Diet Management in Congenital Diarrheas and Enteropathies - General Concepts and Disease-Specific Approach, a Narrative Review.

Congenital diarrheas and enteropathies (CODE) are a group of rare, heterogenous, monogenic disorders that lead to chronic diarrhea in infancy. Definitive treatment is rarely available, and supportive treatment is the mainstay. Nutritional management in the form of either specialized formulas, restrictive diet, or parenteral nutrition support in CODE with poor enteral tolerance, is the cornerstone of CODE treatment and long-term growth. The evidence to support the use of specific diet regimens and nutritional approaches in most CODE disorders is limited due to the rarity of those diseases and the scant published clinical experience. The goal of this review is to create a comprehensive guide for nutritional management in CODE, based on the currently available literature, disease mechanism and the PediCODE group experience. Enteral diet management in CODE can be divided into 3 distinct conceptual frameworks - nutrient elimination, nutrient supplementation, and generalized nutrient restriction. Response to nutrient elimination or supplementation can lead to resolution or significant improvement in the chronic diarrhea of CODE and resumption of normal growth. This pattern can be seen in CODE due to carbohydrate malabsorption, defects in fat absorption and occasionally in electrolyte transport defects. In contrast, general diet restriction is mainly supportive. However, occasionally it allows parenteral nutrition weaning or reduction overtime mainly in enteroendocrine defects and rarely in epithelial trafficking and polarity defects. Further research is required to better elucidate the role of diet in the treatment of CODE and the appropriate diet management for each disease.

Dietary lysine requirements of older adults stratified by age and sex.

BACKGROUND: Current recommendation for lysine in older adults, 30 mg. kg-1.d-1, is based on young adult data. Evidence suggests that amino acid requirements may differ between young and old adults with both sex and age having an effect in the elderly OBJECTIVES: 1) Define the lysine requirements in healthy older adults using the indicator amino acid oxidation (IAAO) method with L-[1-13C]phenylalanine as the indicator and 2) compare the derived estimates based on age: 60-69y and >70y METHODS: Fourteen healthy males and 16 healthy females (> 60y, BMI=26.3 kg.m-2) were randomly assigned to receive 3 to 7 lysine intakes from 10 to 80 mg. kg-1. d-1. Subjects were adapted to a standard liquid diet providing 1.0 g. kg-1.d-1 protein and adequate energy, for 2 days, with indicator oxidation measurements performed on day three. The rate of release of 13CO2 from the oxidation of L-[1-13C] phenylalanine was measured in breath. A two-phase linear mixed effect model, and parametric bootstrap were used to determine mean lysine requirements and the 95% confidence intervals (CI). The overlap of the 95% CI between the 2 age groups were used to compare the requirement estimates. The null hypothesis was accepted if the interval contained zero RESULTS: The mean and upper 95% CI of the lysine requirement for females were 32.9 and 40.9, and 46.2 and 53.7 mg. kg-1.d-1 for those 60-69 and >70y, respectively. The mean and upper 95% CI of the lysine requirement for the 2 groups of males were not different, so was combined to yield a mean and 95% CI of 32.2 and 38.2 mg. kg-1.d-1 CONCLUSIONS: This is the first study to report on the lysine requirement in older adults >60y. These results provide a basis from which the adequacy of diets to meet lysine needs of older adults can be assessed. THE TRIAL WAS REGISTERED AT CLINICAL TRIALS REGISTRY: # NCT02008955, https://clinicaltrials.gov/study/NCT02008955.

Protein intake affects erythrocyte glutathione synthesis in healthy adults aged ≥60 years in a repeated-measures trial.

