Luc J C van Loon

Maastricht University | UM · M3-research unit at the Department of Human Biology & Movement Sciences School of Nutrition and Translational Research in Metabolism Faculty of Health, Medicine and Life Sciences

Background & aims: Hemodialysis removes amino acids from the circulation, thereby stimulating muscle proteolysis. Protein ingestion during hemodialysis can compensate for amino acid removal but may also increase uremic toxin production. Branched-chain ketoacid (BCKA) co-ingestion may provide an additional anabolic stimulus without adding to uremic...

Dietary protein digestion and amino acid absorption rates are modulated by numerous factors such as the food matrix. It has been speculated that protein ingested in liquid form is more rapidly digested and absorbed when compared with ingestion in solid form. Here, we assessed the postprandial plasma amino acid availability following ingestion of a...

Skeletal muscle disuse reduces muscle protein synthesis rates and induces atrophy, events associated with decreased mitochondrial respiration and increased reactive oxygen species. Given that dietary nitrate can improve mitochondrial bioenergetics, we examined whether nitrate supplementation attenuates disuse‐induced impairments in mitochondrial fu...

Introduction: Protein ingestion during recovery from exercise has been reported to augment myofibrillar protein synthesis rates, without increasing muscle connective protein synthesis rates. It has been suggested that collagen protein may be effective in stimulating muscle connective protein synthesis. The present study assessed the capacity of bo...

Context: Androgen deprivation therapy (ADT) forms the cornerstone in prostate cancer (PCa) treatment. ADT however also lowers skeletal muscle mass. Objective: To identify the impact of ADT with and without resistance exercise training on muscle fiber characteristics in PCa patients. Methods: Twenty-one PCa patients (72 ± 6 y) starting ADT were...

Background: Myotonic dystrophy type 1 (DM1) patients are at risk for metabolic abnormalities and commonly experience overweight and obesity. Possibly, weight issues result from lowered resting energy expenditure (EE) and impaired muscle oxidative metabolism. Objectives: This study aims to assess EE, body composition, and muscle oxidative capacit...

Acute ketone monoester (KE) supplementation can alter exercise responses, but the performance effect is unclear. The limited and equivocal data to date are likely related to factors including the KE dose, test conditions, and caliber of athletes studied. We tested the hypothesis that mean power output during a 20-min cycling time trial (TT) would b...

Background: A key hallmark of aging is the progressive loss of skeletal muscle mass. Due to limitations of the various methods typically applied to assess muscle mass, only limited information is available on age-related differences between various muscle groups. This study assessed differences in individual lower body muscle group volumes between...

Background Casein protein ingestion prior to sleep has been shown to increase myofibrillar protein synthesis rates during overnight sleep. It remains to be assessed whether pre-sleep protein ingestion can also increase mitochondrial protein synthesis rates. Though it has been suggested that casein protein may be preferred as a pre-sleep protein sou...

Impaired heart function can develop in individuals with diabetes in the absence of coronary artery disease or hypertension, suggesting mechanisms beyond hypertension/increased afterload contribute to diabetic cardiomyopathy. Identifying therapeutic approaches that improve glycemia and prevent cardiovascular disease are clearly required for clinical...

Introduction: We assessed whether collagen supplementation augments the effects of high-impact exercise on bone turnover and whether a higher exercise frequency results in a greater benefit for bone metabolism. Methods: In this randomized, cross-over trial, 14 healthy males (age 24 ± 4 y, BMI 22.0 ± 2.1 kg/m2) performed 5-min of high-impact exer...

Purpose: To assess the prevalence of low bone mineral density (BMD) in male and female elite cyclists at different stages of a professional cycling career, and to identify potential risk factors of low BMD. Methods: In this cross-sectional study, 93 male and female early career, advanced career, and post-career elite cyclists completed dual-ener...

Objectives To assess the adverse impact of the first 5 months of androgen deprivation therapy on body composition, physical performance, cardiometabolic health and health-related quality-of-life in prostate cancer patients. Materials and Methods Thirty-four prostate cancer patients (70 ± 7 years) were assessed shortly after initiation of androgen...

Background: Muscle mass and strength decrease during short periods of immobilization and slowly recover during remobilization. Recent artificial intelligence applications have identified peptides that appear to possess anabolic properties in in vitro assays and murine models. Objectives: This study aimed to compare the impact of Vicia faba pepti...

