggest that H₂O₂ facilitates gastric motor contraction. Hypothesizing that H₂O₂ enhances gastric motility, we investigated its effects on the newborn rat stomach tissue.

METHODS

Rat newborn and adult gastric fundic segments, or their smooth muscle cells, were used to evaluate the muscle response to H₂O₂ exposure. Tissue expression of Rho kinase 2 (ROCK-2; Western blot), its catalase activity, and H₂O₂ content (Amplex Red) were measured. H₂O₂ gastric mucosal diffusion was evaluated with Ussing chambers.

RESULTS

In both newborn and adult rats, H₂O₂ induced gastric muscle contraction and this response was attenuated by pre-incubation with the antioxidant melatonin. H₂O₂ passively diffused across the gastric mucosa. Its effect on the muscle was modulated via ROCK-2 activation and inhibited by melatonin.

CONCLUSION

H₂O₂, at a concentration similar to that of human milk, promotes gastric motility in the rat. To the extent that the present findings can be clinically extrapolated, the human milk H₂O₂ content may enhance gastric emptying in neonates.

Does the Post-Feeding Position Affect Gastric Residue in Preterm Infants?

BACKGROUND

Body position affects the gastric emptying rate and hence the amount of gastric residue.

OBJECTIVE

This study aims to analyze the effect of the post-feeding position of preterm infants on gastric residue.

MATERIALS AND METHODS

This experimental study was conducted in the neonatal intensive care unit (NICU) of a university hospital (İnönü University Turgut Özal Medical Center) in Eastern Turkey. The study included 40 preterm infants weighing less than 2,000 g, who were fed orogastrically. The preterm infants were sequentially placed in four positions and were fed before each change of position. The infants were sequentially placed in the right lateral, left lateral, supine, and prone positions; their gastric residues were measured with a nasogastric tube. The gastric residue was recorded in percentages at 30, 60, 120, and 180 minutes. Ethical principles were applied in all phases of the study.

RESULTS

The lowest mean gastric residue level was observed in the right lateral position at 30 minutes (58.16 ± 12.71%) and 60 minutes (33.97 ± 15.00%). The prone position showed the lowest mean gastric residue level (1.74 ± 1.08%), followed by the right lateral (3.06 ± 1.97%), supine (3.53 ± 2.18%), and left lateral position (5.14 ± 1.85%) at 120 minutes. The final measurements were taken at 180 minutes with the right lateral position showing the lowest mean gastric residue level (0.38 ± 0.34%).

CONCLUSION

The premature infants had similar lower levels of gastric residue in the right lateral and prone positions and higher levels of gastric residue in left lateral and supine positions. The gastric emptying rate was found to be highest in the right lateral position at 30, 60, and 180 minutes and in the prone position at 120 minutes.

Trend of Nutritional Support in Preterm Infants

Without appropriate nutritional support, preterm infants fail to grow after birth and have malnutrition. The main reason for delayed feeding is fear of immaturity of gastrointestinal function. The principles of nutritional practice should be as follows: (1) minimal early initiation of enteral feeding with breast milk (0.5-1 mL/h) to start on Day 1 if possible and gradual increase as tolerated; (2) early aggressive parenteral nutrition as soon as possible; (3) provision of lipids at rates that will meet the additional energy needs of about 2-3 g/kg/d; and (4) attempt to increase enteral feeding rather than parenteral nutrition.

Multi-nutrient fortification of human milk for preterm infants

BACKGROUND

Exclusively breast milk-fed preterm infants may accumulate nutrient deficits leading to extrauterine growth restriction. Feeding preterm infants with multi-nutrient fortified human breast milk rather than unfortified breast milk may increase nutrient accretion and growth rates and may improve neurodevelopmental outcomes.

OBJECTIVES

To determine whether multi-nutrient fortified human breast milk improves important outcomes (including growth and development) over unfortified breast milk for preterm infants without increasing the risk of adverse effects (such as feed intolerance and necrotising enterocolitis).

SEARCH METHODS

We used the standard search strategy of the Cochrane Neonatal Review Group. This included electronic searches of the Cochrane Central Register of Controlled Trials (CENTRAL; 2016, Issue 2), MEDLINE, EMBASE and the Cumulative Index to Nursing and Allied Health Literature (CINAHL) (until February 2016), as well as conference proceedings and previous reviews.

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials that compared feeding preterm infants with multi-nutrient (protein and energy plus minerals, vitamins or other nutrients) fortified human breast milk versus unfortified (no added protein or energy) breast milk.

DATA COLLECTION AND ANALYSIS

We extracted data using the standard methods of the Cochrane Neonatal Review Group. We separately evaluated trial quality, data extracted by two review authors and data synthesised using risk ratios (RRs), risk differences and mean differences (MDs). We assessed the quality of evidence at the outcome level using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

MAIN RESULTS

We identified 14 trials in which a total of 1071 infants participated. The trials were generally small and weak methodologically. Meta-analyses provided low-quality evidence that multi-nutrient fortification of breast milk increases in-hospital rates of growth (MD 1.81 g/kg/d, 95% confidence interval (CI) 1.23 to 2.40); length (MD 0.12 cm/wk, 95% CI 0.07 to 0.17); and head circumference (MD 0.08 cm/wk, 95% CI 0.04 to 0.12). Only very limited data are available for growth and developmental outcomes assessed beyond infancy, and these show no effects of fortification. The data did not indicate other potential benefits or harms and provided low-quality evidence that fortification does not increase the risk of necrotising enterocolitis in preterm infants (typical RR 1.57, 95% CI 0.76 to 3.23; 11 studies, 882 infants).