BACKGROUND: Protein recommendations for older adults are based on nitrogen balance data from young adults. Physiological studies using the indicator amino acid oxidation method suggest they need 30% to 50% more protein than current recommendations. We herein present glutathione (GSH) as a physiological estimate of protein adequacy in older adults. OBJECTIVES: The objective was to measure GSH kinetics in response to varying protein intakes in a repeated-measures design in healthy adults aged ≥60 y using the precursor-product method. METHODS: Sixteen healthy older adults (n = 8 male and n = 8 female; body mass index ≤30 kg/m2) were studied. Each received 4 of 6 protein intakes in random order (0.66, 0.8, 0.9, 1.1, 1.3 and 1.5 g⋅kg-1⋅d-1). At each intake level, participants underwent isotope infusion studies of 7 h duration following a 3-d adaptation to the test level of protein. On the fourth day, GSH fractional (FSR) and absolute synthesis (ASR) rates were quantified by measuring the incorporation of U-[13C2-15N]glycine into GSH at isotopic steady state. A mixed-effect change-point regression model was used to determine a breakpoint in FSR and ASR. Secondary outcomes included plasma concentrations of oxidative stress markers, homocysteine, 5-L-oxoproline (5-OP), and urinary sulfate. The effect of secondary outcomes on GSH kinetics was analyzed using a joint linear mixed-effect model and Tukey's post hoc test. RESULTS: A protein intake of 1.08 g⋅kg-1⋅d-1 (95% confidence interval [CI]: 0.83, 1.32; Rm2 = 0.207; Rc2 = 0.671; P < 0.001) maximized GSH FSR. There was no effect of protein intake on concentrations of erythrocyte GSH, plasma homocysteine, oxidative stress markers, or 5-OP (P > 0.05). Protein intake had a positive effect on urinary sulfate excretion (P < 0.0001). CONCLUSION: A protein intake of 1.08 g⋅kg-1⋅d-1 from a high-quality protein maximized GSH synthesis in adults ≥60 y. This lends support to data suggesting a requirement higher than the current recommendation. This study was registered at clinicaltrials.gov as NCT02971046.

Protein intake affects erythrocyte glutathione synthesis in young healthy adults in a repeated-measures trial.

BACKGROUND: In 2005, the Institute of Medicine advised using methods other than nitrogen balance (NB) for determining protein requirements. Since then, protein requirements using indicator amino acid oxidation (IAAO) have been published and are higher than NB. Glutathione (GSH), a tripeptide of cysteine, glutamate, and glycine, is a principal antioxidant that can be used as a functional indicator of protein adequacy. OBJECTIVES: The aim of this study was to measure changes in erythrocyte GSH kinetics [fractional synthesis rate (FSR) and absolute synthesis rate (ASR)] in healthy adults following a range of protein intakes at and above the current recommendations. METHODS: Sixteen healthy adults [8 males and 8 females, aged 25.6 ± 0.9 y (mean ± SEM)] were studied at 4 of 6 protein intakes ranging from 0.6 to 1.5 g⋅kg-1⋅d-1. Erythrocyte GSH kinetics were assessed during a 7-h infusion of [U-13C2-15N]glycine following 2 d of adaptation to each protein intake. Blood and urine tests were performed to measure oxidative stress markers, plasma homocysteine, triglycerides, plasma amino acid concentrations, 5-L-oxoproline (5-OP), and urinary sulfate. The protein intake that maximized GSH synthesis was determined using mixed-effect change-point regression in R. Primary and secondary outcomes were analyzed using linear mixed-effects and repeated-measures analysis of variance with Tukey's post hoc test. RESULTS: The protein intake that maximized GSH FSR at 78%⋅d-1 was 1.0 g⋅kg-1⋅d-1 (95% confidence interval: 0.63, 1.39). GSH ASR was significantly lower at 0.6 and 0.8 g⋅kg-1⋅d-1 than at 1.5 g⋅kg-1⋅d-1 (2.03 and 2.17, respectively, compared with 3.71 mmol⋅L-1⋅d-1). Increasing the protein intake led to increased urinary sulfate but did not affect erythrocyte GSH concentration, plasma oxidative stress markers, triglycerides, homocysteine, or 5-OP. CONCLUSIONS: A protein intake of 1.0 g⋅kg-1⋅d-1 maximized GSH synthesis, which is in agreement with earlier IAAO-derived protein requirements of 0.93 to 1.2 g⋅kg-1⋅d-1. These findings suggest that recommendations based on NB (0.66 g⋅kg-1⋅d-1) may underestimate protein needs for adequate health. This trial was registered at clinicaltrials.gov as NCT02971046.

The Minimum Methionine Requirement for Adults Aged ≥60 Years Is the Same in Males and Females.

