Diets that are high in sugar can cause health problems such as diabetes and obesity. They can also cause dehydration and have a range of complex effects on metabolism. The effects of a high-sugar diet on health and lifespan are not fully understood, and separating the effects of water imbalance and diabetes-related problems can be challenging.
Helena M. Cochemé, MRC London Institute of Medical Sciences and Imperial College London, both UK, and colleagues have studied the effects of high-sugar diets in the fruit fly Drosophila melanogaster. The team fed the flies either a standard laboratory food containing 5 % sucrose or a high-sugar diet with up to 20 % of sucrose, either with or without added water. Then they monitored the flies’ water intake as a measure of thirst, as well as their lifespan. The team found that flies on a high-sugar diet without added water were dehydrated and died significantly earlier, with a 21 % lower median lifespan than flies on a standard diet. However, with added water, both of these effects disappeared and the lifespans returned to normal.
The team investigated the reasons for the reduced lifespan induced by the high-sugar diet without additional water. They found that this diet induced obesity and diabetes-related problems, as expected. However, these were not changed by giving the flies more water and could, thus, not explain the observed lifespans. The researchers then turned their attention to problems caused by dehydration and looked at the flies’ equivalent of kidneys, the Malpighian tubules. They found uric acid accumulation and tubule stones (the equivalent of kidney stones), which could explain the shortened lifespan in the dehydrated flies.
According to the team, the increased levels of uric acid could be caused by dietary sugars acting as precursors for purine biosynthesis, which generates uric acid as a waste product. The work provides a step to understanding the effects of high-sugar diets that are independent of obesity and diabetes-related problems.
- Sugar-Induced Obesity and Insulin Resistance Are Uncoupled from Shortened Survival in Drosophila,
Esther van Dam, Lucie A.G. van Leeuwen, Eliano dos Santos, Joel James, Lena Best, Claudia Lennicke, Alec J. Vincent, Georgios Marinos, Andrea Foley, Marcela Buricova, Joao B. Mokochinski, Holger B. Kramer, Wolfgang Lieb, Matthias Laudes, Andre Franke, Christoph Kaleta, Helena M. Cochemé,
Cell Metab. 2020.
https://doi.org/10.1016/j.cmet.2020.02.016