AUTHORS' CONCLUSIONS

Limited available data do not provide strong evidence that feeding preterm infants with multi-nutrient fortified breast milk compared with unfortified breast milk affects important outcomes, except that it leads to slightly increased in-hospital growth rates.

Gastric Emptying and Curding of Pasteurized Donor Human Milk and Mother's Own Milk in Preterm Infants

We evaluated the effects of fortification and composition on gastric emptying and curding in un/fortified pairs of mother's own milk (MOM, n = 17) and pasteurized donor human milk (PDHM, n = 15) in preterm infants. Retained meal proportions (%) and curding were determined from sonography. Immediate and subsequent postprandial % were higher for PDHM (23%, P = 0.026; 15%, P = 0.006) and fortified meals (31.5%; 8.8%, both P < 0.001), whereas higher casein, whey, and lactose concentrations were associated with lower immediate postprandial % (all P < 0.006). Curding did not affect emptying. Influences of fortification, pasteurization, and differing breast milk compositions are small and unlikely implicated in preterm feeding intolerance.

Influence of Food on Paediatric Gastrointestinal Drug Absorption Following Oral Administration: A Review

The objective of this paper was to review existing information regarding food effects on drug absorption within paediatric populations. Mechanisms that underpin food-drug interactions were examined to consider potential differences between adult and paediatric populations, to provide insights into how this may alter the pharmacokinetic profile in a child. Relevant literature was searched to retrieve information on food-drug interaction studies undertaken on: (i) paediatric oral drug formulations; and (ii) within paediatric populations. The applicability of existing methodology to predict food effects in adult populations was evaluated with respect to paediatric populations where clinical data was available. Several differences in physiology, anatomy and the composition of food consumed within a paediatric population are likely to lead to food-drug interactions that cannot be predicted based on adult studies. Existing methods to predict food effects cannot be directly extrapolated to allow predictions within paediatric populations. Development of systematic methods and guidelines is needed to address the general lack of information on examining food-drug interactions within paediatric populations.

Influences of breast milk composition on gastric emptying in preterm infants

OBJECTIVES

The aim of the present study was to determine whether specific biochemical and energy concentrations influence gastric emptying of unfortified and fortified mother's own milk (MOM) in stable preterm infants, and whether gastric emptying differs between feeds of unfortified MOM and feeds fortified with S-26 or FM 85 human milk fortifier (HMF) when infants are fed the same volume under similar conditions. Influences of infant gestation, age, and weight, and feed characteristics were also explored.

METHODS

Stomach volumes of 25 paired unfortified and fortified MOM feeds were monitored prefeed and postfeed delivery and at 30-minute intervals thereafter. For each feed, MOM samples were analyzed to determine concentrations of total protein, casein, whey, carbohydrate, lactose, fat, and energy. Fortified feed compositions were calculated by adding fortifier biochemical and energy concentrations to unfortified MOM concentrations. Ultrasound images were used to calculate infant stomach volumes. Statistical comparisons were made of paired stomach volume measurements.

RESULTS

Higher feed concentrations of casein were associated with faster gastric emptying during feed delivery (P = 0.007). When compared with unfortified MOM, S-26 fortified feeds emptied similarly, whereas FM 85 fortified feeds emptied more slowly both during feed delivery and during the postprandial period (P = 0.002, <0.001, respectively). Gastric emptying was slower for 2-hourly feeds compared with that for 3-hourly feeds (P = 0.003) and in supine position compared with that in prone (P = 0.001).

CONCLUSIONS

Breast milk composition influences gastric emptying in stable preterm infants, with feeds of higher casein concentration emptying faster during feeding than otherwise equivalent feeds, and FM 85 fortified MOM emptying more slowly than unfortified MOM.

Specificity of infant digestive conditions: some clues for developing relevant in vitro models

Digestion of nutrients is an essential function of the newborn infant gut to allow growth and development and understanding infant digestive function is essential to optimize nutrition and oral drug delivery. Ethical considerations prohibit invasive in vivo trials and as a consequence in vitro assays are often conducted. However, the choice of in vitro model parameters are not supported by an exhaustive analysis of the literature and do not mimic precisely the digestive conditions of the infant. This review contains a compilation of the studies which characterized the gastroduodenal conditions in full-term or preterm infants of variable postnatal age from birth up to six months. Important data about healthy full-term infants are reported. The enzymatic (type of enzymes and level of activity) and nonenzymatic (milk-based diet, frequency of feeding, bile salt concentrations) conditions of digestion in infants are shown to differ significantly from those in adults. In addition, the interindividual and developmental variability of the digestive conditions in infants is also highlighted.

Preterm dietary study: meal frequency, regurgitation and the surprisingly high use of laxatives among formula-fed infants following discharge

AIM

To describe eating habits and possible feeding intolerance among preterm infants based on type of nutrition.

METHODS

The parents of infants born below 32 weeks filled in questionnaires, before and after discharge, about type of nutrition, number of meals, regurgitation, number of stools and laxative use.

RESULTS

A total of 769 questionnaires based on 286 very preterm infants were completed, and 753 were included. At 40 weeks of corrected age, infants fed both fortified and unfortified human milk received more daily meals (mean 7.37 and 7.57) than preterm formula-fed infants (mean 6.79) (p < 0.05). Fortification of human milk did not seem to increase the incidence of regurgitation. Between 38.7 and 42.9% of the preterm infants were treated with laxatives from discharge to 6 months of corrected age. Infants fed preterm formula prior to discharge, at term, at 2 and 4 months of corrected age received laxatives more often than infants fed human milk, with odds ratios of 13.7, 137.5, 49.7 and 40.5, respectively (p ≤ 0.001).

