Nicolaas Deutz

• MD, PhD
• Managing Director at Texas A&M University

Inadequate sleep has been associated with an increased risk of mortality and various health issues. We previously conducted a placebo-controlled vaccination trial of healthy adults who were monitored by blood samples, questionnaires, and wearable devices. C-reactive protein (CRP), a systemic marker of inflammation, has been linked to numerous healt...

Duchenne muscular dystrophy (DMD) is a severe neuromuscular disease due to loss of dystrophin, leading to progressive muscle wasting and physical inactivity. In this pilot study, we studied the effect of daily supplementation of the anabolic substrate beta-hydroxy-beta-methylbutyrate (HMB) on whole body protein and amino acid kinetics using novel i...

Sarcopenia and hepatic encephalopathy (HE) are complications of chronic liver disease (CLD), which negatively impact clinical outcomes. Hyperammonemia is considered to be the central component in the pathogenesis of HE, however ammonia’s toxic effects have also been shown to impinge on extracerebral organs including the muscle. Our aim was to inves...

Sepsis leads to an acute breakdown of muscle to support increased caloric and amino acid requirements. Little is known about the role of adipose and muscle tissue breakdown and intestinal metabolism in glucose substrate supply during the acute phase of sepsis. In a translational porcine model of sepsis, we explored the across organ net fluxes of gl...

Inadequate sleep has been associated with an increased risk of mortality and various health issues, but the role of sleep metrics from wearables in public health remains unclear. C-reactive protein (CRP), a systemic marker of inflammation, has been linked to numerous health outcomes. We hypothesized that sleep duration is associated with an inflamm...

Background Continuous glucose monitoring (CGM) systems allow detailed assessment of postprandial glucose responses (PPGR), offering new insights into food choices’ impact on dysglycemia. However, current approaches to analyze PPGR using a CGM require manual meal logging, limiting the scalability of CGM-driven applications like personalized nutritio...

Human sepsis is characterized by increased protein breakdown and changes in arginine and citrulline metabolism. However, it is unclear whether this is caused by changes in transorgan metabolism. We therefore studied in a Pseudomonas aeruginosa induced pig sepsis model the changes in protein and arginine related metabolism on whole body (Wb) and tra...

Microbe-produced molecules (xenometabolites) found in foods or produced by gut microbiota are increasingly implicated in microbe-microbe and microbe-host communication. Xenolipids, in particular, are a class of metabolites for which the full catalog remains to be elaborated in mammalian systems. We and others have observed that cis-3,4-methylene-he...

Purpose Patients with cancer often experience nutritional challenges and are vulnerable to muscle mass loss. While substantial research is directed towards understanding how nutritional interventions affect clinical outcomes, insights into patients’ personal experiences during these trials remain limited. This qualitative study aimed to gain a deep...

The metachromatic dye dimethylmethylene blue is used to quantify total glycosaminoglycans in urine. Understanding the interaction of dimethylmethylene blue with glycosaminoglycans is pertinent to optimize the assay procedure depending on the type of sample and interpret the findings meaningfully. The present spectrophotometric study determined the...

Purpose of review Stable isotope methods have been used for many years to assess whole body protein and amino acid kinetics in critically ill patients. In recent years, new isotope approaches and tracer insights have been developed. The tracer pulse approach has some advantages above the established primed-continuous tracer infusion approach becaus...

Background & aims: Sex differences in muscle function and mass, dyspnea, and clinical outcomes have been observed in patients with Chronic Obstructive Pulmonary Disease (COPD) despite a similar level of airflow obstruction. Protein and amino acid metabolism is altered in COPD, however, it remains unclear whether a difference in metabolic signature...

Background: This narrative review describes foundational and emerging evidence of how dietary protein intakes may influence muscle-related attributes of older adults. Methods: PubMed was used to identify pertinent research. Results: Among medically stable older adults, protein intakes below the recommended dietary allowance (RDA) (0.8 g/kg bod...

Abnormalities pertaining to glycoconjugates (glycoproteins, proteoglycans, and glycolipids) of the neural extracellular matrix have been identified as a susceptibility factor in autism spectrum disorder. We studied the urine excretion of sulfated glycosaminoglycans in children with autism spectrum disorder (n=61), in comparison to age- and sex-matc...

