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Murbach TS, Glávits R, Endres JR, Hirka G, Pasics Szakonyiné I. A 90-day preclinical toxicological evaluation in rats of a highly purified and concentrated mulberry leaf extract. J Appl Toxicol 2024. [PMID: 38837228 DOI: 10.1002/jat.4644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2024] [Revised: 04/27/2024] [Accepted: 05/06/2024] [Indexed: 06/07/2024]
Abstract
Mulberry (genus Morus) leaves have long been used as a human food, especially in Asia, and animal feed. More recently, mulberry leaf extracts have been introduced as a convenient way to consume mulberry for non-nutritional functional effects. Reducose® 5% is an Morus alba leaf extract that has been highly purified and standardized to a content of 5 ± 0.5% 1-deoxynojirimycin, a naturally present polyhydroxylated piperidine alkaloid analog of D-glucose. This extract has previously been evaluated in acute and subacute (28-day) oral toxicity studies in which no adverse effects of the test item were observed in mice or rats, respectively. Due to continued and growing interest in the extract in multinational markets, we have now further investigated potential toxic effects in subchronic (90-day) oral toxicity study in male and female Han:WIST rats. The test item was administered at doses of 850, 1700, and 2550 mg/kg bw/day, and did not cause adverse effects in clinical signs, body weight development, clinical pathology, gross pathology, or histopathology in comparison to the vehicle-control group. The no-observed-adverse-effect-level was determined to be 2550 mg/kg bw/day. These results add to the existing body of both preclinical and clinical work relevant to the safety of the extract and of interest to regulators in various global markets.
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Thondre PS, Butler I, Tammam J, Achebe I, Young E, Lane M, Gallagher A. Understanding the Impact of Different Doses of Reducose ® Mulberry Leaf Extract on Blood Glucose and Insulin Responses after Eating a Complex Meal: Results from a Double-Blind, Randomised, Crossover Trial. Nutrients 2024; 16:1670. [PMID: 38892603 PMCID: PMC11174565 DOI: 10.3390/nu16111670] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2024] [Revised: 05/23/2024] [Accepted: 05/24/2024] [Indexed: 06/21/2024] Open
Abstract
Non-communicable diseases (NCDs) are becoming an increasingly important health concern due to a rapidly ageing global population. The fastest growing NCD, type 2 diabetes mellitus (T2DM), is responsible for over 2 million deaths annually. Lifestyle changes, including dietary changes to low glycemic response (GR) foods, have been shown to reduce the risk of developing T2DM. The aim of this study was to investigate whether three different doses of Reducose®, a mulberry leaf extract, could lower the GR and insulinemic responses (IR) to a full meal challenge in healthy individuals. A double-blind, randomised, placebo-controlled, repeat-measure, crossover design trial was conducted by the Oxford Brookes Centre for Nutrition and Health; 37 healthy individuals completed the study. Participants consumed capsules containing either 200 mg, 225 mg, 250 mg Reducose® or placebo before a test meal consisting of 150 g white bread and egg mayo filler. Capillary blood samples were collected at 15-min intervals in the first hour and at 30-min intervals over the second and third hours to determine glucose and plasma insulin levels. The consumption of all three doses of Reducose® resulted in significantly lower blood glucose and plasma insulin levels compared to placebo. All three doses of Reducose® (200 mg, 225 mg, 250 mg) significantly lowered glucose iAUC 120 by 30% (p = 0.003), 33% (p = 0.001) and 32% (p = 0.002), respectively, compared with placebo. All three doses of Reducose® (200 mg, 225 mg, 250 mg) significantly lowered the plasma insulin iAUC 120 by 31% (p = 0.024), 34% (p = 0.004) and 38% (p < 0.001), respectively. The study demonstrates that the recommended dose (250 mg) and two lower doses (200 mg, 225 mg) of Reducose® can be used to help lower the GR and IR of a full meal containing carbohydrates, fats and proteins.