CONCLUSION

Constipation seems to be frequent among very preterm infants. Laxative use averaged 40% across all the different feeding groups and was as high as 70-85% in formula-fed preterm infants over the course of the study.

Validation of ultrasound methods to monitor gastric volume changes in preterm infants

OBJECTIVES

The aim of this study was to validate 4 sonographic methods of estimating stomach volume for the purpose of monitoring changes in gastric volume over time and to describe the echogenic characteristics of milk feeds.

METHODS

Twenty-four infants were monitored during a single intragastric tube feed, with 2 ultrasound images of the entire stomach and an image of the antral cross-sectional area (ACSA) before, during, and after the feed. Raw measurements, 3 stomach volume calculations, and ACSA were tested for intra- and interrater agreement. Calculated stomach volumes and ACSA were compared with delivered feed volumes, and characteristics of stomach image echogenicity graded at each time point.

RESULTS

Spheroid calculation of stomach volume was the most reliable and valid measure of stomach volume. Fortified breast milk feeds were more echogenic than unfortified breast milk feeds. Residual stomach volumes (median 2.12 mL, range 0.59-9.27 mL) were identified in 18 of 24 infants.

CONCLUSIONS

Direct ultrasound stomach measurement (spheroid) will provide a useful research tool and a potential clinical tool for assessing gastric emptying and feeding intolerance in preterm infants.

Multinutrient fortification of human breast milk for preterm infants following hospital discharge

BACKGROUND

Preterm infants are usually growth restricted at hospital discharge. Feeding preterm infants after hospital discharge with multinutrient fortified breast milk rather than unfortified breast milk may facilitate more rapid catch-up growth and improve neurodevelopmental outcomes.

OBJECTIVES

To determine the effect of feeding preterm infants following hospital discharge with multinutrient fortified human breast milk versus unfortified breast milk on growth and development.

SEARCH METHODS

We used the standard search strategy of the Cochrane Neonatal Review Group. This included electronic searches of the Cochrane Central Register of Controlled Trials Register (CENTRAL, The Cochrane Library, 2012, Issue 3), MEDLINE, EMBASE and CINAHL (until August 2012), conference proceedings, and previous reviews.

SELECTION CRITERIA

Randomised or quasi-randomised controlled trials that compared feeding preterm infants following hospital discharge with multinutrient fortified breast milk compared with unfortified human breast milk.

DATA COLLECTION AND ANALYSIS

We extracted data using the standard methods of the Cochrane Neonatal Review Group with separate evaluation of trial quality and data extraction by two review authors and synthesis of data using risk ratio, risk difference and mean difference.

MAIN RESULTS

We identified two small trials involving a total of 246 infants. These did not provide evidence that multinutrient fortification of breast milk for three to four months after hospital discharge affected rates of growth during infancy. One trial assessed infants at 18 months corrected age and did not find any statistically significant effects on neurodevelopmental outcomes.

AUTHORS' CONCLUSIONS

The limited available data do not provide convincing evidence that feeding preterm infants with multinutrient fortified breast milk compared with unfortified breast milk following hospital discharge affects important outcomes including growth rates during infancy. There are no data on long-term growth. Since fortifying breast milk for infants fed directly from the breast is logistically difficult and has the potential to interfere with breast feeding, it is important to determine if mothers would support further trials of this intervention.

Multinutrient fortification of human breast milk for preterm infants following hospital discharge

BACKGROUND

Preterm infants are usually growth restricted at hospital discharge. Feeding preterm infants after hospital discharge with multinutrient fortified breast milk rather than unfortified breast milk may facilitate more rapid catch-up growth and improve neurodevelopmental outcomes.

OBJECTIVES

To determine the effect of feeding with multinutrient fortified human breast milk versus unfortified breast milk on growth and development in preterm or low birth weight infants following hospital discharge.

SEARCH STRATEGY

The standard search strategy of the Cochrane Neonatal Review Group was used. This included searches of the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 4, 2010), MEDLINE (1966 to April 2010), EMBASE (1980 to April 2010), CINAHL (1982 to April 2010), conference proceedings, and previous reviews.

SELECTION CRITERIA

Randomised or quasi-randomised controlled trials that compared feeding preterm infants following hospital discharge with multinutrient fortified breast milk compared with unfortified human breast milk.

DATA COLLECTION AND ANALYSIS

The standard methods of the Cochrane Neonatal Review Group were used, with separate evaluation of trial quality and data extraction by two review authors.

MAIN RESULTS

One small trial (N = 39) was identified. Multinutrient fortification of breast milk for 12 weeks after hospital discharge resulted in higher rates of growth during infancy. At 12 months corrected age, weight (mean difference 1187g, 95% confidence interval (CI) 259, 2115 g), length (3.8 cm, 95%CI 1.2, 6.4 cm) and head circumference (1.0 cm, 95%CI 0.1, 1.9 cm) were statistically significantly greater in the intervention group. No evidence of an effect on neurodevelopmental assessments at 18 months corrected age was found.