To better understand working memory (WM) deficits in Mild Cognitive Impairment (MCI), we examined information precision and associative binding in WM in 21 participants with MCI, compared to 16 healthy controls, using an item-location delayed reproduction task. WM, along with other executive functions (i.e. Trail Making Task (TMT) and Stroop task),...

Children with autism spectrum disorder may exhibit nutritional deficiencies due to reduced intake, genetic variants, autoantibodies interfering with vitamin transport, and the accumulation of toxic compounds that consume vitamins. Importantly, vitamins and metal ions are essential for several metabolic pathways and for neurotransmitter functioning....

Background: The trajectory from healthy to critical illness is influenced by numerous factors, including metabolism, which differs substantially between males and females. Whole body protein breakdown is substantially increased in critically ill patients, but it remains unclear whether there are sex differences that could explain the different hea...

Background: Production rates of the short-chain fatty acids (SCFA) acetate, propionate, and butyrate, which are beneficial metabolites of the intestinal microbiota, are difficult to measure in humans due to inaccessibility of the intestine to perform measurements, and the high first-pass metabolism of SCFAs in colonocytes and liver. We developed a...

Background Abdominal obesity (AO) is linked to reduced health status and mortality. While it is known that AO is prevalent in chronic obstructive pulmonary disease (AO-COPD), the specific metabolic and functional consequences associated with AO-COPD remain understudied. Methods We studied 199 older adults with COPD and 168 control subjects with an...

Background β−hydroxy-β−methylbutyrate (HMB) might improve muscle function and maintain its mass in critically ill patients. We aimed to investigate whether the administration of HMB influenced the plasma levels of growth hormone (GH)/insulin-like growth factor-1 (IGF-1), C-peptide, and 25-OH vitamin-D. Methods Post-hoc analysis of the study HMB-IC...

In 1982 and 2011, Clinical Science published papers that used infusion of stable isotope-labeled amino acids to assess skeletal muscle protein synthesis in the fasted and fed state and before and after a period of increased intake of omega-3 fatty acids, respectively; both of these papers have been highly cited. An overview of the study designs, ke...

Background There is growing interest in the supplementation of arginine (Arg) and citrulline (Cit) in obesity due to their potential anti-obesogenic and anti-inflammatory properties. However, there is no consensus on the metabolic changes in Arg kinetics in obesity. Objective This exploratory cross-sectional study aimed to investigate the associat...

Background & Aims In patients with malnutrition there is an increased long-term risk for mortality beyond the preciding hospital stay. We investigated the effects of postdischarge nutritional support in the outpatient setting on all-cause mortality in the populaton of malnourished medical patients in a systematic review of randomized controlled tri...

Background Dietary changes often accompany management of a cancer diagnosis but how and why patients with colorectal cancer (CRC) make dietary decisions requires further investigation. Objective To learn about patients’ food-related beliefs and understand if and why dietary changes were made by patients starting chemotherapy following a CRC diagno...

With prolonged pandemic conditions, and emerging evidence but persisting low awareness of the importance of nutritional derangements, ESPEN has promoted in close collaboration with World Health Organization-Europe a call for papers on all aspects relating COVID-19 and nutrition as well as nutritional care, in the Society Journals Clinical Nutrition...

Understanding how macronutrients (e.g., carbohydrates, protein, fat) affect blood glucose is of broad interest in health and dietary research. The general effects are well known, e.g., adding protein and fat to a carbohydrate-based meal tend to reduce blood glucose. However, there are large individual differences in food metabolism, to where the sa...

Background There is increasing evidence from randomized controlled trials showing that different types of nutritional support interventions improve clinical outcomes in malnourished medical inpatients. Whether trials using micronutrient supplementation in addition to nutritional therapy are superior to trials without micronutrient supplementation r...

Background There has been growing interest in studying postprandial glucose responses using continuous glucose monitoring (CGM) in non-diabetic individuals. Accurate measurement of glucose responses to meals can facilitate applications such as precision nutrition and early detection of diabetes. Objectives We aimed to quantify the discordance in s...

Sustained high levels of blood glucose in type 2 diabetes (T2DM) can have disastrous long-term health consequences. An essential component of clinical interventions for T2DM is monitoring dietary intake to keep plasma glucose levels within an acceptable range. Yet, current techniques to monitor food intake are time intensive and error prone. To add...

