Endocrine Abstracts

Observational studies conducted during the past two decades provide evidence of an association of dietary fructose consumption with obesity and metabolic diseases as non-alcoholic fatty liver disease or insulin resistance / type 2 diabetes mellitus. However, these associations are challenged by the fact that it is difficult to adjust the results of such studies for excessive caloric intake, which often co-exists with high fructose intake, e.g., by consumption of sugar-sweetened beverages. Thus, there is a clear need for direct interventional studies exploring a possible causal role of fructose in the development of metabolic diseases, as compared to other sugars. To this aim, different controlled trials were conducted by our group as well as other investigators to assess this question. Such studies expose their participants to various amounts of different sugars for several weeks to months, and investigate different outcomes related to metabolic diseases as those outlined above. With these trials, it was possible to gain direct insights into the mechanisms by which different sugars may negatively influence metabolic health. In particular, latest research provides evidence of very distinct effects of fructose consumption on hepatic metabolism, in particular regarding a “metabolic switch” in hepatic tissue towards de novo lipogenesis. Furthermore, and in addition to the effects of fructose, the co-ingestion of fructose and glucose (which is very common due to their co-existence in the sucrose molecule) may have similar or even more deleterious effects than consumption of fructose alone. Thus, these results emphasize the importance of an overall reduction of added sugars in our diet, as suggested by the WHO and other organizations.