AUTHORS' CONCLUSIONS

The limited available data suggest that feeding preterm infants following hospital discharge with multinutrient fortified breast milk compared with unfortified breast milk increases growth rates during infancy. The importance of these effects on long-term growth and development is unclear and deserves further assessment in randomised controlled trials. Since fortifying breast milk for infants fed directly from the breast is logistically difficult and has the potential to interfere with breast feeding, it is important to determine if mothers would support further trials of this intervention.

Protein content and fortification of human milk influence gastroesophageal reflux in preterm infants

OBJECTIVES

: Preterm human milk (HM) may provide insufficient energy and nutrients and thus may need to be fortified. Our aim was to determine whether fat content, protein content, and osmolality of HM before and after fortification may affect gastroesophageal reflux (GER) in symptomatic preterm infants.

METHODS

: Gastroesophageal reflux was evaluated in 17 symptomatic preterm newborns fed naïve and fortified HM by combined pH/intraluminal-impedance monitoring (pH-MII). Human milk fat and protein content was analysed by a near-infrared reflectance analysis. Human milk osmolality was tested before and after fortification. Gastroesophageal reflux indexes measured before and after fortification were compared and were also related to HM fat and protein content and osmolality before and after fortification.

RESULTS

: An inverse correlation was found between naïve HM protein content and acid reflux index (RIpH: P = 0.041, rho =-0.501). After fortification, osmolality often exceeded the values recommended for infant feeds; furthermore, a statistically significant (P < 0.05) increase in nonacid reflux indexes was observed.

CONCLUSIONS

: Protein content of naïve HM may influence acid GER in preterm infants. A standard fortification of HM may worsen nonacid GER indexes and, due to the extreme variability in HM composition, may overcome both recommended protein intake and HM osmolality. Thus, an individualised fortification, based on the analysis of the composition of naïve HM, could optimise both nutrient intake and feeding tolerance.

Human milk fortifiers in very low birth weight infants

The use of HMF remains an important option and has become common practice in all neonatal intensive care units. However, optimal composition of fortifiers is still undefined and more data are needed on safety and long-term benefits. Further research should be directed toward comparisons between different proprietary preparations, evaluating both short-term and long-term outcomes and adverse effects, in search of the best method of fortification.

Human milk fortification and gastric emptying in the preterm neonate

Fortification of expressed breast milk (EBM) is widely recommended for preterm feeding. Fortification of EBM results in increased caloric density and osmolarity, both of which may retard gastric emptying. As gastric emptying is a major determinant of feed tolerance, we investigated the effect of fortification (with Lactodex HMF) of EBM on gastric emptying in preterm neonates. The half gastric emptying time was measured using real time ultrasonography in 25 consecutive preterm neonates first on EBM alone, then on EBM + Lactodex HMF. Each baby served as its own control. The students t-test was used for statistical analysis. The mean gestation age was 34.48 +/- 0.77 weeks. The mean birth weight was 1.92 +/- 0.14 kg. The mean half gastric emptying time at an age of 5.4 +/- 0.86 days on EBM was 24.00 +/- 5.00 min and 24.40 +/- 5.06 min on EBM + human milk fortifier (HMF). The same at 2nd assessment (15.2 +/- 1.79 days), with EBM was 22.80 +/- 4.58 min vs. 23.60 +/- 4.89 min when given EBM + HMF. These differences were not statistically significant. Fortification of EBM with Lactodex HMF does not affect the gastric emptying in preterm neonates and therefore is unlikely to affect feed tolerance in them.

Multicomponent fortification of human breast milk for preterm infants following hospital discharge

BACKGROUND

Preterm infants are usually growth restricted at hospital discharge. Feeding preterm infants after hospital discharge with nutrient-fortified breast milk (rather than unfortified breast milk) may facilitate more rapid catch-up growth and improve neurodevelopmental outcomes.

OBJECTIVES

To determine the effect of feeding with multicomponent fortified human breast milk versus unfortified breast milk on growth and development on preterm or low birth weight infants following hospital discharge.

SEARCH STRATEGY

The standard search strategy of the Cochrane Neonatal Review Group was used. This included searches of the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 2, 2007), MEDLINE (1966 - May 2007), EMBASE (1980 - May 2007), CINAHL (1982 - May 2007), conference proceedings, and previous reviews.

SELECTION CRITERIA

Randomised or quasi-randomised controlled trials that compared feeding preterm infants following hospital discharge with multicomponent fortified breast milk compared with unfortified human breast milk.

DATA COLLECTION AND ANALYSIS

The standard methods of the Cochrane Neonatal Review Group were used, with separate evaluation of trial quality and data extraction by two review authors.

MAIN RESULTS

No eligible trials were identified.

AUTHORS' CONCLUSIONS

There are no data from randomised controlled trials to determine whether feeding preterm infants following hospital discharge with multicomponent-fortified breast milk compared with unfortified breast milk affects growth and development. Given the potential for nutrient fortification to affect growth and development, this intervention may merit further assessment. Since fortifying breast milk for infants fed directly from the breast is logistically difficult (and has the potential to interfere with breast-feeding), it would be important to determine if mothers would support a trial of this intervention. It may be that a trial should first focus on infants who are not able to consume ad libitum quantities of breast milk directly from the breast, who have poor growth or nutritional status, or who have on-going additional metabolic requirements.

Effect of Erythromycin on Gastric Emptying Time of Low Birth Weight Babies

BACKGROUND

To study the promotility effects of low dose erythromycin on gastric emptying time in a population of normal low birth weight (LBW) neonates on breast feeds with or without nutritional supplements and human milk fortifier (HMF).