As authors of recent meta-analyses evaluating lipids for parenteral nutrition1,2 and/or the ESPEN Expert Group: lipids in the intensive care unit3 we welcome the updating of the ASPEN guidelines for clinical nutrition in adult critically ill patients,4 but would like to remark on certain aspects that cause us concern This article is protected by c...

Background Disturbances in protein metabolism and impaired muscle health have been observed in chronic obstructive pulmonary disease (COPD). The ω-3 (n–3) PUFAs EPA and DHA are known for their anti-inflammatory and muscle health-enhancing properties. Objectives We examined whether daily EPA + DHA supplementation can improve daily protein homeostas...

Low muscle mass is prevalent among patients with cancer and a predictor of adverse clinical outcomes. To counteract muscle loss, β‐hydroxy β‐methylbutyrate (HMB) supplementation has been proposed as a potential therapy for older adults and various diseases states. This systematic review aimed to investigate the effects and safety of HMB supplementa...

Background & aims Postabsorptive whole body protein kinetics are related to age, gender, body mass index (BMI), and habitual protein intake level. It is unclear how protein synthesis, breakdown, and postabsorptive protein balance rates are affected in Chronic Obstructive Pulmonary Disease (COPD)) and whether these relate to disease severity, lifest...

Purpose of review: The branched-chain amino acids (BCAA), branched-chain keto acids (BCKA), and β-hydroxy β-methylbutyric acid (HMB) have regained interest as food ingredients in health and disease. To support nutritional strategies, it is critical to gain insight into the whole body and transorgan kinetics of these components. We, therefore, revi...

Background: Depression is one of the most common and untreated comorbidities in chronic obstructive pulmonary disease (COPD), and is associated with poor health outcomes (e.g. increased hospitalization/exacerbation rates). Although metabolic disturbances have been suggested in depressed non-diseased conditions, comprehensive metabolic phenotyping...

The short-chain fatty acids (SCFAs) acetate, propionate, butyrate, isovalerate, and valerate are end products of intestinal bacterial fermentation and important mediators in the interplay between the intestine and peripheral organs. To unravel the transorgan fluxes and mass balance comparisons of SCFAs, we measured their net fluxes across several o...

Background There is increasing evidence from randomized-controlled trials demonstrating that nutritional support improves clinical outcomes in the population of malnourished medical inpatients. We investigated associations of trial characteristics including clinical setting, duration of intervention, individualization of nutritional support and amo...

Background The amount of the macronutrients protein and carbohydrate (CHO) in a mixed meal is known to affect each other's digestion, absorption, and subsequent metabolism. While the effect of the amount of dietary protein and fat on the glycemic response is well studied, the ability of postprandial plasma amino acid patterns to predict the meal co...

Purpose Muscle wasting deteriorates life quality after critical illness and increases mortality. Wasting starts upon admission to intensive care unit (ICU). We aimed to determine whether β−hydroxy-β−methylbutyrate (HMB), a metabolite of leucine, can attenuate this process. Methods Prospective randomized, placebo-controlled double blind trial. Incl...

Purpose of review: This review will discuss recent studies showing that patients with chronic wasting diseases suffer from a variety of small intestinal impairments which might negatively impact the colonic microbiota and overall well-being. New insights will be addressed as well as novel approaches to assess intestinal function. Recent findings:...

Objectives Cancer patients were shown to have an altered intestinal microbiota composition and lower fecal concentrations of the bacterial metabolites short-chain fatty acids (SCFA), which among others serve as energy source to muscle. We previously described an association between reduced plasma SCFA concentrations and muscle dysfunction in chroni...

PurposeIn recent years, point-of-care (POC) devices, especially smart wearables, have been introduced to provide a cost-effective, comfortable, and accessible alternative to polysomnography (PSG)—the current gold standard—for the monitoring, screening, and diagnosis of obstructive sleep apnea (OSA). Thorough validation and human subject testing are...

Background: Small and large intestinal perturbations have been described as prevalent extracardiac systemic manifestations in Congestive Heart Failure (CHF) but alterations in protein digestion and absorption and plasma short-chain fatty acid concentrations (SCFA), and the potential link with other systemic effects (e.g. lower muscle and cognitive...

Introduction Reduced skeletal muscle function and cognitive performance are common extrapulmonary features in Chronic Obstructive Pulmonary Disease (COPD) but their connection remains unclear. Whether presence or absence of skeletal muscle dysfunction in COPD patients is linked to a specific phenotype consisting of reduced cognitive performance, co...

