Role of sugars in the pathogenesis of human metabolic diseases
The metabolic effects of pure fructose and of fructose contained in sucrose has been the main research topic in our laboratory for the past 30 years. Our group has previously shown that fructose elicits a higher thermic effect than glucose, but can impair hepatic insulin sensitivity, stimulate hepatic fat secretion, and increase intrahepatic fat storage. Present studies aim at assessing how deleterious effects of high fructose diets can be alleviated by specific nutrients (proteins, amino acids, polyunsaturated fatty acids) and by exercise.
Non-metabolic effects of caloric and non-caloric sweeteners
Beside direct metabolic effects, there is increasing concern that sweeteners may exert deleterious effects of their own. These effects appear to be linked to activation of sweet taste receptors in the mouth, which elicit activation of dopaminergic reward pathways in the brain. These effects may be responsible for overfeeding associated with consumption of sweet products. In addition, there is concern that activation of sweet receptors by non-caloric sweeteners without the simultaneous administration of energy may somehow disrupt the normal mechanisms regulating food intake. We presently assess in healthy volunteers, how artificial, non-caloric sweeteners affect food intake behaviour and the brain responses to food viewing. We also assess whether sweet receptors modulate the secretion of stress hormones and/or gut factors.
Metabolic effects of physical activity
Several studies are performed to assess the effects of acute exercise and of endurance or resistance training on diet-induced insulin resistance. Present studies are mainly focused on the role of hepatic lactate production during exercise or after fructose ingestion in muscle energy production.
Development of monitoring device for adapted physical activities
Together with Dr V. Lecoultre, F. Tache and Ch. Bulliard, at the Centre Métabolique de l’Hôpital Intercantonal de la Broye, we are involved in the development of lifestyle interventions and of adapted physical activity for the prevention of metabolic diseases. In parallel to these clinically-oriented activities, we are presently developing in collaboration with L. Emmenegger and B. Tuzson in the Laboratory for Air Pollution / Environmental Technology, Empa, Duebendorf, a novel breath acetone analyzer, to be used for monitoring adapted physical activities interventions.