Fructose Metabolism and Exercise: Physiological Applications and Limitations

Fructose has gained renewed interest for its suspected role in cardiometabolic diseases and as a performance enhancer in sports nutrition. Both are related to fructose metabolism in the liver resulting in no plasma glucose or insulin peaks, but causing postprandial hyperlactatemia and hypertriglyceridemia. The general aim of this work was to further investigate fructose metabolism and to find potential new applications of fructose that may improve performance. In a first experimental study, we evaluated how fructose metabolism is modulated by an exercise session performed before or after fructose ingestion. Although confirming that fructose is extensively oxidized during exercise, our results also showed that fructose metabolism was largely unaltered when ingested during recovery. In a second study, we used fructose in mixed-meals provided for 24 h postexercise to specifically favor muscle energy storage and subsequent exercise performance. Compared to an isocaloric control, fructose did however not further improve muscle recovery, and fructose impaired whole-body glycogen storage and subsequent exercise performance. In a third study, we investigated the effects of glucose-fructose ingestion during training sessions on lactate metabolism, at rest and during exercise, pre-training and post-training. Interestingly, training with glucose-fructose increased lactate production, consumption and oxidation at rest but not during exercise, and an important part of lactate was directed to non-oxidative fates in all conditions. Altogether, the present results indicate an ambivalent role of fructose, efficient to fuel muscle work, but inefficient during postexercise recovery. This may be largely due to fructose conversion into lactate, furnishing an alternative fuel during exercise that however needs to be stored for an extra energy cost in resting times. In turn, this “reverse Cori cycle” may represent an important mechanism by which fructose effects are matched to physical activity

Metabolic and hormonal response to intermittent high-intensity and continuous moderate intensity exercise in individuals with type 1 diabetes: a randomised crossover study.

AIMS/HYPOTHESIS To investigate exercise-related fuel metabolism in intermittent high-intensity (IHE) and continuous moderate intensity (CONT) exercise in individuals with type 1 diabetes mellitus. METHODS In a prospective randomised open-label cross-over trial twelve male individuals with well-controlled type 1 diabetes underwent a 90 min iso-energetic cycling session at 50% maximal oxygen consumption ([Formula: see text]), with (IHE) or without (CONT) interspersed 10 s sprints every 10 min without insulin adaptation. Euglycaemia was maintained using oral (13)C-labelled glucose. (13)C Magnetic resonance spectroscopy (MRS) served to quantify hepatocellular and intramyocellular glycogen. Measurements of glucose kinetics (stable isotopes), hormones and metabolites complemented the investigation. RESULTS Glucose and insulin levels were comparable between interventions. Exogenous glucose requirements during the last 30 min of exercise were significantly lower in IHE (p = 0.02). Hepatic glucose output did not differ significantly between interventions, but glucose disposal was significantly lower in IHE (p < 0.05). There was no significant difference in glycogen consumption. Growth hormone, catecholamine and lactate levels were significantly higher in IHE (p < 0.05). CONCLUSIONS/INTERPRETATION IHE in individuals with type 1 diabetes without insulin adaptation reduced exogenous glucose requirements compared with CONT. The difference was not related to increased hepatic glucose output, nor to enhanced muscle glycogen utilisation, but to decreased glucose uptake. The lower glucose disposal in IHE implies a shift towards consumption of alternative substrates. These findings indicate a high flexibility of exercise-related fuel metabolism in type 1 diabetes, and point towards a novel and potentially beneficial role of IHE in these individuals. TRIAL REGISTRATION ClinicalTrials.gov NCT02068638 FUNDING: Swiss National Science Foundation (grant number 320030_149321/) and R&A Scherbarth Foundation (Switzerland)

Changes in bone marrow lesions in response to weight-loss in obese knee osteoarthritis patients: a prospective cohort study