METHOD

A randomised control trial involving 50 neonates was undertaken and they were given 6mg/kg/day of oral erythromycin or placebo in three divided doses for four consecutive days in the first two weeks of life. The gastric emptying time (GET) was assessed ultrasonographically by measuring the decrease in the antral cross sectional area (ACSA). The time taken for the ACSA to become half the prefeed value, was taken as t/2 or half GET. The babies were also assessed for pre and post intervention side effects of the drug. The results were analysed using SPSS ver 11.5.

RESULTS

The test group showed a significant decrease in GET after the intervention. This effect was mainly seen in the preterm babies as compared to term Small for Gestational Age (SGA) babies. The decrease in GET was more in babies born after 34 weeks of gestation as compared to smaller babies. The reduction in GET was seen in babies on breast milk alone and nutritional supplements with breast milk but not when HMF was added. No side effects of the drug were noted.

CONCLUSION

Low dose erythromycin is a safe way of decreasing gastric emptying in preterm babies born after 34 weeks of gestation in the first two weeks of life.

Modern fasting guidelines in children

Pediatric fasting guidelines are intended to reduce the risk of pulmonary aspiration of gastric contents and facilitate the safe and efficient conduct of anesthesia. Recent changes in these guidelines, while assuring appropriate levels of patient safety, have been directed at improving the overall perioperative experience for infants, children, and their parents. Now after nearly 15 years of practice worldwide, the relative safety and benefits of allowing clear liquids up to 2 hr prior to anesthesia for otherwise healthy children are well established. Shortened fasting periods for breast milk (3 hr), formula (4 hr) and light meals (6 hr) are supported by accumulated experience and an evolving literature that includes evidence of minimal gastric fluid volumes (GFVs) at the time of surgery. Ideal fasting intervals for children with disorders that may affect gastrointestinal transit have yet to be determined.

Strategies for prevention of feed intolerance in preterm neonates: a systematic review

Postnatal growth restriction and failure to thrive have been recently identified as a major issue in preterm, especially extremely-low-birth-weight neonates. An increased length of time to reach full enteral feedings is also significantly associated with a poorer mental outcome in preterm neonates at 24 months corrected age. Optimization of enteral nutrition without increasing the risk of necrotizing enterocolitis (NEC) has thus become a priority in preterm neonates. A range of feeding strategies currently exists for preventing/minimizing feed intolerance in preterm neonates reflecting the dilemma surrounding the definition and significance of signs of feed intolerance due to ileus of prematurity and the fear of NEC. The results of a systematic review of current strategies for preventing/minimizing feed intolerance in preterm neonates are discussed. The need for clinical research in the area of signs of feed intolerance is emphasized to develop a scientific basis to feeding strategies. Only large pragmatic trials based on such strategies will reveal whether the benefits (improved growth and long term neurodevelopmental outcomes) of aggressive enteral nutrition can outweigh the risks of a potentially devastating illness like NEC, and of prolonged parenteral nutrition in preterm neonates.

Gastric emptying in premature newborns with acute respiratory distress

OBJECTIVES

The authors hypothesized that acute respiratory distress (ARD) delays gastric emptying. The objective was to test this hypothesis by assessing gastric emptying on the second and seventh days of life in premature infants with ARD resulting from pulmonary disease.

METHODS

Thirty-nine newborns with ARD starting on the first day of life were selected and paired with 39 healthy control newborns matched by weight (within 250 g). Gestational age was <or =35 weeks and birth weight was < or =1750 g for all subjects. Gastric emptying was assessed at 48.0 +/- 24.0 hours and at 168.0 +/- 24.0 hours of life. A test meal consisting of 3 mL/kg of 5% glucose in water labeled with phenol red was administered by gastric tube over 1 minute and gastric retention was determined as percent test meal remaining in the stomach 30 minutes after administration.

RESULTS

Gastric retention at 30 minutes varied considerably in both groups and was significantly higher (P < 0.01) in newborns with ARD (61.4%) than controls (51.8%) at 48.0 +/- 24.0 hours, decreasing significantly after partial or full remission of ARD at 168 +/- 24 hours of life. Gastric retention was 60.2% in newborns with feeding intolerance and 36.8% in tolerant newborns (P < 0.001) at 168 hours. ARD and periventricular or intraventricular hemorrhage were predictors of gastric retention at 48 +/- 24 hours of life, whereas feeding intolerance and gestational age were predictors of gastric retention at 168 +/- 24 hours. Gastric retention was inversely correlated with gestational age.

CONCLUSION

Gastric emptying is delayed in premature infants with ARD during the first 72 hours of life and may impair the initiation of enteral feeding.

Multicomponent fortified human milk for promoting growth in preterm infants

BACKGROUND

For term infants, human milk provides adequate nutrition to facilitate growth, as well as potential beneficial effects on immunity and the maternal-infant emotional state. However, the role of human milk in premature infants is less well defined as it contains insufficient quantities of some nutrients to meet the estimated needs of the infant. Observational studies have suggested that infants fed formula have a higher rate of growth than infants who are breast fed. However, there are potential short term and long term benefits from human milk. Commercially-produced multicomponent fortifiers provide additional nutrients to supplement human milk (in the form of protein, calcium, phosphate, and carbohydrate, as well as vitamins and trace minerals).

OBJECTIVES

The main objective was to determine if addition of multicomponent nutritional supplements to human milk leads to improved growth, bone metabolism and neurodevelopmental outcomes without significant adverse effects in premature infants.

