Long-term effects of excess sucrose ingestion on three strains of rats

We placed groups of spontaneously hypertensive rats (SHR), Wistar-Kyoto rats (WKY) and a local strain of normotensive Wistar rats on 5 different diets. Our baseline diet (I) derived a near equal number of calories from sucrose, proteins and fats, ie, 1/3 of total calories was provided by each macronutrient. Two other diets (II,III) derived the majority of calories from sucrose with less calories from proteins or fats respectively. The last two diets (IV,V) were relatively low in sucrose with a higher percentage of the total calories from proteins or fats respectively. The rats were assigned to the special diets at 3 months of age. They have now been ingesting these diets a total of 12 months. In SHR, the diets highest in sucrose calories (II,III), in contrast to diets I,IV and V, were associated with a markedly increased blood pressure (BP) at 3 months. The difference of approximately 20 to 30 mm Hg has held over 12 months. In contrast, the normotensive Wistar rats consuming diets II and III showed significant differences in BP (approximately 10 mm Hg) only after 12 months. The response of WKY was intermediate. Some clearcut elevation of BP, although not statistically significant, in WKY consuming diets II and III was present by 3 months. This difference became greater with time (20 mm Hg at 12 months). Consistent changes in body weights between the rats on the different diets were lacking. We conclude that excess ingestion of sucrose can cause chronic elevations in BP, the pattern of which varies among rat strains.