BACKGROUND: Patients are susceptible for knee osteoarthritis (KOA) with increasing age and obesity and KOA is expected to become a major disabling disease in the future. An important feature of KOA on magnetic resonance imaging (MRI) is changes in the subchondral bone, bone marrow lesions (BMLs), which are related to the future degeneration of the knee joint as well as prevalent clinical symptoms. The aim of this study was to investigate the changes in BMLs after a 16-week weight-loss period in obese subjects with KOA and relate changes in BMLs to the effects of weight-loss on clinical symptoms. METHODS: This prospective cohort study included patients with a body mass index ≥ 30 kg/m(2), an age ≥ 50 years and primary KOA. Patients underwent a 16 weeks supervised diet program which included formula products and dietetic counselling (ClinicalTrials.gov: NCT00655941). BMLs in tibia and femur were assessed on MRI before and after the weight-loss using the Boston-Leeds Osteoarthritis Knee Score. Response to weight-loss in BML scores was dichotomised to patients experiencing a decrease in BML scores (responders) and patients who did not (non-responders). The association of BMLs to weight-loss was assessed by logistic regressions and correlation analyses. RESULTS: 39 patients (23%) were classified as responders in the sum of all BML size scores whereas 130 patients (77%) deteriorated or remained stable and were categorized as non-responders. Logistic regression analyses revealed no association between weight-loss < or ≥ 10% and response in BMLs in the most affected compartment (OR 1.86 [CI 0.66 to 5.26, p=0.24]). There was no association between weight-loss and response in maximum BML score (OR 1.13 [CI 0.39 to 3.28, p=0.81]). The relationship between changes in BMLs and clinical symptoms revealed that an equal proportion of patients classified as BML responders and non-responders experienced an OMERACT-OARSI response (69 vs. 71%, p=0.86). CONCLUSIONS: Weight-loss did not improve the sum of tibiofemoral BML size scores or the maximum tibiofemoral BML score, suggesting that BMLs do not respond to a rapidly decreased body weight. The missing relationship between clinical symptoms and BMLs calls for further investigation

Pathogenesis of Cardiovascular and Metabolic Diseases: Are Fructose-Containing Sugars More Involved Than Other Dietary Calories?

There is increasing concern that sugar consumption may be linked to the development of metabolic and cardiovascular diseases. There is indeed strong evidence that consumption of energy-dense sugary beverages and foods is associated with increased energy intake and body weight gain over time. It is further proposed that the fructose component of sugars may exert specific deleterious effects due to its propension to stimulate hepatic glucose production and de novo lipogenesis. Excess fructose and energy intake may be associated with visceral obesity, intrahepatic fat accumulation, and high fasting and postprandial blood triglyceride concentrations. Additional effects of fructose on blood uric acid and sympathetic nervous system activity have also been reported, but their link with metabolic and cardiovascular diseases remains hypothetical. There is growing evidence that fructose at physiologically consumed doses may exert important effects on kidney function. Whether this is related to the development of high blood pressure and cardiovascular diseases remains to be further assessed

Asile et abus = Asyl und Missbrauch ::regards pluridisciplinaires sur un discours dominant = multidisziplinäre Perspektiven auf einen vorherrschenden Diskurs

La question de l’asile polarise l’opinion publique en Suisse depuis quarante ans. Depuis son entrée en vigueur en 1981, la Loi sur l’asile a été révisée à de nombreuses reprises, notamment en vue de durcir l’accès à la procédure d’asile ainsi que les conditions d’accueil. Parmi les discours légitimant cette inflation normative, celui de la « lutte contre les abus » bénéficie d’un large consensus dans l’espace public. Pourtant, ce discours n’a encore jamais fait l’objet d’une analyse approfondie. Le présent ouvrage – collectif et pluridisciplinaire comble cette lacune.Seit vier Jahrzehnten wird die Asylthematik in der Schweiz kontrovers diskutiert. Die zahlreichen Anpassungen des Asylgesetzes seit seiner Einführung im Jahr 1981, sind durch eine Verschärfung der Zugangskriterien zum Asylverfahren und erschwerte Aufnahmebedingungen gekennzeichnet. Unter den zahlreichen Debatten geniesst der Diskurs der «Missbrauchsbekämpfung» im Asylbereich breiten Konsens in der Öffentlichkeit. Trotz dieser Omnipräsenz in der politischen und medialen Diskussion fehlt eine eingehende Analyse des Missbrauchsdiskurs im Asylbereich. Das vorliegende Buch schliesst diese Lücke