SEARCH STRATEGY

Searches were made of the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 2, 3003), MEDLINE (searched August 29, 2003), previous reviews including cross references, abstracts, conferences and symposia proceedings, expert informants, journal handsearching mainly in the English language.

SELECTION CRITERIA

All trials utilising random or quasi-random allocation to supplementation of human milk with multiple nutrients or no supplementation in premature infants within a nursery setting were eligible.

DATA COLLECTION AND ANALYSIS

Data were extracted using the standard methods of the Cochrane Collaboration and its Neonatal Review Group, with separate evaluation of trial quality and data extraction by each author and synthesis of data using relative risk and weighted mean difference.

MAIN RESULTS

Supplementation of human milk with multicomponent fortifiers is associated with short term increases in weight gain, linear and head growth. There is no effect on serum alkaline phosphatase levels; it is not clear if there is an effect on bone mineral content. Nitrogen retention and blood urea levels appear to be increased. There are insufficient data to evaluate long term neurodevelopmental and growth outcomes, although there appears to be no effect on growth beyond one year of life. Use of multicomponent fortifiers does not appear to be associated with adverse effects, although the total number of infants studied and the large amount of missing data reduces confidence in this conclusion. Blood urea levels are increased and blood pH levels minimally decreased, but the clinical significance of this is uncertain.

REVIEWER'S CONCLUSIONS

Multicomponent fortification of human milk is associated with short-term improvements in weight gain, linear and head growth. Despite the absence of evidence of long-term benefit and insufficient evidence to be reassured that there are no deleterious effects, it is unlikely that further studies evaluating fortification of human milk versus no supplementation will be performed. Further research should be directed toward comparisons between different proprietary preparations and evaluating both short-term and long-term outcomes in search of the "optimal" composition of fortifiers.

Ultrasonography and gastric emptying in children: validation of a sonographic method and determination of physiological and pathological patterns

BACKGROUND

The association between gastric emptying and gastro-esophageal reflux (GER) has been widely recognised from scintigraphic studies.

OBJECTIVE

A prospective study to (a) validate US as a means of measuring gastric emptying, (b) determine physiological patterns of gastric emptying and (c) measure gastric emptying in symptomatic refluxers.

MATERIALS AND METHODS

Three cohorts were studied: (a) Ten babies in whom gastric emptying was measured by US and scintigraphy; (b) gastric emptying in 330 asymptomatic children aged between 15 days and 10 years to determine physiological variations; and (c) gastric emptying in 552 children with GER, manifesting as vomiting or cardiorespiratory problems.

RESULTS

US and scintigraphic techniques showed general concordance in 90% of cases. In the remaining 10%, discordant results were related to overlapping of duodenum and stomach during scintigraphy and shadowing of the gastric antrum by air during US. Tremendous variations were induced by change of feed volume or type of formula, underlining the need for a standardised procedure. Twenty-two percent of cases showed a peculiar 'plateau' which differed significantly from the physiological patterns. Most of these babies had esophagitis or acute life-threatening events.

CONCLUSIONS

Investigation of gastric emptying seems to be a key element in the assessment of children with 'pathological' GER. US is a safe and cheap alternative to scintigraphy for the assessment of gastric emptying.

Breastfeeding: making the difference in the development, health and nutrition of term and preterm newborns

Breastfeeding is the natural and safe way of feeding small infants, providing nutritional, immunological, psychological and economic recognized and unquestionable advantages. These qualities are especially important in premature infants, because of their vulnerability. Despite highly desirable, there is, in general, little success in breastfeeding preterm infants, especially in special care neonatal units. There are evidences that a high supportive hospital environment, with an interdisciplinary team, makes possible to these infants to be breastfed. In this article, the authors present an up-to-date review about the components of human milk and its unique characteristics, as well as describes aspects that make the breast milk particularly suitable for feeding the premature newborn.

Maternal lactation for preterm newborn infants

In recent decades, neonatologists have made considerable progress in life support techniques, especially in the treatment and prevention of respiratory disorders, which has led to a higher neonatal survival rate. Research into neonatal nutrition has also produced great benefits. It has been found that one of the key points regarding the improved survival rate of infants is the necessity for nutrition that is both adequate and as natural as possible. In this respect, it is necessary to achieve a better understanding of the process, protection, support and maintenance of maternal lactation in neonatal units. Humanization of perinatal attention during delivery, respect for the rights of parents and their children, protection of the mother and child bonding process, early skin contact with the mother and greater attention to individualized care are all key factors in the reinforcement of maternal lactation and are issues that must be addressed within the field of neonatology. Research activities need to concern themselves with: (1) acquiring greater knowledge concerning the common problems and difficulties that arise with mothers and their preterm babies; (2) training healthcare professionals in these aspects, for example in the extraction and storage of milk and in improving techniques of emotional and communicational skills; (3) by means of specific programmes such as the setting up of support groups, so that the effort made to encourage the initiation of breastfeeding is justified by its continuation for as long as possible. Thus, we hope to establish standards of care based on starting, encouraging and prolonging maternal lactation, in sufficient quantity and quality, always remembering that the fundamental goal of our research is the well-being of the child and its family.

