Dietary cysteine is used more efficiently by children with severe acute malnutrition with edema compared with those without edema

The impact of obesity-associated glycine deficiency on the elimination of endogenous and exogenous metabolites via the glycine conjugation pathway

Background

Glycine is an integral component of the human detoxification system as it reacts with potentially toxic exogenous and endogenously produced compounds and metabolites via the glycine conjugation pathway for urinary excretion. Because individuals with obesity have reduced glycine availability, this detoxification pathway may be compromised. However, it should be restored after bariatric surgery because of increased glycine production.

Objective

To examine the impact of obesity-associated glycine deficiency on the glycine conjugation pathway. We hypothesize that the synthesis rates of acylglycines from endogenous and exogenous sources are significantly reduced in individuals with obesity but increase after bariatric surgery.

Methods

We recruited 21 participants with class III obesity and 21 with healthy weight as controls. At baseline, [1,2-13C2] glycine was infused to study the glycine conjugation pathway by quantifying the synthesis rates of several acylglycines. The same measurements were repeated in participants with obesity six months after bariatric surgery. Data are presented as mean ± standard deviation, and p-value< 0.05 is considered statistically significant.

Results

Baseline data of 20 participants with obesity were first compared to controls. Participants with obesity were significantly heavier than controls (mean BMI 40.5 ± 7.1 vs. 20.8 ± 2.1 kg/m2). They had significantly lower plasma glycine concentration (168 ± 30 vs. 209 ± 50 μmol/L) and slower absolute synthesis rates of acetylglycine, isobutyrylglycine, tigylglycine, isovalerylglycine, and hexanoylglycine. Pre- and post-surgery data were available for 16 participants with obesity. Post-surgery BMI decreased from 40.9 ± 7.3 to 31.6 ± 6.0 kg/m2. Plasma glycine concentration increased from 164 ± 26 to 212 ± 38 μmol/L) and was associated with significantly higher rates of excretion of acetylglycine, isobutyrylglycine, tigylglycine, isovalerylglycine, and hexanoylglycine. Benzoic acid (a xenobiotic dicarboxylic acid) is excreted as benzoylglycine; its synthesis rate was significantly slower in participants with obesity but increased after bariatric surgery.

Conclusion

Obesity-associated glycine deficiency impairs the human body's ability to eliminate endogenous and exogenous metabolites/compounds via the glycine conjugation pathway. This impairment is ameliorated when glycine supply is restored after bariatric surgery. These findings imply that dietary glycine supplementation could treat obesity-associated metabolic complications due to the accumulation of intramitochondrial toxic metabolites.

Clinical trial registration

https://clinicaltrials.gov/study/NCT04660513, identifier NCT04660513.

Metabolite Comparison between Spleen-Deficiency and Healthy Children

Objective

From the perspective of metabolomics, this study compares the metabolomics characteristics of feces and urine between children with spleen-deficiency and healthy children to explain the scientific connotation of children with spleen-deficiency susceptibility to digestive system diseases from the metabolic level and provide a scientific basis for further research.

Methods

This study included 20 children with spleen-deficiencies and 17 healthy children. Children's symptom scores, height, and weight were recorded in groups, and feces and urine samples were collected. The samples were detected using ultrahigh-performance liquid chromatography-mass spectrometry. The data were analyzed using multivariate statistical analysis such as principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA). Related differential metabolites were identified through database comparisons between two groups based on the MS and KEGG.

Results

Compared to healthy children, the metabolites glucuronic acid, xanthine, and indole-3-acetaldehyde tend to be reduced in children with spleen-deficiency. Moreover, these children showed an increase in metabolites such as quinic acid, adenine, 4-methyl-5-thiazole-ethanol, 3-formyl indole, and 5-hydroxy indole-3-acetic acid. The condition affected many of the critical metabolic pathways, including the metabolism of tryptophan, cysteine, methionine, and pentose phosphate.

Conclusion

The children with spleen-deficiency had disorders at the metabolic level, which might be due to factors such as diet, personal preferences, and genes, leading to various symptoms, making spleen-deficiency children more prone to suffer from digestive diseases than healthy children. The results set a basis for the research on children's TCM constitution, which can be a reference to further studies to deal with the spleen-deficiency.