Wild game consumption has been associated with health benefits but the acute influence on human protein metabolism remains unknown. We compared feeding-induced responses of equivalent amounts of free-range reindeer (FR) and commercial beef (CB) on protein kinetics using stable isotope methodology. Seven participants (age: 40 ± 14 years; body mass i...

There are multiple lines of evidence for an impaired sulfur amino acid (SAA) metabolism in autism spectrum disorder (ASD). For instance, the concentrations of methionine, cysteine and S-adenosylmethionine (SAM) in body fluids of individuals with ASD is significantly lower while the concentration of S-adenosylhomocysteine (SAH) is significantly high...

Amino acid (AA) metabolism is severely disturbed in critically ill ICU patients. To be able to make a more scientifically based decision of when and in which protein and AA composition to deliver in ICU, comprehensive AA phenotyping with measurements of plasma concentrations and whole body production (WBP) is needed. Therefore, we studied ICU patie...

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Background Severe muscle mass (MM) loss is a defining feature of cancer observed across all types and stages of disease and is an independent predictor of poor clinical outcomes including higher incidences of chemotherapy toxicity and decreased survival. Protein is essential to build MM, yet the optimal amount for preventing or treating muscle loss...

Objective: Branched-chain amino acids (BCAA) and their metabolites the branched-chain keto acids (BCKA) and β-Hydroxy β-methylbutyric acid (HMB) are involved in the regulation of key signaling pathways in the anabolic response to a meal. However, their (inter)organ kinetics remain unclear. Therefore, BCAA (leucine (LEU), valine (VAL), isoleucine (...

Hibernation is a state of extraordinary metabolic plasticity. The pathways of amino acid metabolism as they relate to nitrogen homeostasis in hibernating mammals in vivo are unknown. Here we show, using pulse isotopic tracing, evidence of increased myofibrillar (skeletal muscle) protein breakdown and suppressed whole-body production of metabolites...

With the rise in physical inactivity and its related diseases, it is necessary to understand the mechanisms involved in physical activity regulation. Biological factors regulating physical activity are studied to establish a possible target for improving the physical activity level. However, little is known about the role metabolism plays in physic...

Purpose: Gut symptoms and markers of gut dysfunction have been observed in patients with Chronic Obstructive Pulmonary disease (COPD). It remains unclear whether walking exercise induces disturbances in protein digestion and amino acid absorption and whole body protein kinetics in these subjects due to exercise induced hypoxia. Methods: Sixteen...

The central position of methionine (Met) in protein metabolism indicates the importance of this essential amino acid for growth and maintenance of lean body mass. Therefore, Met might be a tempting candidate for supplementation. However, because Met is also the precursor of homocysteine (Hcy), a deficient intake of B vitamins or excessive intake of...

Background & aims Gastrointestinal symptoms are prevalent extrapulmonary systemic manifestations of Chronic Obstructive Pulmonary Disease (COPD), but have been rarely studied. We dissected the perturbations in intestinal function in human patients with COPD using comprehensive metabolic and physiological approaches. Methods In this observational s...

Background: 90-day mortality and rehospitalizations are important hospital quality metrics. Biomarkers that predict these outcomes among malnourished hospitalized patients could identify those at risk and help direct care plans. Objectives: To identify biomarkers that predict 90-day (primary) and 30-day (secondary) mortality or nonelective rehos...

Background & aims: Oral Nutritional Supplements (ONS) are used to treat malnutrition and improve clinical outcomes in malnourished patients. Poor handgrip strength (HGS) is associated with an increased risk of mortality, disability and other adverse health consequences. This analysis examined the effect of a specialized ONS on HGS and its relation...

Background: Hospitalized, malnourished older adults with chronic obstructive pulmonary disease (COPD) have an elevated risk of readmission and mortality. Objective: Post-hoc, sub-group analysis from the NOURISH study cohort examined the effect of a high-protein oral nutritional supplement (ONS) containing HMB (HP-HMB) in malnourished, hospitaliz...

Our previous studies suggest that physical activity (PA) levels are potentially regulated by endogenous metabolic mechanisms such as the vasodilatory roles of nitric oxide (NO) production via the precursor arginine (ARG) and ARG-related pathways. We assessed ARG metabolism and its precursors [citrulline (CIT), glutamine (GLN), glutamate (GLU), orni...

