For four weeks, rats were exposed to mild heat-induced dehydration followed by access to water, water containing the fructose and glucose content of a typical soft drink, or water with stevia. Fructose and glucose, which are sugars that naturally occur in food, are added to soft drinks for sweetness. Stevia is a sugar substitute derived from a plant and has no calories.

Rats that drank the fructose-glucose water after repeated heat-induced dehydration were more dehydrated and had worse kidney injury than rats that drank plain water or water with stevia. “Our studies raise serious concerns for the common practice, especially among adolescents and young adults, to drink soft drinks as a means to quench thirst following an episode of dehydration,” the authors wrote.

Members of the research team are inventors on patent applications for drugs to prevent kidney injury by blocking fructose metabolism and have funding from Amway and Danone.

The article “Rehydration with soft drink-like beverages exacerbates dehydration and worsens dehydration-associated renal injury” is published in the American Journal of Physiology—Regulatory, Integrative and Comparative Physiology.