Photoacoustic/Fluorescence Dual-Modality Probe for Biothiol Discrimination and Tumor Diagnosis in Cells and Mice

Developing probes to simultaneously detect and discriminate biothiols is important, yet challenging. Activatable photoacoustic (PA) probes for discriminating biothiols in vivo are still lacking, and this hinders the diagnosis of thiol-related diseases. Herein we present the first PA and fluorescence dual-modality probe MB-NBD for discriminating different biothiol species. The probe has the advantages of both fluorescence imaging and PA imaging (high sensitivity and deep penetration) with distinct signal patterns toward hydrogen sulfide (H₂S), cysteine/homocysteine (Cys/Hcy), and glutathione (GSH) treatment. The biothiol-activated product of MB-NBD exhibits enhancements in near-infrared fluorescence (NIRF) at 690 nm and absorbance/PA at 664 nm upon fast reaction, allowing it to selectively detect biothiol species over other reactive species. On the other hand, MB-NBD displays characteristic absorbance enhancement at 547 nm toward H₂S, rendering specific detection of H₂S. In addition, the specific enhancements in absorbance/PA at 470 nm and fluorescence at 550 nm toward Cys/Hcy treatment endows the probe with the capability of selectively detecting Cys/Hcy. Furthermore, MB-NBD is able to discriminate Cys and GSH by fluorescent imaging in live-cell and ratiometric PA imaging in mice experiments. MB-NBD has been successfully used to diagnose tumors by dual-channel ratiometric PA imaging.

Rapid determination of cysteine and chiral discrimination of D-/L-cysteine via the aggregation-induced emission enhancement of gold nanoclusters by Ag. ANAL SCI 2022;38:541-551. [PMID: 35359272 DOI: 10.2116/analsci.21p207]

Cysteine (Cys) plays vital roles in various physiological and pathological functions. Either a deficiency or excess of Cys could lead to severe ailments in human. The identification and determination of Cys are the key issues for the early diagnosis of relevant diseases. This contribution has presented a promising potential of fluorescent gold nanoclusters (AuNCs) for Cys determination and D-/L-Cys enantiomer discrimination. Cys determination and discrimination are involved three steps. First, as a reducing and capping ligand, glutathione was applied to fabricate weak fluorescent AuNCs. Second, Ag+ was introduced to lead the aggregation-induced emission (AIE) to form well-dispersed aggregates. The fluorescence intensity of AuNCs was monitored at excitation/emission wavelengths of 396/620 nm. Third, Cys was found to quickly bind with Ag+ to form a grid network to light up the system via aggregation-induced emission enhancement (AIEE). A novel sensor for a sensitive and a visually selective detection of Cys was established on the basis of the AIEE mechanism. Rapid quantitative determination of Cys was achieved in 2 min via AIEE within the range of 0.5-100 μmol L-1 and a detection limit of 0.365 μmol L-1. Moreover, due to the specific interactions of D-/L-Cys with mandelic acid and tartaric acid, the visual discrimination of D-/L-Cys enantiomers with naked eyes was realized by replacing the organic acid buffer.

Cysteine exerts an essential role in maintaining intestinal integrity and function independent of glutathione

SCOPE

Enteral feeding is a primary source of cysteine for intestinal mucosa given negligible transsulfuration activity in enterocytes and furthermore very few cysteine uptake from arterial blood. This study aims to explore the role of cysteine in maintaining intestinal integrity and function.

METHODS AND RESULTS

The intestinal porcine enterocytes (IPEC-J2) were cultured in a cysteine-deprived medium with or without glutathione supplementation upon the inhibitions of glutathione synthesis or degradation. As a result, cysteine deprivation impaired mitochondrial function, suppressed mechanistic target of rapamycin (mTOR) signaling and activated general control nonderepressible 2 (GCN2) signaling, and might lead to resultant ferroptosis. Glutathione supplementation could restore the impairment through degradating into cysteine, while glutathione synthesis inhibition did not disturb the role of cysteine in keeping the intestinal epithelial cells. Furthermore, piglets were fed with cysteine-deficient, -adequate and -surplus diet for 28 d as a porcine model. We evidenced that intestinal integrity and individual growth benefit from adequate dietary cysteine.

