In rodents as well as humans, high stearoyl-coenzyme A desaturase-1 (SCD1) activity is considered to be involved in development of obesity. In animal models, polyunsaturated fatty acids (PUFA) inhibit Scd1 gene expression and at the population level, dietary PUFA and plasma PUFA show strong inverse associations with plasma SCD indices. Emerging evidence also suggests a role for the sulphur amino acid cysteine in regulating SCD1 activity and obesity.~The overall aim of the project is to examine if interventions that lowers SCD1 activity lead to increased energy metabolism. In this project, the investigators will conduct dietary intervention trials to evaluate the effects of short-term consumption of a diet rich in polyunsaturated fatty acids (PUFA) and low in cysteine and its precursor methionine (PUFA-Cys/Met) vs. a diet rich in saturated fatty acids (SFA) and cysteine/methionine (SFA+Cys/Met) on SCD1 activity, lipids, amino acids, glucose and other biomarkers related to energy metabolism, in healthy normal-weight subjects. Healthy volunteers will be randomized to the PUFA-Cys/Met or SFA+Cys/Met diets receiving supplements/meals in a single dose or for 7 days.~This study is a pilot study, with main focus on feasibility, tolerance and side effects. If the pilot shows positive results in terms of side effects, safety and tolerance, the investigators will follow-up by including obese subjects in a longer dietary intervention.
The aim of this study is to examine if changing stearoyl-coenzyme A desaturase-1 (SCD1) activity through dietary interventions can increase energy metabolism in humans.