Intervention and Observational Trials are Complementary in Metabolomics: Diabetes and the Oral Glucose Tolerance Test

Observational experimental designs are usually employed in metabolomics to elucidate pathological mechanisms underlying disease development and to discover candidate biomarkers for diagnosis. However, intervention trials can also be a suitable starting point before performing a validation study in lager epidemiological cohorts, with a great potential in personalized medicine to investigate how different patients respond to similar stimuli. In the present work, we provide a review of the literature on the application of metabolomics to investigate metabolic alterations associated with diabetes, the diabetes predisposing state of insulin resistance and the oral glucose tolerance test as a case study to demonstrate the complementarity of observational and interventional study designs.