CONCLUSION

Adequate dietary cysteine supply is essential for intestinal mucosal integrity, epithelial cell turnover and amino acid sensing as well as optimal individual growth. Cysteine exerts its role independent of glutathione and glutathione restores the impairment of cysteine-deprivation on intestinal mucosal through degrading into cysteine. This article is protected by copyright. All rights reserved.

Mitochondria-targeted ratiometric fluorescent imaging of cysteine

As an indispensable biothiol, cysteine (Cys) plays a critical part in cellular redox homeostasis, and pathological and physiological processes. One of the main sources of reactive oxygen species (ROS) in human cells is the substrate end of the respiratory chain in the mitochondrial inner membrane. Therefore, it is valuable to develop probes targeting mitochondria to detect Cys. In this work, we designed a novel fluorescent probe, 2-(2-(6-(acryloyloxy) naphthalen-2-yl) vinyl)-3-ethylbenzothiazol-3-ium (ANET). The naphthyl benzothiazole is the fluorophore group and the acrylate moiety is the Cys response site to avoid the interference of homocysteine (Hcy) and glutathione (GSH). ANET combines multiple strengths for detecting Cys: targeting mitochondria, ratiometric fluorescence, high selectivity, and a large Stokes shift. After ANET reacted with Cys, the fluorescence signals changed from green (λem = 525 nm) to orange red (λem = 595 nm), and the detection limit was calculated to be 74 nM through a linear relationship between ratiometric fluorescence F595/F525 and Cys concentration. The imaging of Cys was confirmed in HepG2 cells.

Effects of dietary iron level on growth performance, hematological status, and intestinal function in growing-finishing pigs

This study investigated the different addition levels of iron (Fe) in growing-finishing pigs and the effect of different Fe levels on growth performance, hematological status, intestinal barrier function, and intestinal digestion. A total of 1,200 barrows and gilts ([Large White × Landrace] × Duroc) with average initial body weight (BW; 27.74 ± 0.28 kg) were housed in 40 pens of 30 pigs per pen (gilts and barrows in half), blocked by BW and gender, and fed five experimental diets (eight replicate pens per diet). The five experimental diets were control diet (basal diet with no FeSO4 supplementation), and the basal diet being supplemented with 150, 300, 450, or 600 mg/kg Fe as FeSO4 diets. The trial lasted for 100 d and was divided into the growing phase (27 to 60 kg of BW) for the first 50 d and the finishing phase (61 to 100 kg of BW) for the last 50 d. The basal diet was formulated with an Fe-free trace mineral premix and contained 203.36 mg/kg total dietary Fe in the growing phase and 216.71 mg/kg in the finishing phase based on ingredient contributions. And at the end of the experiment, eight pigs (four barrows and four gilts) were randomly selected from each treatment (selected one pig per pen) for digesta, blood, and intestinal samples collection. The results showed that the average daily feed intake (P = 0.025), average daily gain (P = 0.020), and BW (P = 0.019) increased linearly in the finishing phase of pigs fed with the diets containing Fe. On the other hand, supplementation with different Fe levels in the diet significantly increased serum iron and transferrin saturation concentrations (P < 0.05), goblet cell numbers of duodenal villous (P < 0.001), and MUC4 mRNA expression (P < 0.05). The apparent ileal digestibility (AID) of amino acids (AA) for pigs in the 450 and 600 mg/kg Fe groups was greater (P < 0.05) than for pigs in the control group. In conclusion, dietary supplementation with 450 to 600 mg/kg Fe improved the growth performance of pigs by changing hematological status and by enhancing intestinal goblet cell differentiation and AID of AA.