Background: Ageing of skeletal muscle is characterized in some by muscle fiber type grouping due to denervation-reinnervation cycles, but the severity of fiber type grouping varies widely across individuals of the same chronological age. It remains unknown whether fiber type grouping is associated with lower muscle mass and/or reduced physical func...

Patients infected with SARS-CoV-2 who have been admitted to the intensive care unit (ICU) often face months of physical disability after discharge. To optimize recovery, it is important to understand the role of musculoskeletal alterations in critically ill patients infected with SARS-CoV-2. The main aim of the present study was to describe the pre...

Purpose: To assess the effects of 20 weeks resistance exercise training with or without protein supplementation on body composition, muscle mass, muscle strength, physical performance and aerobic capacity in prostate cancer patients receiving androgen deprivation therapy (ADT). Methods: Sixty prostate cancer patients receiving ADT were randomly...

Skeletal muscle is maintained and repaired by sub‐laminar, Pax7‐expressing satellite cells. However, recent mouse investigations have described a second myogenic progenitor population that resides within the myofiber interstitium and expresses the transcription factor Twist2. Twist2‐expressing cells exclusively repair and maintain type IIx/b muscle...

Objective This study aimed to assess the impact of time-restricted eating (TRE) on integrated skeletal muscle myofibrillar protein synthesis (MyoPS) rates in males with overweight/obesity. Methods A total of 18 healthy males (age 46 ± 5 years; BMI: 30 ± 2 kg/m²) completed this exploratory, parallel, randomized dietary intervention after a 3-day le...

Background: Ingestion of protein concentrates or isolates increases muscle protein synthesis rates in young and older adults. There is far less information available on the anabolic response following the ingestion of dairy wholefoods, which are commonly consumed in a normal diet. Objectives: This study investigates whether ingestion of 30 g pro...

Purpose To determine the effects of dietary sugar or carbohydrate restriction on physical activity energy expenditure, energy intake, and physiological outcomes across 24 h. Methods In a randomized, open-label crossover design, twenty-five healthy men ( n = 10) and women ( n = 15) consumed three diets over a 24-h period: moderate carbohydrate and...

Background: Plant-derived proteins are considered to have lesser anabolic properties when compared with animal-derived proteins. The attenuated rise in muscle protein synthesis rates following ingestion of plant-derived compared with animal-derived protein has been, at least partly, attributed to deficiencies in specific amino acids such as leucine...

Dietary interventions to delay carbohydrate digestion or absorption can effectively prevent hyperglycemia in the early postprandial phase. L-arabinose can specifically inhibit sucrase. It remains to be assessed whether co-ingestion of L-arabinose with sucrose delays sucrose digestion, attenuates subsequent glucose absorption, and impacts hepatic gl...

Background Egg protein is ingested during recovery from exercise to facilitate the post-exercise increase in muscle protein synthesis rates and, as such, to support the skeletal muscle adaptive response to exercise training. The impact of cooking egg protein on post-exercise muscle protein synthesis is unknown. Objectives To compare the impact of...

Objective Dietary protein and physical activity interventions are increasingly implemented during hemodialysis to support muscle maintenance in patients with end-stage renal disease. Though muscle maintenance is important, adequate removal of uremic toxins throughout hemodialysis is the primary concern for patients. It remains to be established whe...

Abstract: Many critically ill patients infected with SARS-CoV-2 have been submitted to an intensive care unit (ICU). Patients with a SARS-CoV-2 infection that survive critical illness are confronted with months of physical impairments. To maximize recovery, it is important to understand the musculoskeletal involvement in critically ill patients inf...

Background. Lumbar disc herniation (LDH) is the most common diagnosed degenerative pathology in the lumbar spine. Because of its role in spinal stability there is an increased interest in the role of the Lumbar Multifidus muscle in low back painresearch. Despite surgical treatment long-term, disability and pain remain a persistent problem. The aim...

Rapid oscillations in cytosolic calcium (Ca ²⁺ ) coordinate muscle contraction, relaxation, and physical movement. Intriguingly, dietary nitrate decreases ATP cost of contraction, increases force production, and increases cytosolic Ca ²⁺ ; which would seemingly necessitate a greater demand for sarcoplasmic reticulum Ca ²⁺ ATPase (SERCA) to sequeste...

