OPTIMAL PROTEIN LEVEL IS REQUIRED FOR NORMALIZATION OF TASTE SENSITIVITY IN RATS

The influence of levels of dietary protein on taste sensitivity for so dium chloride and zinc status was studied in rats. Animals were given free access to one of seven graded levels of purified egg protein. (PE P) diets for 28 days. Preference tests for the solution of sodium chlo ride (0.86 and 8.56 mmol/L) versus deionized water were conducted on d ays 19 and 21. Feces, urine and blood were collected for assay of zinc concentrations. Only the rats fed the 8% PEP diet discriminated low c oncentration of 0.86 mmol/L sodium chloride solution. The rats fed ano ther diets discriminated only high concentration of 8.56 mmol/L sodium chloride solution. Twenty percent PEP diet-fed group did not discrimi nate both concentrations of sodium chloride. Zinc in serum concentrati on (r=O.89, p<0.001) and balance (r=0.78, p<0.001) was correlated with dietary protein intake. Serum zinc concentrations of the rats fed the 8 and 10% PEP diets were within the normal range. Retained zinc level s remained constant within the range of 4-8% PEP diets. The present st udy indicates that 8% PEP is optimal dietary protein level to normaliz e taste sensitivity for sodium chloride. (C) 1997 Elsevier Science Inc .