Association of Plasma Total Cysteine and Anthropometric Status in 6-30 Months Old Indian Children

High-quality protein has been associated with child growth; however, the role of the amino acid cysteine remains unclear. The aim was to measure the extent to which plasma total cysteine (tCys) concentration is associated with anthropometric status in children aged 6–30 months living in New Delhi, India. The study was a prospective cohort study including 2102 children. We calculated Z-scores for height-for-age (HAZ), weight-for-height (WHZ), or weight-for-age (WAZ) according to the WHO Child Growth Standards. We used multiple regression models to estimate the association between tCys and the anthropometric indices. A high proportion of the children were categorized as malnourished at enrolment; 41% were stunted (HAZ ≤ −2), 19% were wasted (WHZ ≤ −2) and 42% underweight (WAZ ≤ −2). Plasma total cysteine (tCys) was significantly associated with HAZ, WHZ and WAZ after adjusting for relevant confounders (p < 0.001). Low tCys (≤25th percentile) was associated with a decrease of 0.28 Z-scores for HAZ, 0.10 Z-scores for WHZ, and 0.21 Z-scores for WAZ compared to being >25th percentile. In young Indian children from low-to-middle socioeconomic neighborhoods, a low plasma total cysteine concentration was associated with an increased risk of poor anthropometric status.

Methionine Nutrition and Metabolism: Insights from Animal Studies to Inform Human Nutrition

Methionine is a nutritionally indispensable amino acid, and is unique among indispensable amino acids due to its sulfur atom. Methionine is involved in cysteine synthesis via the transsulfuration pathway, which is rate limiting for the key antioxidant molecule, glutathione. Methionine is also the primary methyl donor in the body through S-adenosylmethionine via the transmethylation pathway, which is involved in the synthesis of several key metabolites including creatine and phosphatidylcholine. Methionine can also be remethylated from homocysteine, in the presence of betaine via choline and/or folate. Thus methionine demands from a dietary perspective are regulated not only by the presence of cysteine in the body, but also by the demands in vivo for the various metabolites formed from it, and also by the presence of these compounds in foods. Indeed, methionine, cysteine, and the various methyl donors/acceptors vary in human foods, and thus regulate methionine availability, especially under conditions of growth and development. Much of our understanding of methionine nutrition and metabolism arises from experiments in animal models. This is because most animal feed formulations are plant-based and plant sources are relatively low in methionine and cysteine amounts. Thus, this brief review will touch on some broad aspects of human methionine nutrition, including requirements in different life stages, disease, and bioavailability, with some examples from the insights/lessons learned from experiments initially conducted in animals.

Association of Maternal Plasma Total Cysteine and Growth among Infants in Nepal: A Cohort Study

Cysteine is a semi-essential amino acid that has been positively associated with growth in children. However, transgenerational effects remain unclear. The aim of this analysis was to assess whether maternal plasma total cysteine (tCys) concentration is associated with various growth indicators in infants living in peri-urban settings in Bhaktapur, Nepal. We used data from the 561 mothers enrolled in an ongoing randomized controlled trial. We built linear regression models to evaluate the associations between maternal tCys and birth weight, length-for-age Z-scores (LAZ) and weight-for-length Z-scores (WLZ) at birth and six months of age. Maternal tCys was inversely associated with birth weight among boys after adjusting for confounders (p < 0.05). In addition, there was a negative association between maternal tCys and LAZ at birth (p < 0.01). No associations between maternal tCys and the other anthropometric indicators were found significant, although there was a tendency for maternal tCys to be associated positively with WLZ at birth among girls (p < 0.10). This is a first study evaluating transgenerational relation of tCys on growth in infants. Further, larger and more comprehensive studies are needed to determine if and how maternal tCys alters child growth.

Preovulatory exposure to a protein-restricted diet disrupts amino acid kinetics and alters mitochondrial structure and function in the rat oocyte and is partially rescued by folic acid

BACKGROUND

Detrimental exposures during pregnancy have been implicated in programming offspring to develop permanent changes in physiology and metabolism, increasing the risk for developing diseases in adulthood such as hypertension, diabetes, heart disease and obesity. This study investigated the effects of protein restriction on the metabolism of amino acids within the oocyte, liver, and whole organism in a rat model as well as effects on mitochondrial ultrastructure and function in the cumulus oocyte complex.

METHODS

Wistar outbred female rats 8-11 weeks of age (n = 24) were assigned to three isocaloric dietary groups, including control (C), low protein (LP) and low protein supplemented with folate (LPF). Animals were superovulated and 48 h later underwent central catheterization. Isotopic tracers of 1-¹³C-5C²H₃-methionine, ²H₂-cysteine, U-¹³C₃-cysteine and U-¹³C₃-serine were administered by a 4 h prime-constant rate infusion. After sacrifice, oocytes were denuded of cumulus cells and liver specimens were obtained.