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Affiliation(s)
| | - Isabel Butler
- Oxford Brookes Centre for Nutrition and Health, Oxford OX3 0BP, UK; (P.S.T.); (I.B.); (J.T.); (I.A.); (E.Y.)
- Department of Paediatrics, University of Oxford, Oxford OX3 9DU, UK
| | - Jonathan Tammam
- Oxford Brookes Centre for Nutrition and Health, Oxford OX3 0BP, UK; (P.S.T.); (I.B.); (J.T.); (I.A.); (E.Y.)
| | - Ifunanya Achebe
- Oxford Brookes Centre for Nutrition and Health, Oxford OX3 0BP, UK; (P.S.T.); (I.B.); (J.T.); (I.A.); (E.Y.)
| | - Elysia Young
- Oxford Brookes Centre for Nutrition and Health, Oxford OX3 0BP, UK; (P.S.T.); (I.B.); (J.T.); (I.A.); (E.Y.)
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Van Wyk H, Lee GO, Schillinger RJ, Edwards CA, Morrison DJ, Brouwer AF. Performance of empirical and model-based classifiers for detecting sucrase-isomaltase inhibition using the 13 C-sucrose breath test. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.05.01.24306704. [PMID: 38746107 PMCID: PMC11092706 DOI: 10.1101/2024.05.01.24306704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
Background Environmental enteric dysfunction (EED) is a syndrome characterized by epithelial damage including blunting of the small intestinal villi and altered digestive and absorptive capacity which may negatively impact linear growth in children. The 13 C-sucrose breath test ( 13 C-SBT) has been proposed to estimate sucrase-isomaltase (SIM) activity, which is thought to be reduced in EED. We previously showed how various summary measures of the 13 C-SBT breath curve reflect SIM inhibition. However, it is uncertain how the performance of these classifiers is affected by test duration. Methods We leveraged SBT data from a cross-over study in 16 adults who received 0, 100, and 750 mg of Reducose, a natural SIM inhibitor. We evaluated the performance of a pharmacokinetic-model-based classifier, ρ , and three empirical classifiers (cumulative percent dose recovered at 90 minutes (cPDR90), time to 50% dose recovered, and time to peak dose recovery rate), as a function of test duration using receiver operating characteristic curves. We also assessed the sensitivity, specificity, and accuracy of consensus classifiers. Results Test durations of less than 2 hours generally failed to accurately predict later breath curve dynamics. The cPDR90 classifier had the highest area-under-the-curve and, by design, was robust to shorter test durations. For detecting mild SIM inhibition, ρ had a higher sensitivity. Conclusions We recommend SBT tests run for at least a 2-hour duration. Although cPDR90 was the classifier with highest accuracy and robustness to test duration in this application, concerns remain about its sensitivity to misspecification of CO 2 production rate. More research is needed to assess these classifiers in target populations.