The minimum methionine requirement in the presence of excess dietary cysteine has not been determined in older adults. This study aimed to determine the minimum methionine requirement in healthy older adults using the indicator amino acid oxidation (IAAO) method. Fifteen healthy adults ≥ 60 years of age received seven methionine intakes (0 to 20 mg/kg/d) plus excess dietary cysteine (40 mg/kg/d). Oxidation of the indicator, L-[1-13C]phenylalanine (F13CO2), was used to estimate the mean minimum methionine requirement using a change-point mixed-effect model. There was no statistical difference between male and female requirement estimates, so the data were pooled to generate a mean of 5.1 mg/kg/d (Rm2 = 0.46, Rc2 = 0.77; p < 0.01; 95% CI: 3.67, 6.53 mg/kg/d). This is the first study to estimate the minimum methionine requirement in healthy older adults, which is the same between the sexes and as our lab's previous estimate in young adults. The findings are relevant considering current recommendations for increased consumption of plant foods, which will help to establish the appropriate balance of methionine and cysteine intake required to satisfy the sulphur amino acid requirements of older adults.

A protocol for a proof-of-concept randomized control trial testing increased protein quantity and quality in ready-to-use therapeutic food in improving linear growth among 6-23-month-old children with severe wasting in Malawi.

INTRODUCTION: Ready-to-use therapeutic foods (RUTFs) have successfully promoted recovery from severe wasting and increased treatment coverage. However, RUTFs do not sufficiently improve linear growth, leaving many survivors of severe wasting at risk of persistent stunting, which is associated with high mortality risk, poor child development and non-communicable diseases in adulthood. High protein quantity and quality can stimulate linear growth. AIM: The trial aims to assess whether higher-protein-RUTF leads to higher concentrations of markers of linear growth compared to standard RUTF among 6-23 months old children with severe wasting. METHODS: We designed a higher protein quantity and quality RUTF for a proof-of-concept (PoC) double-blind randomized controlled trial. OUTCOMES: The primary outcome is a change in insulin-like growth factor-1 (IGF-1), a hormone positively associated with linear growth after four weeks of treatment. Secondary outcomes include changes in ponderal and linear growth and in body composition from baseline to eight weeks later; plasma amino acid profile at four weeks; acceptability and safety. IMPLICATIONS: These findings will help in informing the potential impact of increased protein in RUTF on linear growth when treating severe wasting towards conducting a larger clinical trial. TRIAL REGISTRATION: The trial has been registered on clinicaltrial.gov (NCT05737472).

Composite lipid emulsion use and essential fatty acid deficiency in pediatric patients with intestinal failure with high parenteral nutrition dependence: A retrospective cohort study.

BACKGROUND: Reports of essential fatty acid deficiency (EFAD) in patients receiving parenteral nutrition (PN) and a composite lipid (mixed oil intravenous lipid emulsion [MO ILE]) are predominantly when managed by lipid restriction. The objective of this study was to determine the prevalence of EFAD in patients with intestinal failure (IF) who are PN dependent without lipid restriction. METHODS: We retrospectively evaluated patients, ages 0-17 years, followed by our intestinal rehabilitation program between November 2020 and June 2021 with PN dependency index (PNDI) of >80% on a MO ILE. Demographic data, PN composition, PN days, growth, and plasma fatty acid profile were collected. A plasma triene-tetraene (T:T) ratio >0.2 indicated EFAD. Summary statistics and Wilcoxon rank sum test evaluated to compare between PNDI category and ILE administration (grams/kilograms/day). P < 0.05 was considered significant. RESULTS: Twenty-six patients (median age, 4.1 years [interquartile range (IQR) = 2.4-9.6]) were included. The median duration of PN was 1367 days (IQR = 824-3195). Sixteen patients had a PNDI of 80%-120% (61.5%). Fat intake for the group was 1.7 g/kg/day (IQR = 1.3-2.0). The median T:T ratio was 0.1 (IQR = 0.1-0.2) with no values >0.2. Linoleic and arachidonic acid were low in 85% and 19% of patients, respectively; however, Mead acid was normal in all patients. CONCLUSION: This report is the largest to date on the EFA status of patients with IF on PN. These results suggest that, in the absence of lipid restriction, EFAD is not a concern when using MO ILEs in children receiving PN for IF.

Body Composition and Physical Activity in Pediatric Intestinal Failure On and Off Parenteral Nutrition.

