1. ¹Division of Cardiology and Nephrology, Department of Medicine, Kyoto Prefectural University of Medicine, Kyoto, Japan
2. ²Department of Nutrition, Kyoto Prefectural University of Medicine, Kyoto, Japan
3. ³Division of Nephrology, Omihachiman Community Medical Center, Shiga, Japan

Correspondence: Tetsuro Kusaba, Division of Cardiology and Nephrology, Department of Medicine, Kyoto Prefectural University of Medicine, 456 Kajii-cho, Kamigyo-ku, Kyoto 602-8566, Japan. E-mail: fwnk5760@mb.infoweb.ne.jp

Received 27 August 2008; Revised 17 April 2009; Accepted 21 April 2009; Published online 10 June 2009.

Abstract

Sodium restriction is important in the treatment of chronic kidney disease; however, it is sometimes difficult to achieve. Decreased taste sensitivity may be a factor influencing inadequate control of oral salt intake and subsequent high blood pressure. To measure this, the gustatory threshold (recognition and detection) for salty taste was determined in 29 patients with chronic kidney disease using a sodium-impregnated test strip and relevant factors determining taste sensitivity were analyzed. Compared with 11 healthy volunteers, recognition and detection thresholds were increased in the patients with chronic kidney disease. Oral sodium intake correlated positively but serum zinc correlated negatively with the recognition threshold. Patients with diabetic nephropathy had a higher detection threshold than non-diabetic patients. Both recognition and detection thresholds were increased in patients with diuretic administration. After 1 week of sodium restriction, the average recognition threshold decreased significantly. Our study verified that latent taste dysfunction and zinc deficiency are common in patients with chronic kidney disease. Further, the recognition threshold for salty taste improved even after a short period of salt restriction.