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Brouwer AF, Lee GO, Van Wyk H, Schillinger RJ, Edwards CA, Morrison DJ. A Model-Based 13C-Sucrose Breath Test Diagnostic for Gut Function Disorders Characterized by a Loss of Sucrase-Isomaltase Enzymatic Activity. J Nutr 2024; 154:815-825. [PMID: 37995914 PMCID: PMC10942859 DOI: 10.1016/j.tjnut.2023.11.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Revised: 10/30/2023] [Accepted: 11/03/2023] [Indexed: 11/25/2023] Open
Abstract
BACKGROUND Environmental enteric dysfunction (EED) causes malnutrition in children in low-resource settings. Stable-isotope breath tests have been proposed as noninvasive tests of altered nutrient metabolism and absorption in EED, but uncertainty over interpreting the breath curves has limited their use. The activity of sucrose-isomaltase, the glucosidase enzyme responsible for sucrose hydrolysis, may be reduced in EED. We previously developed a mechanistic model describing the dynamics of the 13C-sucrose breath test (13C-SBT) as a function of underlying metabolic processes. OBJECTIVES This study aimed to determine which breath test curve dynamics are associated with sucrose hydrolysis and with the transport and metabolism of the fructose and glucose moieties and to propose and evaluate a model-based diagnostic for the loss of activity of sucrase-isomaltase. METHODS We applied the mechanistic model to 2 sets of exploratory 13C-SBT experiments in healthy adult participants. First, 19 participants received differently labeled sucrose tracers (U-13C fructose, U-13C glucose, and U-13C sucrose) in a crossover study. Second, 16 participants received a sucrose tracer accompanied by 0, 100, and 750 mg of Reducose, a sucrase-isomaltase inhibitor. We evaluated a model-based diagnostic distinguishing between inhibitor concentrations using receiver operator curves, comparing with conventional statistics. RESULTS Sucrose hydrolysis and the transport and metabolism of the fructose and glucose moieties were reflected in the same mechanistic process. The model distinguishes these processes from the fraction of tracer exhaled and an exponential metabolic process. The model-based diagnostic performed as well as the conventional summary statistics in distinguishing between no and low inhibition [area under the curve (AUC): 0.77 vs. 0.66-0.79] and for low vs. high inhibition (AUC 0.92 vs. 0.91-0.99). CONCLUSIONS Current summary approaches to interpreting 13C breath test curves may be limited to identifying only gross gut dysfunction. A mechanistic model-based approach improved interpretation of breath test curves characterizing sucrose metabolism.
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Affiliation(s)
- Andrew F Brouwer
- Department of Epidemiology, University of Michigan, Ann Arbor, MI, USA.
| | - Gwenyth O Lee
- Rutgers Global Health Institute, Rutgers University, New Brunswick, NJ, USA
| | - Hannah Van Wyk
- Department of Epidemiology, University of Michigan, Ann Arbor, MI, USA
| | - Robert J Schillinger
- Scottish Universities Environmental Research Centre, University of Glasgow, East Kilbride, United Kingdom; School of Medicine, Dentistry and Nursing, University of Glasgow, Glasgow, United Kingdom
| | - Christine A Edwards
- School of Medicine, Dentistry and Nursing, University of Glasgow, Glasgow, United Kingdom
| | - Douglas J Morrison
- Scottish Universities Environmental Research Centre, University of Glasgow, East Kilbride, United Kingdom
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Shivakumar N, Kelly P. Protein status in relation to linear growth faltering and environmental enteropathy. Curr Opin Clin Nutr Metab Care 2024; 27:55-60. [PMID: 37922120 DOI: 10.1097/mco.0000000000000989] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/05/2023]
Abstract
PURPOSE OF REVIEW Children with linear growth faltering refractory to nutritional management show evidence of environmental enteropathy, which may compromise nutrient availability. Protein could be particularly affected, due to the possibility of sub-optimal digestibility and/or increase in requirement for immune response. This increase in protein requirement along with poor intake could potentially lead to increased breakdown of body protein sources and in turn a depleted protein state. The present review focuses on protein status in children at risk of linear growth faltering and environmental enteropathy. One pig study is also presented. RECENT FINDINGS There is consistent evidence of low circulating essential and conditionally essential amino acids, in children. One study showed no difference in protein synthesis/breakdown, and fat free mass (FFM) in children at risk of linear growth faltering and environmental enteropathy. Weanling pigs exposed to nutrient deprivation showed a decrease in plasma albumin, with a slower rate of weight and length accretion, and a lower FFM. SUMMARY These findings emphasize the need for improving intake of high-quality protein in children living in regions with a high prevalence of environmental enteropathy, with careful studies of the effect on growth rate and protein status.