OBJECTIVES: Data on the relationship between body composition (BC) and physical activity (PA) in children with intestinal failure (IF) are lacking. The objectives were to collect data on PA and BC in children with IF, both parenterally and enterally fed, and to assess the relationship between PA and BC. METHODS: Cross-sectional study in children 5-18 years with IF including those receiving parenteral nutrition (PN) and those fully enterally fed. PA levels were measured using accelerometry. BC was measured by dual-energy X-ray absorptiometry. Data were compared to age- and sex-matched population norms using t tests. Regression analysis assessed the relationship between BC and PA. RESULTS: Fifty-eight children with IF (38 males), mean (SD) age of 10.0 (3.5) years, 20 dependent on PN were included. Patients with IF had significantly fewer steps per day ( P ≤ 0.001) compared with literature controls, with a mean (SD) of 7,972 (3,008) and 11,749 (1,106), respectively. There were no significant differences between patients receiving PN and those enterally fed, but both groups were significantly less active than literature controls ( P < 0.001). Patients with IF had higher fat mass and lower fat-free mass compared to literature controls ( P = 0.008). PA had a significant effect on BC ( r2 = 0.32, P < 0.001). CONCLUSIONS: Children with IF, those receiving PN and those fully enterally fed, are at risk of decreased PA and altered BC. PA should be part of ongoing rehabilitation and management to optimize outcomes.

Assessment of body composition in pediatric intestinal failure: A comparison study.

BACKGROUND: The objective of the study was to compare bioelectrical impedance analysis (BIA) and skinfolds with dual energy x-ray absorptiometry (DXA) in the assessment of body composition of children with intestinal failure. DXA is the reference method for body composition assessment in clinical settings. METHODS: Children aged 1-18 years with intestinal failure whohave DXA as part of routine clinical monitoring were eligible. BIA measured total body water on the same day as DXA. Skinfold measurements were taken at four sites: triceps, biceps, subscapular, and suprailiac. Percentage of fat mass (%FM) and fat-free mass (%FFM) were derived from resistance and reactance measured by BIA by using age-specific equations. Percentage of FM was calculated from skinfold measures by using age-specific equations. Data on patient characteristics, intestinal failure-related factors, and feeding method were collected. Paired t test examined differences in %FM and %FFM and Bland-Altman analysis determined the agreement between BIA, skinfolds, and DXA. Marginal linear model assessed the effect of age, sex, and feeding method on the difference in body composition obtained between DXA and BIA and between DXA and skinfolds. RESULTS: Sixty-eight children with intestinal failure, mean age 8.9 ± 4.2 years, were studied. There was no difference between %FFM and %FM obtained by DXA and BIA (P = 0.26), with a mean bias (95% CI) of -0.69 (-1.9 to 0.5) for %FFM. Sex and age were individually and jointly associated with the bias observed between DXA and BIA (P < 0.05). Skinfold and DXA measurements were significantly different (P < 0.05). CONCLUSIONS: BIA is an acceptable clinical tool for assessing body composition in pediatric intestinal failure.

The dietary requirement for total sulfur amino acids in adults aged ≥60 years appears to be higher in males than in females.

BACKGROUND: The total sulfur amino acid (TSAA) recommendation in older adults is based on data from young adults. Physiological evidence suggests that older adults have a higher requirement than young adults. OBJECTIVES: The objective of this study was to determine the TSAA requirement in healthy men and women aged ≥60 y. METHODS: The TSAA requirement was determined using the indicator amino acid oxidation method with L-[1-13C]phenylalanine as the indicator. At recruitment, 15 older adults (n = 7 men and n = 8 women; BMI < 30 kg/m2) were assigned to receive 7 methionine intakes (5, 10, 15, 19, 25, 35, and 40 mg/kg/d) without dietary cysteine. Intake levels were randomly assigned to each subject. Following enrollment, 2 subjects completed 2 intakes and 3 completed 3, while the remainder completed all 7. Mean TSAA requirement was determined from oxidation of L-[1-13C]phenylalanine using a mixed-effect change-point model. The 95% CI was calculated using parametric bootstrap. To test whether breakpoints were different between men and women, the overlap in the 95% CI was calculated. RESULTS: The mean TSAA requirement was 26.2 (Rm2 = 0.39, Rc2 = 0.89; P < 0.001) and 17.1 mg/kg/d (Rm2 = 0.22, Rc2 = 0.79; P < 0.001) for men and women, respectively. The requirement was significantly higher in men than in women (difference in CI: 9.1 ± 8.85). CONCLUSIONS: To our knowledge, this is the first study to determine the TSAA requirement in older adults. The requirement in older women is similar to current recommendations but is 75% higher in older men. These findings are important given recommendations for increased plant protein consumption. They will help in the assessment of diet quality and provide the basis of dietary guidelines for older adults consuming a plant-based diet. This trial was registered at clinicaltrials.gov as NCT04595188.