RESULTS

Oocytes demonstrated reduced serine flux in LP vs. LPF (p < 0.05), reduced cysteine flux in LP and LPF vs. C (p < 0.05), and a trend toward reduced transsulfuration in LP vs. C and LPF. Folic acid supplementation reversed observed effects on serine flux and transsulfuration. Preovulatory protein restriction increased whole-body methionine transmethylation, methionine transsulfuration and the flux of serine in LP and LPF vs. C (p = 0.003, p = 0.002, p = 0.005). The concentration of glutathione was increased in erythrocytes and liver in LP and LPF vs. C (p = 0.003 and p = 0.0003). Oocyte mitochondrial ultrastructure in LP and LPF had increased proportions of abnormal mitochondria vs. C (p < 0.01 and p < 0.05). Cumulus cell mitochondrial ultrastructure in LP and LPF groups had increased proportions of abnormal mitochondria vs. C (p < 0.001 and p < 0.05). Preovulatory protein restriction altered oocyte expression of Drp1, Opa-1, Mfn1/2, Parl and Ndufb6 (p < 0.05) and Hk2 (p < 0.01), which are genes involved in mitochondrial fission (division) and fusion, mitochondrial apoptotic mechanisms, respiratory electron transport and glucose metabolism.

CONCLUSIONS

Preovulatory protein restriction resulted in altered amino acid metabolism, abnormal cumulus oocyte complex mitochondrial ultrastructure and differential oocyte expression of genes related to mitochondrial biogenesis.

A colorimetric sensor of cysteine based on self-assembly nanostructures of Fe3+-H2O2/Tetramethylbenzidine system with "On-Off" switching function

Many strategies have been explored for selectively and sensitively detecting cysteine in different samples. Here, a novel colorimetric sensor based on self-assembly nanostructures of Fe³⁺-H₂O₂/Tetramethylbenzidine system with dual-level logic gate function and colorimetric determination of cysteine were firstly explored. The proposed Fe³⁺-H₂O₂-TMB system provides a sensitive optical signal due to the selectively reductive ability of cysteine to the oxidized TMB and thus could be successfully applied to the construction of instant on-site visual detection method with a paper based test strip for cysteine determination in a sample solution as well as for a dual-level logic gate fabrication.

Combined Vitamin B-12 and Balanced Protein-Energy Supplementation Affect Homocysteine Remethylation in the Methionine Cycle in Pregnant South Indian Women of Low Vitamin B-12 Status

Background: Low-quality dietary protein intake and vitamin B-12 deficiency could interact to decrease methionine transmethylation and remethylation rates during pregnancy and may affect epigenetic modifications of the fetal genome.Objective: The objective of this randomized, partially open-labeled intervention trial was to examine the effect of supplemental high-quality protein and vitamin B-12 on third-trimester methionine kinetics in pregnant Indian women with a low vitamin B-12 status.Methods: Pregnant women with low serum vitamin B-12 concentrations (<200 pmol/L) were randomly assigned to 1 of 3 groups: the first group received balanced protein-energy supplementation of 500 mL milk/d plus a 10-μg vitamin B-12 tablet/d (M+B-12 group; n = 30), the second group received milk (500 mL/d) plus a placebo tablet (M+P group; n = 30), and the third group received a placebo tablet alone (P group; n = 33). Third-trimester fasting plasma amino acid kinetics were measured by infusing 1-¹³C,methyl-²H₃-methionine, ring-²H₅-phenylalanine, ring-²H₄-tyrosine,1-¹³C-glycine, and 2,3,3-²H₃,¹⁵N-serine in a subset of participants. Placental mRNA expression of genes involved in methionine pathways, placental long interspersed nuclear elements 1 (LINE-1) methylation, and promoter methylation levels of vascular endothelial growth factor (VEGF) were analyzed.Results: Remethylation rates in the M+B-12, M+P, and P groups were 5.1 ± 1.7, 4.1 ± 1.0, and, 5.0 ± 1.4 μmol ⋅ kg^-1 ⋅ h^-1, respectively (P = 0.057), such that the percentage of transmethylation remethylated to methionine tended to be higher in the M+B-12 group (49.5% ± 10.5%) than in the M+P group (42.3% ± 8.4%; P = 0.053) but neither differed from the P group (44.2% ± 8.1%; P > 0.1). Placental mRNA expression, LINE-1, and VEGF promoter methylation did not differ between groups.Conclusions: Combined vitamin B-12 and balanced protein-energy supplementation increased the homocysteine remethylation rate in late pregnancy. Thus, vitamin B-12 along with balanced protein-energy supplementation is critical for optimal functioning of the methionine cycle in the third trimester of pregnancy in Indian women with low serum vitamin B-12 in early pregnancy. This trial was registered at clinicaltrials.gov as CTRI/2016/01/006578.