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Affiliation(s)
- Nirupama Shivakumar
- Division of Nutrition, St. John's Research Institute, St. John's National Academy of Health Sciences, Bangalore, Karnataka, India
| | - Paul Kelly
- Tropical Gastroenterology and Nutrition Group, University of Zambia School of Medicine, Lusaka, Zambia
- Blizard Institute, Faculty of Medicine, Queen Mary University of London, London, UK
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Brouwer AF, Lee GO, Schillinger RJ, Edwards CA, Van Wyk H, Yazbeck R, Morrison DJ. Mechanistic inference of the metabolic rates underlying [Formula: see text]C breath test curves. J Pharmacokinet Pharmacodyn 2023; 50:203-214. [PMID: 36790613 PMCID: PMC10544773 DOI: 10.1007/s10928-023-09847-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Accepted: 02/01/2023] [Indexed: 02/16/2023]
Abstract
Carbon stable isotope breath tests offer new opportunities to better understand gastrointestinal function in health and disease. However, it is often not clear how to isolate information about a gastrointestinal or metabolic process of interest from a breath test curve, and it is generally unknown how well summary statistics from empirical curve fitting correlate with underlying biological rates. We developed a framework that can be used to make mechanistic inference about the metabolic rates underlying a 13C breath test curve, and we applied it to a pilot study of 13C-sucrose breath test in 20 healthy adults. Starting from a standard conceptual model of sucrose metabolism, we determined the structural and practical identifiability of the model, using algebra and profile likelihoods, respectively, and we used these results to develop a reduced, identifiable model as a function of a gamma-distributed process; a slower, rate-limiting process; and a scaling term related to the fraction of the substrate that is exhaled as opposed to sequestered or excreted through urine. We demonstrated how the identifiable model parameters impacted curve dynamics and how these parameters correlated with commonly used breath test summary measures. Our work develops a better understanding of how the underlying biological processes impact different aspect of 13C breath test curves, enhancing the clinical and research potential of these 13C breath tests.
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Affiliation(s)
- Andrew F. Brouwer
- Department of Epidemiology, University of Michigan, 1415 Washington Heights, Ann Arbor, 48109, MI, United States
| | - Gwenyth O. Lee
- Department of Epidemiology, University of Michigan, 1415 Washington Heights, Ann Arbor, 48109, MI, United States
| | - Robert J. Schillinger
- Scottish Universities Environmental Research Centre, University of Glasgow, Rankine Avenue, East Kilbride, G75 0QF, United Kingdom
- School of Medicine, Dentistry and Nursing, University of Glasgow, University Ave, Glasgow, G12 8QQ, United Kingdom
| | - Christine A. Edwards
- School of Medicine, Dentistry and Nursing, University of Glasgow, University Ave, Glasgow, G12 8QQ, United Kingdom
| | - Hannah Van Wyk
- Department of Epidemiology, University of Michigan, 1415 Washington Heights, Ann Arbor, 48109, MI, United States
| | - Roger Yazbeck
- College of Medicine and Public Health, Flinders University, University Ave, Adelaide, 5001, South Australia
| | - Douglas J. Morrison
- Scottish Universities Environmental Research Centre, University of Glasgow, Rankine Avenue, East Kilbride, G75 0QF, United Kingdom
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Shivakumar N, Kashyap S, Jahoor F, Devi S, Preston T, Thomas T, Kurpad AV. The systemic availability of indispensable amino acids from orally ingested algal and legume protein in young children at risk of environmental enteric dysfunction. Am J Clin Nutr 2023:S0002-9165(23)48907-1. [PMID: 37178715 DOI: 10.1016/j.ajcnut.2023.05.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 05/02/2023] [Accepted: 05/04/2023] [Indexed: 05/15/2023] Open
Abstract