Length of Adaptation Has No Effect on the Threonine Requirement Determined in Healthy Young Adult Males Using the Indicator Amino Acid Oxidation Method.

BACKGROUND: The indicator amino acid oxidation (IAAO) method is minimally invasive; therefore, it is applicable to study the amino acid (AA) requirements of individuals in various age groups. However, the accuracy of this method has been criticized because of the 8 h (1 d) protocol, which has been suggested to be too short an adaptation time for estimating AA requirements. OBJECTIVES: The IAAO method was used to determine whether 3 or 7 d of adaptation to each threonine intake alters the threonine requirement in adult men compared to 1 d of adaptation. METHODS: Eleven healthy adult men (19-35 y, body mass index (BMI) 23.4 in kg⋅m-2) were studied at 6 threonine intakes; each intake was studied over a 9 d period. Following 2 d of pre-adaptation to adequate protein intake (1.0 g·kg-1⋅d-1), subjects received experimental diets containing the randomly assigned test threonine intake (5, 10, 15, 20, 25, or 35 mg·kg-1·d-1) for 7 d. IAAO studies were performed on days 1, 3, and 7 of adaptation to the experimental diet. The rate of release of 13CO2 from the oxidation of L-[1-13C]phenylalanine (F13CO2) was measured, and the threonine requirement was determined by applying mixed-effect change-point regression to the F13CO2 data in R version 4.0.5. The 95% confidence interval (CI) was calculated using parametric bootstrap, and the requirement estimates on days 1, 3, and 7 were compared using analysis of variance (ANOVA). RESULTS: The mean threonine requirements (upper, lower 95% CI) for days 1, 3, and 7 were 10.5 (5.7, 15.9), 10.6 (7.5, 13.7), and 12.1 (9.2, 15.0 mg·kg-1·d-1), respectively; and these requirements were not statistically different (P = 0.213). CONCLUSIONS: We demonstrated that the short, 8 h IAAO protocol results in a threonine requirement that is not statistically different from that obtained on days 3 or 7 of adaptation in healthy adult males. This trial was registered at www. CLINICALTRIALS: gov as NCT04585087.

Applying the indicator amino acid oxidation technique in the domestic cat: results of a pilot study and development of a non-steady state prediction model.

The aim of this study was to evaluate whether the indicator amino acid oxidation (IAAO) method could be applied in the domestic cat. Six adult male cats were used in a replicated 3 × 3 Latin square design. Three semi-synthetic diets were developed: a methionine (Met) and total sulfur AA (TSAA) deficient diet (T-BASAL; 0.24% Met+Cys - DM basis) and two Met and TSAA-sufficient diets in which either dl-Met (T-DLM) or 2-hydroxy-4-(methylthio)-butanoic acid (T-MHA) were supplemented, respectively, on an equimolar basis to meet the TSAA requirement (0.34%). After a 2-d diet adaptation, IAAO studies were performed. Cats were offered 13 small meals. The sixth meal contained a priming dose (4.8 mg/kg-BW) of l-[1-13C]-Phe and the remaining meals a constant dose (1.04 mg/kg-BW). Breath samples were collected every 25 min to measure 13CO2 enrichment. The following morning, fasted blood samples were collected. Cats returned to the T-BASAL top dressed with a dl-Met solution for 4 d prior to being fed a new dietary treatment. Isotopic steady state was evaluated through visual inspection. Data were analyzed using PROC GLIMMIX procedure in SAS 9.4. While 13CO2 enrichment was successfully captured in breath samples, cats failed to reach 13CO2 steady state. Thus, a non-steady state isotope model was developed and coded in ACSLX (V3.1.4.2) individually for each cat on each study day to predict 13CO2 enrichment, and then, calculate oxidation of l-[1-13C]-Phe (F13CO2). A higher predicted F13CO2 was observed for cats fed T-BASAL compared to the others (P < 0.05), while no differences were observed between T-DLM and T-MHA (P > 0.05). Cats fed T-DLM tended to have higher plasma Met concentrations compared to those fed T-BASAL with cats fed T-MHA intermediate (P = 0.0867). Plasma homocysteine concentrations were higher in cats fed T-BASAL compared to the others (P < 0.05), while threonine concentrations tended to be higher in cats fed T-BASAL compared to those fed T-MHA (P = 0.0750). In conclusion, short-term provision of a semi-synthetic diet deficient in Met may elicit a metabolic response aiming to conserve Met. The successful quantification of 13CO2 enrichment in breath and the higher predicted F13CO2 in cats fed a Met deficient diet suggest that the IAAO technique may be used in cats. Adaptations in the isotope protocol should be made to achieve 13CO2 steady state in breath and avoid mathematical modeling to predict F13CO2.