Objectives To determine the effects of dietary sugar or carbohydrate restriction on physical activity energy expenditure, energy intake, and physiological outcomes across 24 hours. Methods In a randomised, open-label crossover design, twenty-five healthy men (n = 10) and women (n = 15) consumed three diets over a 24-hour period: moderate carbohydr...

PURPOSE: Establish the time-course of changes in oxygen consumption, substrate metabolism, and heart rate during treadmill walking upon commencing a low-carbohydrate, ketogenic diet. METHODS: In a randomized, parallel group design, 53 healthy men and women (mean±SD, age: 35±16 years, body mass index: 24±3 kg/m2) were allocated to either a moderate...

Maintaining good glycemic control to prevent complications is crucial in people with type 2 diabetes and in people with prediabetes and in the general population. Different strategies to improve glycemic control involve the prescription of blood glucose‐lowering drugs and the modulation of physical activity and diet. Interestingly, lifestyle interv...

Rationale Dietary protein may attenuate the muscle atrophy experienced by patients in the Intensive Care Unit (ICU), yet protein handling is poorly understood. Objective To quantify protein digestion and amino acid absorption, and fasting and postprandial myofibrillar protein synthesis during critical illness. Methods Fifteen mechanically ventilate...

Cachexia is a prevalent muscle wasting syndrome among people with advanced cancer that profoundly impacts patient quality of life (QoL) and physical function. Exercise can improve QoL, physical function, and overall health in people with cancer and may be an important addition to treatment approaches for cancer cachexia. Greater understanding of pa...

The molecular responses to acute resistance exercise are well characterized. However, how cellular signals change over time to modulate chronic adaptations to more prolonged exercise training is less well understood. We investigated anabolic signaling and muscle protein synthesis rates at several time points after acute and chronic eccentric loadin...

Collagen is the central structural component of extracellular connective tissue, which provides elastic qualities to tissues. For skeletal muscle, extracellular connective tissue transmits contractile force to the tendons and bones. Connective tissue proteins are in a constant state of remodeling and have been shown to express a high level of plast...

Introduction Plant-derived proteins have received considerable attention as an alternative to animal-based proteins and are now frequently used in both plant-based diets and sports nutrition products. However, little information is available on the anabolic properties of potato-derived protein. This study compares muscle protein synthesis rates aft...

Addressing skeletal muscle mass loss is an important focus in oncology research to improve clinical outcomes, including cancer treatment tolerability and survival. Exercise is likely a necessary component of muscle-mass-preserving interventions for people with cancer. However, randomized controlled trials with exercise that include people with canc...

Background Handheld dynamometry (HHD) is a practical alternative to traditional testing of lower extremity strength. However, its reliability and validity across different populations and settings are not clear. Hypothesis We hypothesize that HHD is a valid and reliable device to assess lower extremity strength in a population of older adults. St...

Consumers are increasingly encouraged to consume more plant-based foods and lower their consumption of foods from animal origin. Concurrently, older adults are recommended to consume an adequate amount of high-quality dietary protein for the prevention of age-related muscle loss. In the current perspective, we discuss why it may not be preferred to...

Background: The rate of protein digestion and amino acid absorption determines the postprandial rise in circulating amino acids and modulates postprandial muscle protein synthesis rates. Objective: We sought to compare protein digestion, amino acid absorption kinetics, and the postprandial muscle protein synthetic response following ingestion of...

Background Protein ingestion increases muscle protein synthesis rates. The food matrix in which protein is provided can strongly modulate the postprandial muscle protein synthetic response. So far, the muscle protein synthetic response to the ingestion of whole foods remains largely unexplored. Objectives To compare the impact of ingesting 30g pro...

Background Magnesium plays a key role in bone health and may, therefore, represent an interesting nutrient for the prevention of bone loss and osteoporosis. The aim of this systematic review and meta-analysis was to investigate the impact of magnesium intake from any source on bone mineral density (BMD), bone mineral content (BMC), bone turnover ma...

Plant-based proteins are considered to be less effective in their capacity to stimulate muscle protein synthesis when compared with animal-based protein sources, likely due to differences in amino acid contents. We compared the postprandial muscle protein synthetic response following the ingestion of a lysine-enriched plant-based protein product wi...