BACKGROUND The digestion and absorption of ingested protein may be reduced in children with environmental enteric dysfunction (EED), reducing systemic amino acid availability for protein synthesis with resultant growth faltering. This has not been directly measured in children with EED and associated growth faltering. OBJECTIVE To evaluate the systemic availability of algal (spirulina) and legume (mung bean) IAA in children with EED. METHODS Indian children (18-24 months) from urban slums were assigned to EED (n=24) or no-EED (control, n=17) groups based on the lactulose rhamnose test, where the lactulose rhamnose ratio (LRR) cut-off for diagnosing EED (≥0.068) was the mean + 2SD of its distribution in healthy, age- and sex-matched children of high socio-economic status. Fecal biomarkers of EED were also measured. Systemic IAA availability was calculated from the plasma:meal IAA enrichment ratio for each protein. True ileal mung bean IAA digestibility was measured by the dual isotope tracer method using spirulina protein as reference. Co-administration of free 13C6-phenylalanine allowed for estimating true ileal phenylalanine digestibility from both proteins, and a phenylalanine absorption index. RESULTS There was no significant difference (independent t-test) in the systemic IAA availability from spirulina or mung bean protein between EED and no-EED groups. There was no between-group difference in true ileal phenylalanine digestibility and its absorption index, or in mung bean IAA digestibility. CONCLUSION The systemic IAA availability of algal and legume protein, or the latter's IAA/phenylalanine digestibility, are not significantly reduced in children with EED and did not correlate with linear growth.
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Affiliation(s)
- Nirupama Shivakumar
- Division of Nutrition, St. John's Research Institute, St. John's National Academy of Health Sciences, Bangalore, India
| | - Sindhu Kashyap
- Division of Nutrition, St. John's Research Institute, St. John's National Academy of Health Sciences, Bangalore, India
| | - Farook Jahoor
- USDA/Agricultural Research Service, Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA
| | - Sarita Devi
- Division of Nutrition, St. John's Research Institute, St. John's National Academy of Health Sciences, Bangalore, India
| | - Thomas Preston
- Scottish Universities Environmental Research Centre, East Kilbride, Scotland, United Kingdom
| | - Tinku Thomas
- Department of Biostatistics, St. John's Medical College, St. John's National Academy of Health Sciences, Bangalore, India
| | - Anura V Kurpad
- Department of Physiology, St. John's Medical College, St. John's National Academy of Health Sciences, Bangalore, India.
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Sinha S, Loechl CU. Atoms for Nutrition: IAEA's Contribution to Tackling Malnutrition. J Nutr 2023; 153:10-16. [PMID: 36913443 DOI: 10.1016/j.tjnut.2022.11.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 11/03/2022] [Accepted: 11/11/2022] [Indexed: 12/24/2022] Open
Abstract
Nuclear techniques, including stable isotope techniques, provide great potential for understanding nutrition and human health with better accuracy and precision compared with other routine techniques. The International Atomic Energy Agency (IAEA) has been at the forefront for more than 25 y to offer guidance and support on the use of nuclear techniques. This article demonstrates how the IAEA has enabled its Member States to contribute to good health and well-being in their countries and to assess progress toward achieving global nutrition and health targets to combat malnutrition in all its forms. Support is provided in several ways including research, capacity building, education, and training as well as the provision of guidance materials. The nuclear techniques help to objectively measure nutritional and health-related outcomes such as body composition, energy expenditure, nutrient uptake, and body stores and assess breastfeeding practices as well as environmental interactions. These techniques are continuously improved to make nutritional assessments more affordable and less invasive with wide use in field settings. New research areas are emerging to assess diet quality with changing food systems and to explore stable isotope-assisted metabolomics to address key questions on nutrient metabolism. Through a deeper understanding of mechanisms, nuclear techniques can contribute to eradicating malnutrition worldwide.
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Affiliation(s)
- Srishti Sinha
- Nutritional and Health-Related Environmental Studies Section, Division of Human Health, International Atomic Energy Agency, Vienna, Austria
| | - Cornelia U Loechl
- Nutritional and Health-Related Environmental Studies Section, Division of Human Health, International Atomic Energy Agency, Vienna, Austria.
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