It is necessary to apply more sensitive techniques to improve our limited understanding of amino acid (AA) requirements of adult cats. The non-invasive indicator amino acid oxidation (IAAO) technique is highly sensitive in mature animals. However, while it has been widely applied in different species, this technique has yet to be used in cats. We used six healthy adult cats to evaluate whether the IAAO method could be successfully applied in this species. A similar continuous small meals regimen as reported in IAAO studies in dogs was used. An oral primed-constant isotope infusion protocol was applied where l-13C-Phenylalanine (l-[1-13C]-Phe) was used as the tracer and the oxidation of l-[1-13C]-Phe as the response of interest. Breath samples were collected to determine enrichment of 13CO2 in breath and calculate oxidation of l-[1-13C]-Phe. While we were able to collect breath samples using calorimetry chambers and capture enrichment of 13CO2 in breath, cats did not achieve steady state, which is necessary to calculate oxidation of l-[1-13C]-Phe. Modifications in the isotope protocol should be made to achieve steady state of 13CO2 in breath, and thus, to successfully apply the IAAO technique to determine requirement of AA in adult cats.

Evaluation of standardized ileal digestibility of amino acids and metabolic availability of methionine, using the indicator amino acid oxidation method, in black soldier fly larvae (Hermetia illucens) meal fed to growing pigs.

Standardized ileal digestibility (SID, %) of crude protein (CP) and amino acid (AA) and the metabolic availability (MA) of Met using the indicator amino acid oxidation (IAAO) method, in partially defatted black soldier fly larvae (PD-BSFL) meal were determined in growing pigs in 2 experiments. The Met SID value was then compared numerically with the Met MA to understand how different SID is compared with its MA value. In Exp. 1, 6 ileal-cannulated barrows (initial body weight [BW] = 18.03 ± 0.34 kg) were used in a 2-period switch back design and fed either a nitrogen-free diet (NFD) or test diet, with PD-BSFL meal as the sole source of AA, over two 11-d experimental periods, at a feeding level of 2.8 × estimated maintenance digestible energy requirement. Barrows were adapted for 9-d to the diet, followed by continuous 8-h ileal digesta collection on day 10 and 11. Digesta were pooled per pig within period. The SID of CP and Met of PD-BSFL meal were 76.1 ± 6.2% and 90.4 ± 3.9%, respectively. In Exp. 2, 7 barrows (initial BW = 18.77 ± 0.69 kg) were used in a 7 × 7 Latin square design with L-[1-13C]-Phe as the indicator AA. Each pig was randomly assigned to 1 of 7 dietary treatments over seven 3-d experimental periods. Two diet types were studied including reference (crystalline AA) and PD-BSFL test diets, each supplying graded intakes of Met at 55, 65, and 75% of the estimated SID requirement (NRC, 2012). The MA of Met was determined by comparing the IAAO response between the reference and PD-BSFL test diet using the slope-ratio method. Linear regression determined a negative slope of the best fit line for both the reference and test diets (P < 0.05). The MA of Met in PD-BSFL meal was 53.3%, which is as expected lower than the SID value. While it is generally appreciated that MA will be less than SID, the use of SID is more practical. In cases where SID cannot explain physiological outcomes of feeding a novel ingredient, IAAO may provide additional insight into whether MA should be explored.