Xenometabolites from microbial and plant sources are thought to confer beneficial, as well as deleterious, effects on host physiology. Studies determining absorption and tissue uptake of xenometabolites are limited. We utilized a conscious catheterized pig model to evaluate inter-organ flux of annotated known and suspected xenometabolites, derivati...

Aims Gastrointestinal symptoms are common during chemotherapy, but underlying disturbances in gut function and impact on daily life are unclear. This study investigates gut function in a heterogenous group of cancer patients with gastrointestinal symptoms during chemotherapy, and the relation with anabolic response, muscle health, and daily functio...

Background Lean mass (LM) loss during extended bed rest contributes to long term functional decline in older adults. Identifying blood biomarkers that predict a hospitalized individual’s risk of losing LM could allow for timely intervention. Methods LM from 19 healthy subjects (age 60-76 y, 4 males, 15 females), who were confined to 10 days of com...

Wild game consumption has been associated with health benefits, but the immediate influence on protein metabolism remains unknown. In order to address the direct effects on protein kinetics, we compared the feeding‐induced response to free‐range reindeer versus commercial beef using stable isotope methodology in humans. Eight male and female partic...

Background and aims Malnutrition has been recognized as a major risk factor for adverse postoperative outcomes. The ESPEN Symposium on perioperative nutrition was held in Nottingham, UK, on 14-15 October 2018 and the aims of this document were to highlight the scientific basis for the nutritional and metabolic management of surgical patients. Meth...

Reduced balance function has been observed during balance challenging conditions in the chronic obstructive pulmonary disease (COPD) population and is associated with an increased risk of falls. This study aimed to examine postural balance during quiet standing with eyes open and functional balance in a heterogeneous group of COPD and non-COPD (con...

Evidence-based medicine is the art of combining "best external evidence", "clinical judgement" and "patient values" for improved daily clinical decision making and is the ultimate goal in modern medicine. Historically, in the field of medical nutrition, there had been a lack of strong evidence from large and high-quality trials resulting in often w...

Introduction Reduced skeletal muscle function and cognitive performance are common extrapulmonary features in Chronic Obstructive Pulmonary Disease (COPD) but their connection remains unclear. Whether presence or absence of skeletal muscle dysfunction in COPD patients is linked to a specific phenotype consisting of reduced cognitive performance, co...

Background & aims: Metabolic characterization of a well-defined group of patients could be a powerful tool in revealing metabolic signatures to explain limb muscle weakness in chronic diseases. Studies are currently limited in Chronic Obstructive Pulmonary Disease (COPD) to the identification of differential amino acid concentrations but lack comp...

IMPORTANCE Malnutrition affects a considerable proportion of the medical inpatient population. There is uncertainty regarding whether use of nutritional support during hospitalization in these patients positively alters their clinical outcomes. OBJECTIVE To assess the association of nutritional support with clinical outcomes in medical inpatients w...

Sepsis is a multiorgan disease affecting the ileum and jejunum (small intestine), liver, skeletal muscle, and lung clinically. The specific metabolic changes in the ileum, jejunum, liver, skeletal muscle, and lung have not previously been investigated. Live Pseudomonas aeruginosa, isolated from a patient, was given via i.v. catheter to pigs to indu...

Background & aims: Sepsis is hypothesized as an arginine deficient state, with lack of nitric oxide (NO) for adequate microcirculation and local perfusion. This study aimed to investigate if prolonged (72-h) intravenous l-arginine administration in sepsis patients improves microcirculation. Secondly, effects on arginine and protein metabolism, and...

Introduction Survivors of critical illness often experience significant morbidities, including muscle weakness and impairments in physical functioning. This muscle weakness is associated with longer duration mechanical ventilation, greater hospital costs and increased postdischarge impairments in physical function, quality of life and survival. Com...

Purpose of review: Stable isotope methods have been used for many years to assess whole-body protein and amino acid kinetics in healthy conditions and in response to aging, exercise and (clinically stable) disease states. Recent findings: In recent years, tracer research expanded to the anabolic response to feeding in critical illness and its us...

Objectives Gastrointestinal symptoms are prevalent extracardiac systemic manifestations of Congestive Heart Failure (CHF). We developed a comprehensive panel of methods to unravel gut dysfunction in CHF and its impact on the anabolic response to feeding. Methods We recruited 14 clinically stable CHF patients (ejection fraction: 33.9 ± 2.1, NYHA cl...