Early aggressive nutrition in preterm infants

Increasingly, neonatologists are realizing that current feeding practices for preterm infants are insufficient to produce reasonable rates of growth, and earlier and larger quantities of both parenteral and enteral feeding should be provided to these infants. Unfortunately, there is very little outcome data to recommend any particular nutritional strategy to achieve better growth. Instead, the rationale for feeding regimens in many nurseries has been quite variably extrapolated from animal data and human studies conducted in gestationally more mature and/or stable neonates. Additionally, there are no well-controlled, prospective studies that validate any nutritional regimen for the very preterm and or sick, unstable neonate. The goal of this review is to present available data to help define the risks and benefits of early parenteral and enteral nutrition, particularly in very preterm neonates, concluding with a more aggressive approach to feeding these infants than has been customary practice.

Gastroesophageal reflux and aspiration of gastric contents in anesthetic practice

General anesthesia may predispose patients to aspiration of gastroesophageal contents because of depression of protective reflexes during loss of consciousness. In addition, some patients may be at increased risk of pulmonary aspiration because of retention of gastric contents caused by pain, inadequate starvation, or gastrointestinal pathology resulting in reduced gastric emptying and gastroesophageal reflux. Despite increasing knowledge of the problems associated with aspiration, the relatively small incidence and associated mortality rates in the perioperative period do not appear to have changed markedly over the last few decades. In this review article, the physiological factors associated with an increased risk of gastroesophageal reflux and aspiration are considered together with some of the methods that are used to prevent aspiration. In particular, preoperative starvation, the use of drugs designed to increase gastric pH, recent developments in airway devices, and appropriate application of cricoid pressure are critically appraised.

The use of human milk for premature infants

Various methods have been reported and used clinically to augment the nutrient supply for human milk-fed premature infants. These methods include specialized maltinutrient powdered mixtures (fortifiers), complete liquid formulas designed to be mixed with human milk, complete powdered formulas to be mixed with human milk, and alternate feeding of human milk and preterm formula. Although the optimum nutrition of premature infants is unknown, data are accumulating to suggest that human milk, fortified with additional nutrients, is appropriate for tube-fed infants. The use of fortified human milk typically provides premature infants adequate growth, nutrient retention, and biochemical indices of nutritional status when fed at approximately 180 mL/kg/d compared with unfortified human milk. Data are needed to determine the precise quantity of nutrients to be added as supplements. Nutrient interactions have not been explored in detail. Although large quantities of calcium seem to be needed, the exogenous calcium may affect fat absorption adversely. Manipulation of milk may affect the intrinsic host-defense properties of the milk. Compared with preterm formula, the feeding of fortified human milk may provide significant protection from infection and NEC. Lastly, the potential stimulation of an enteromammary pathway through skin-to-skin contact provides species-specific antimicrobial protection for premature infants. Several of these areas require additional exploration. Thus, for premature infants, neonatal centers should encourage the feeding of fortified human milk, together with skin-to-skin contact, as reasonable methods to enhance milk production while potentially facilitating the development of an enteromammary response.

Enteral feeding of the micropremie

Clinical practice demands knowledge of gastrointestinal ontogeny and the factors that affect our ability to use enteral feeding in the micropremie. The decisions regarding milk type (when and how it should be given) are considered in the light of current physiologic and clinical evidence. Special considerations apply in the micropremie who is also small for gestational age and NEC must be avoided. Trophic feeding now has an established role, allowing the infant to benefit from enteral feeds even when full nutritive milk feeding is not possible.

Multicomponent fortified human milk for promoting growth in preterm infants

BACKGROUND

For term infants, human milk provides adequate nutrition to facilitate growth, as well as potential beneficial effects on immunity and the maternal-infant emotional state. However, the role of human milk in premature infants is less well defined as it contains insufficient quantities of some nutrients to meet the estimated needs of the infant. There are potential short term and long term benefits from human milk, although observational studies have suggested that infants fed formula have a higher rate of growth than infants who are breast fed. Commercially-produced multicomponent fortifiers provide additional nutrients to human milk (in the form of protein, calcium, phosphate, and carbohydrate, as well as vitamins and trace minerals).

OBJECTIVES

The main objective was to determine if addition of multiple dietary supplements to human milk leads to improved growth, bone metabolism and neurodevelopmental outcomes without significant adverse effects in premature infants.

SEARCH STRATEGY

The standard search strategy of the Neonatal Review Group was used. This includes searches of the Oxford Database of Perinatal Trials, MEDLINE, previous reviews including cross references, abstracts, conferences and symposia proceedings, expert informants, journal handsearching mainly in the English language.

SELECTION CRITERIA

All trials utilising random or quasi-random allocation to supplementation of human milk with multiple nutrients or no supplementation in premature infants within a nursery setting were eligible.

DATA COLLECTION AND ANALYSIS

Data were extracted using the standard methods of the Cochrane Collaboration and its Neonatal Review Group, with separate evaluation of trial quality and data extraction by each author and synthesis of data using relative risk and weighted mean difference.

MAIN RESULTS

Supplementation of human milk with multicomponent fortifiers is associated with short term increases in weight gain, linear and head growth. There is no effect on serum alkaline phosphatase levels. Bone mineral content and nitrogen retention appear to be increased. There are insufficient data to evaluate long term neurodevelopmental and growth outcomes. Adverse effects of fortification do not appear to be significantly increased, although the total number of infants studied and the unavailability of results for some infants randomized and subsequently withdrawn reduces confidence in this conclusion. Blood urea levels are increased and blood pH levels minimally decreased, but the significance of this is uncertain.