L-Cysteine metabolism and its nutritional implications

L-Cysteine is a nutritionally semiessential amino acid and is present mainly in the form of L-cystine in the extracellular space. With the help of a transport system, extracellular L-cystine crosses the plasma membrane and is reduced to L-cysteine within cells by thioredoxin and reduced glutathione (GSH). Intracellular L-cysteine plays an important role in cellular homeostasis as a precursor for protein synthesis, and for production of GSH, hydrogen sulfide (H(2)S), and taurine. L-Cysteine-dependent synthesis of GSH has been investigated in many pathological conditions, while the pathway for L-cysteine metabolism to form H(2)S has received little attention with regard to prevention and treatment of disease in humans. The main objective of this review is to highlight the metabolic pathways of L-cysteine catabolism to GSH, H(2)S, and taurine, with special emphasis on therapeutic and nutritional use of L-cysteine to improve the health and well-being of animals and humans.

Nutritional and other types of oedema, albumin, complex carbohydrates and the interstitium - a response to Malcolm Coulthard's hypothesis: Oedema in kwashiorkor is caused by hypo-albuminaemia

The various types of oedema in man are considered in relation to Starling's hypothesis of fluid movement from capillaries, with the main emphasis on nutritional oedema and the nephrotic syndrome in children. It is concluded that each condition has sufficient anomalous findings to render Starling's hypothesis untenable. The finding that the endothelial glycocalyx is key to control of fluid movement from and into the capillaries calls for complete revision of our understanding of oedema formation. The factors so far known to affect the function of the glycocalyx are reviewed. As these depend upon sulphated proteoglycans and other glycosaminoglycans, the argument is advanced that the same abnormalities will extend to the interstitial space and that kwashiorkor is fundamentally related to a defect in sulphur metabolism which can explain all the clinical features of the condition, including the formation of oedema.

Effects of randomized supplementation of methionine or alanine on cysteine and glutathione production during the early phase of treatment of children with edematous malnutrition

BACKGROUND

We have shown that a low glutathione concentration and synthesis rate in erythrocytes are associated with a shortage of protein-derived cysteine in children with edematous severe acute malnutrition (SAM).

OBJECTIVE

We tested the hypothesis that methionine supplementation may increase protein-derived cysteine and upregulate cysteine synthesis, thereby improving glutathione synthesis during the early treatment of edematous SAM.

DESIGN

The cysteine flux, its de novo synthesis and release from protein breakdown, and erythrocyte glutathione synthesis rate were measured in 12 children with edematous SAM in the fed state by using stable isotope tracers at 3 clinical phases as follows: 3 ± 1 d (±SE) [clinical phase 1 (CP1)], 8 ± 1 d [clinical phase 2 (CP2)], and 14 ± 2 d (clinical phase 3) after admission. Subjects were randomly assigned to receive equimolar supplements (0.5 mmol ⋅ kg(-1) ⋅ d(-1)) of methionine or alanine (control) immediately after CP1.

RESULTS

In the methionine compared with the alanine group, cysteine flux derived from protein breakdown was faster at CP2 than CP1 (P < 0.05), and the change in plasma cysteine concentration from CP1 to CP2 was greater (P < 0.05). However, there was no evidence of a difference in cysteine de novo synthesis and its total flux or erythrocyte glutathione synthesis rate and concentration between groups.