The interest in black soldier fly larvae (BSFL) meal as a protein ingredient in swine feed has grown in the past years. As a novel protein ingredient, it is beneficial to evaluate the amino acid (AA) digestibility and metabolic availability (MA) of the limiting AA, Met, in pigs, in BSFL meal prior to incorporation in feed for a more precise formulation. Two different methodologies were used to determine the AA digestibility and MA, standardized ileal digestibility (SID) and indicator amino acid oxidation (IAAO) method, respectively. Based on the SID values, the AA digestibility of BSFL meal, for some, but not all AA, is comparable to other commonly used protein ingredients in commercial swine feed. When compared with the MA result of Met, the Met SID value is much lower. This indicates that not all digested Met is available for protein synthesis or other metabolic processes in the animal.

Predictors of Social-Emotional Development and Adaptive Functioning in School-Age Children with Intestinal Failure.

OBJECTIVES: Despite a focus on neurocognition in pediatric intestinal failure (IF) to date, we examined social-emotional and adaptive functioning. METHODS: Children (N = 63) in our IF rehabilitation program underwent neuropsychological assessments including caregiver- and teacher-reported questionnaires. Results were compared to norms using z-tests. Caregiver and teacher reports were compared using t tests. Medical and demographic factors were examined in an exploratory manner using correlation and targeted regression analyses, adjusting for gestational age and full-scale IQ. RESULTS: Caregiver and teacher reports indicated poorer executive, internalizing, behavioral, and adaptive functioning compared to norms. Teachers reported more executive dysfunctions than caregivers. Necrotizing enterocolitis diagnosis predicted internalizing emotional problems. Immigrant status predicted poorer social and practical adaptive functioning. Living with biological parents predicted fewer externalizing emotional and behavioral problems. CONCLUSIONS: The group displayed social-emotional and adaptive functioning concerns. Identifying medical and demographic risks can allow for screening and intervention.

Amino acid oxidation methods to determine amino acid requirements: do we require lengthy adaptation periods?

Determination of indispensable amino acid (IAA) requirements necessitates a range of intakes of the test IAA and monitoring of the physiological response. Short-term methods are the most feasible for studying multiple intake levels in the same individual. Carbon oxidation methods measure the excretion of 13CO2 in breath from a labelled amino acid (AA) in response to varying intakes of the test AA following a period of adaptation. However, the length of adaptation to each AA intake level has been a source of debate and disagreement among researchers. The assertion of the minimally invasive indicator amino acid oxidation (IAAO) technique is that IAA requirements can be estimated after only a few hours (8 h) of adaptation to each test AA intake, suggesting that adaptation occurs rapidly in response to dietary adjustments. On the contrary, the assertion of most other techniques is that 6-7 d of adaptation is required when determining IAA needs. It has even been argued that a minimum of two weeks is needed to achieve complete adaptation. This review explores evidence regarding AA oxidation methods and whether long periods of adaptation to test IAA levels are necessary when estimating IAA requirements. It was found that the consumption of experimental diets containing lower test IAA intake for greater than 7 d violates the terms of a successful adaptive response. While there is some evidence that short-term 8 h IAAO is not different among different test amino acid intakes up to 7 d, it is unclear whether it impacts assessment of IAA requirements.

Muscle Strength, Agility, and Body Composition in Children With Intestinal Failure on Parenteral Nutrition.