REVIEWER'S CONCLUSIONS

Multicomponent fortification of human milk is associated with short-term improvements in weight gain, linear and head growth. Despite the absence of evidence of long-term benefit and insufficient evidence to be reassured that there are no deleterious effects, it is unlikely that further studies evaluating fortification of human milk versus no supplementation will be performed. Further research should be directed toward comparisons between different proprietary preparations and evaluating both short-term and long-term outcomes in search of the "optimal" composition of fortifiers.

Enteral feeding in the preterm infant

In planning enteral feeding in the preterm infant, decisions need to be made regarding the feeding schedule, choice of milk, and the route of administration. Feeds should be commenced within a week after birth beginning with subnutritional quantities. Preterm human milk from the infant's own mother is the milk of choice. When full enteral feeding is established, supplementation with human milk fortifier is recommended. Donor human milk and preterm formula are alternatives. Early establishment of enteral nutrition and maintenance of optimal nutrition during infancy are important as dietary manipulations in preterm infants have potential long-term influences on their health, growth and neurodevelopment.

Effects of nutrients in human milk on the recipient premature infant

As the rate of survival of premature infants is increasing, more attention is necessarily focused on improving the quality of survival through optimal nutritional management. The nutritional needs of the premature infant are greater than at any other time in the life cycle. The benefits of human milk for term infants are well known. Emerging data suggest that human milk may especially benefit the premature infant. The human milk-fed premature infant may experience improved health (such as lower rates of infection and necrotizing enterocolitis), gastrointestinal function, and neurodevelopment. These factors may outweigh the concerns about adequate growth, nutrient accretion, and biochemical indices of nutritional status attributed to the lower nutrient content of human milk compared with preterm formula. Some of the nutritional concerns may be met by the use of multinutrient supplements during the time infants receive tube-feeding, generally the time prior to attaining complete oral feeding in-hospital. The available data suggest that the quality of survival of premature infants can be improved, both in the short-term and long-term, through the feeding of human milk.

Randomised controlled trial of cisapride in preterm infants

AIM

To determine the effect of cisapride on gastrointestinal motility in preterm infants.

METHODS

Cisapride (0.2 mg/kg, 8 hourly ) or placebo was given first for seven days in a double blind randomised crossover study of 10 preterm infants. Gastrointestinal motility was assessed on day 3 of each treatment. The half gastric emptying time (GET1/2) was determined by using ultrasonography to measure the decrease in the gastric antral cross sectional area after a feed. The whole gastrointestinal transit time (WGTT) was assessed by timing the transit of carmine red through the gut. Treatments were compared using the Wilcoxon matched pairs signed ranks test.

RESULTS

Median (range) birthweight was 1200 (620, 1450) g and postconceptional age 33 (29, 34) weeks at recruitment. GET1/2 was significantly longer during cisapride treatment than during placebo; the median of the differences (95% confidence interval) was 19.2 (11, 30 minutes, p=0.008). WGTT was also longer during cisapride treatment, but the difference was not significant; the median of the differences was 11(-18, 52 hours, p=0.1).

CONCLUSIONS

Cisapride delays gastric emptying and may delay WGTT in preterm infants. Its use to promote gastrointestinal motility in this group cannot be recommended.

Randomised controlled trial of trophic feeding and gut motility

OBJECTIVES

To determine the effect of trophic feeding on gastric emptying and whole gut transit time in sick preterm infants.

METHODS

A randomised, controlled, prospective study of 70 infants weighing less than 1750 g at birth, who were receiving ventilatory support, was performed. Group TF (33 infants) received trophic feeding from day 3 (0.5 ml/h if birthweight less than 1 kg, 1 ml/h if greater or equal to 1 kg) in addition to parenteral nutrition until ventilatory support finished. Group C (37 infants) received parenteral nutrition alone until ventilatory support finished. Expressed breast milk or a preterm formula were given according to maternal preference. Gastric emptying was assessed within 24 hours of nutritive milk feeding equal to 90 ml/kg/day, using ultrasound scans to measure the reduction in the gastric antral cross sectional area after a feed. Whole gut motility was assessed at both 3 and 6 weeks of age by measuring the whole gut transit time (WGTT) of the marker carmine red.

RESULTS

There was no significant difference between groups in their gastric half emptying time, median difference (95% confidence interval) 2.6 (-5.9, 13.9) minutes. The WGTT was significantly faster (p < 0.05) in group TF at both 3 and 6 weeks; median difference -13 (-47, -0.1) and -12.5 (-44, -0.5) hours, respectively.

CONCLUSIONS

Trophic feeding enhances whole gut motility but not gastric emptying. This effect could subsequently improve milk tolerance in sick preterm infants.

Effect of feed interval and feed type on splanchnic haemodynamics

AIM

To study the effect of enteral feeding on splanchnic blood flow velocity in preterm infants.

METHOD

Coeliac axis and superior mesenteric artery (SMA) blood flow velocity were measured longitudinally in a cohort of 61 babies using Doppler ultrasound.

RESULTS

Babies fed 1 hourly had significantly higher preprandial SMA peak systolic velocity (PSV) than those fed 3 hourly (70 vs 53 cm/s). Those fed 1 hourly showed no postprandial change whereas those fed 3 hourly showed significant postprandial hyperaemia. This hyperaemia had longer latency (42 vs 27 mins) and smaller amplitude (31 vs 25 mins) after expressed breast milk compared with preterm formula. The addition of long chain polyunsaturated fatty acids to the formulas had no effect on the postprandial response.

CONCLUSION

Hourly bolus feeding leads to a persistent hyperaemic state in the SMA. The composition of feeds is an important determinant of the postprandial response of the SMA to 3 hourly feeding.