Interplay between sugar and salt on blood pressure in spontaneously hypertensive rats

Previous experience showed that sucrose ingestion exceeding 50% of total calories consistently increased systolic blood pressure (SBP) in rats, but ingesting 36 or 13% of calories as sucrose did not. In fact, the mean SBP of rats ingesting 36% of calories as sucrose was not different from rats ingesting 13% of calories as sucrose. This was not the case in the present study where the dietary salt content was increased. Adding dietary salt (NaCl) to raise low concentrations of Na (0.14% wt/wt) to higher concentrations (0.80% wt/wt) in diets with 36 and 13% of calories from sucrose significantly elevated SBP in spontaneously hypertensive rats eating both diets, but significantly more in the former. Accordingly, an interplay exists between sugar and salt in SBP regulation, and it is suggested that amounts of sugar characteristically consumed by an average human are capable of increasing BP. Composition of diets, especially with respect to sugar and salt, should be considered when interpreting results from studies on various aspects of hypertension.