OBJECTIVES: With increasing number of children with intestinal failure (IF) on long-term parenteral nutrition (PN), this study assesses the impact of IF on muscle strength, speed, and agility and body composition (BC), identifying clinical factors that may predict impairment. METHODS: Cross-sectional study in children 5-18 years with IF on PN. Assessments included Bruininks-Oseretsky Test of Motor Proficiency-2 strength and agility subtest (BOT-2), and grip strength. BC data from dual-energy x-ray absorptiometry (DXA) measurements and clinical variables were collected by chart abstraction. Data were compared to age and sex matched controls and population norms. RESULTS: Twenty-one children with IF (14 males), median age 8.33 (IQR: 6.96-11.04) years and 33 controls (20 males), 8.25 (6.67-10.79) years were included. Strength and agility ( P < 0.001) and grip strength ( P = 0.001) differed between groups. Nine of 21 (43%) of children with IF scored >1 standard deviation (SD) below mean on BOT-2 and 13 of 21 (62%) had grip strength >1 SD below mean. DXA measurements showed 10 of 18 (56%) of children had lower fat-free mass (FFM)% and higher fat mass (FM)% than reference norms. Decreased FFM% was associated with lower BOT-2 scores ( r = 0.479; P = 0.044) and grip strength scores >1 SD below mean ( P = 0.047). Additional clinical factors significantly impacting strength and agility included prematurity, height, hospitalizations, sepsis, and small bowel length. CONCLUSIONS: Children with IF are at risk of decreased muscle strength and agility, along with altered BC. Ongoing medical, nutritional, and rehabilitation intervention is vital to optimize outcomes.

Metabolic Availability of Methionine Assessed Using Indicator Amino Acid Oxidation Method, Is Greater when Cooked Lentils and Steamed Rice Are Combined in the Diet of Healthy Young Men.

BACKGROUND: Lentil is considered a high protein source. However, it is low in sulphur amino acids (SAA) and their metabolic availability (MA) is further affected by antinutritional factors in lentils. The combination of lentils with grains such as rice can enhance the protein quality of a lentil-based meal but the MA of SAA in lentils must first be known. OBJECTIVES: The objectives of the current study were to assess the MA of methionine in lentils and to test the effects of consumption of complementing lentils with rice in young adults. METHODS: Five healthy young men [age <30 y, BMI <25 (in kg/m2)] were each studied at 8 or 10 intake amounts of methionine in random order; 4 daily intake amounts of l-methionine: 0.5, 1, 2, and 3 mg.kg-1.d-1 (reference diet), 3 daily intake amounts of methionine from lentils, and 3 daily intake amounts of the mixed meal of lentils + rice (test diets). The MA of methionine and the effects of complementation were assessed by comparing the indicator amino acid oxidation (IAAO) response to varying intakes of methionine in cooked Canadian lentils, and in rice + lentils combined, compared with the IAAO response to l-methionine intakes in the reference protein (crystalline AA mixture patterned after egg protein) using the slope ratio method. l-[1-13C] phenylalanine was used as the indicator. Data were analyzed using the procedure "MIXED" with subject as a random variable, and oxidation day as repeated measure. RESULTS: The MA of methionine from lentils was 69%. Complementation of cooked lentils with rice decreased the oxidation of l-[1-13C] phenylalanine by up to 16% (P < 0.05). CONCLUSIONS: The content and MA of methionine are low in lentils. However, combination of lentils with rice in a 1:1 ratio can improve the protein quality of lentil-based diets, resulting in increased protein synthesis in young healthy adults. This trial was registered at www.clinical trials.gov as NCT03110913.

Normal anthropometry does not equal normal body composition in pediatric intestinal failure.

BACKGROUND: Published reports on abnormal body composition in pediatric patients with intestinal failure have been in patients with poor growth. The goal of the current study is to report the body composition of normally growing patients with intestinal failure. METHODS: Children 8-18 years old with a dual-energy x-ray absorptiometry (DXA) between January 1, 2013, and July 15, 2018, were included in the study. Data were retrospectively collected from the medical charts and included demographics, residual bowel anatomy, nutrition support, height, and weight. DXA data, including total body less head bone mineral density (BMD), fat mass (FM), and fat-free mass (FFM), were collected and compared with published literature controls matched for age and sex. RESULTS: Thirty-four children met inclusion criteria. Mean age at the time of DXA was 9.6 ± 1.8 years. Weight- and height-for-age z-scores were -0.4 ± 0.9 and -0.5 ± 1.0, respectively. Mean BMD z-score was -1.0 ± 1.3. Twenty-six percent of patients (n = 9) had reduced BMD. Patients with intestinal failure had higher FM (P = .02) and lower FFM (P = .02) compared with controls. CONCLUSIONS: These data show that, despite reference range z-scores for height and weight, children with intestinal failure are at risk for abnormal body composition. Body composition should be routinely measured in children with intestinal failure to direct nutrition interventions.