A correction to this paper has been published: https://doi.org/10.1007/s40279-021-01489-8

Background Metabolic reprogramming is a common phenomenon in tumorigenesis and tumor progression. Amino acids are important mediators in cancer metabolism, and their kinetics in tumor tissue are far from being understood completely. Mass spectrometry imaging is capable to spatiotemporally trace important endogenous metabolites in biological tissue...

Purpose of Review Osteoarthritis (OA) is the most common forms of arthritis in the general population, accounting for more pain and functional disability than any other musculoskeletal disease. There are currently no approved disease modifying drugs for OA. In the absence of effective pharmacotherapy, many patients with OA turn to nutritional suppl...

Individuals with hepatic steatosis often display several metabolic abnormalities including insulin resistance and muscle atrophy. Previously, we found that hepatic steatosis results in an altered hepatokine secretion profile, thereby inducing skeletal muscle insulin resistance via inter-organ crosstalk. In this study, we aimed to investigate whethe...

Background Patients with end-stage renal disease (ESRD) undergoing hemodialysis experience a rapid decline in skeletal muscle mass and strength. Hemodialysis removes amino acids (AAs) from the circulation, thereby lowering plasma AA concentrations and stimulating proteolysis. Objectives In the present study, we evaluate the impact of intradialytic...

There is a global trend of an increased interest in plant-based diets. This includes an increase in the consumption of plant-based proteins at the expense of animal-based proteins. Plant-derived proteins are now also frequently applied in sports nutrition. So far, we have learned that the ingestion of plant-derived proteins, such as soy and wheat p...

PURPOSE: Hemodialysis (HD) is a life-saving treatment for end-stage renal disease (ESRD) patients. However, it removes amino acids (AAs) from the circulation, thereby lowering plasma AA concentrations and stimulating muscle catabolism. To prevent deterioration in the nutritional status of HD patients, protein ingestion and exercise during HD are in...

Previous studies have used supplements to increase dietary nitrate intake in clinical populations. Little is known about whether effects can also be induced through vegetable consumption. Therefore, the aim of this study was to assess the impact of dietary nitrate, through nitrate-rich vegetables (NRV) and beetroot juice (BRJ) supplementation, on p...

Skeletal muscle mass losses with age are associated with negative health consequences, including an increased risk of developing metabolic disease and the loss of independence. Athletes adopt numerous nutritional strategies to maximize the benefits of exercise training and enhance recovery in pursuit of improving skeletal muscle quality, mass, or f...

Purpose: Dietary nitrate has been shown to enhance muscle contractile function and has, therefore, been linked to increased muscle power and sprint exercise performance. However, the impact of dietary nitrate supplementation on maximal strength, performance and muscular endurance remains to be established. Methods: Fifteen recreationally active mal...

Objectives It has been reported that plant-based proteins are not as effective as animal-based proteins in their capacity to stimulate muscle protein synthesis rates. This has been attributed to the lower essential amino acid content and the selective deficiency in specific amino acids. It has been hypothesized that a blend of different plant-based...

Background Emerging evidence suggests that increasing dietary nitrate intake may be an effective approach to improve cardiovascular health. However, the effects of a prolonged elevation of nitrate intake through an increase in vegetable consumption are understudied. Objective Our primary aim was to determine the impact of 12 wk of increased daily...

Background: Insects have recently been identified as a more sustainable protein-dense food source and may represent a viable alternative to conventional animal-derived proteins. Objectives: We aimed to compare the impacts of ingesting lesser mealworm- and milk-derived protein on protein digestion and amino acid absorption kinetics, postprandial...

Background: In vivo muscle protein synthesis rates are typically assessed by measuring the incorporation rate of stable isotope labelled amino acids in skeletal muscle tissue collected from vastus lateralis muscle. It remains to be established whether muscle protein synthesis rates in the vastus lateralis are representative of muscle protein synth...

Protein ingestion and exercise stimulate myofibrillar protein synthesis rates. When combined, exercise further increases the postprandial rise in myofibrillar protein synthesis rates. It remains unclear whether protein ingestion with or without exercise also stimulates muscle connective tissue protein synthesis rates. The authors assessed the impac...