CONCLUSIONS

Methionine supplementation increased cysteine flux from body protein but had no significant effect on glutathione synthesis rates. Although cysteine is made from methionine, increased dietary cysteine may be necessary to partially fulfill its demand in edematous SAM because glutathione synthesis rates and concentrations were less than previous values shown at full recovery. This study was registered at clinicaltrials.gov as NCT00473031.

Dietary supplementation with aromatic amino acids increases protein synthesis in children with severe acute malnutrition

Although 2 earlier studies reported that aromatic amino acid (AAA) supplementation of children with severe acute malnutrition (SAM) improved whole-body protein anabolism during the early postadmission (maintenance) phase of rehabilitation, it is not known whether this positive effect was maintained during the catch-up growth and recovery phases of treatment. This study aimed to determine whether supplementation with an AAA cocktail (330 mg · kg(-1) · d(-1)) vs. isonitrogenous Ala would improve measures of protein kinetics in 22 children, aged 4-31 mo, during the catch-up growth and recovery phases of treatment for SAM. Protein kinetics were assessed by measuring leucine, phenylalanine, and urea kinetics with the use of standard stable isotope tracer methods in the fed state. Supplementation started at the end of the maintenance period when the children were clinically/metabolically stable and continued up to full nutritional recovery. Three experiments were performed: at the end of maintenance (at ∼13 d postadmission), at mid-catch-up growth (at ∼23 d post- admission when the children had replenished 50% of their weight deficit), and at recovery (at ∼48 d postadmission when they had achieved at least 90% weight for length). Children in the AAA group had significantly faster protein synthesis compared with those in the Ala group at mid-catch-up growth (101 ± 10 vs. 72 ± 7 μmol phenylalanine · kg(-1) · h(-1); P < 0.05) and better protein balance at mid-catch-up growth (49 ± 5 vs. 30 ± 2 μmol phenylalanine · kg(-1) · h(-1); P < 0.05) and at recovery (37 ± 8 vs. 11 ± 3 μmol phenylalanine · kg(-1) · h(-1); P < 0.05). We conclude that dietary supplementation with AAA accelerates net protein synthesis in children during nutritional rehabilitation for SAM.

Effectiveness of milk whey protein-based ready-to-use therapeutic food in treatment of severe acute malnutrition in Malawian under-5 children: a randomised, double-blind, controlled non-inferiority clinical trial

The cost of ready‐to‐use therapeutic food (RUTF) used in community‐based management of acute malnutrition has been a major obstacle to the scale up of this important child survival strategy. The current standard recipe for RUTF [peanut‐based RUTF (P‐RUTF)] is made from peanut paste, milk powder, oil, sugar, and minerals and vitamins. Milk powder forms about 30% of the ingredients and may represent over half the cost of the final product. The quality of whey protein concentrates 34% (WPC34) is similar to that of dried skimmed milk (DSM) used in the standard recipe and can be 25–33% cheaper. This blinded, parallel group, randomised, controlled non‐inferiority clinical trial tested the effectiveness in treating severe acute malnutrition (SAM) of a new RUTF formulation WPC‐RUTF in which WPC34 was used to replace DSM. Average weight gain (non‐inferiority margin Δ = −1.2 g kg⁻¹ day⁻¹) and recovery rate (Δ = −10%) were the primary outcomes, and length of stay (LOS) was the secondary outcome (Δ = +14 days). Both per‐protocol (PP) and intention‐to‐treat (ITT) analyses showed that WPC‐RUTF was not inferior to P‐RUTF for recovery rate [difference and its 95% confidence interval (CI) of 0.5% (95% CI –2.7, 3.7) in PP analysis and 0.6% (95% CI –5.2, 6.3) in ITT analysis] for average weight gain [0.2 (−0.5; 0.9) for both analyses] and LOS [−1.6 days (95% CI, −4.6, 1.4 days) in PP analysis and −1.9 days (95% CI, −4.6, 0.8 days) for ITT analysis]. In conclusion, whey protein‐based RUTF is an effective cheaper alternative to the standard milk‐based RUTF for the treatment of SAM.