Preference for sodium chloride is reduced in protein-deprived juvenile rats.
The influence of dietary protein levels on the preference for sodium chloride was studied in juvenile rats fed diets containing 0, 25 or 50 g purified egg protein/kg and 20.0 mg zinc/kg diet. Preference tests between aqueous solution of NaCl (2-51 mmol/L) or deionized water were conducted. Blood samples were collected for measuring the serum zinc concentration. Scanning electron microscopy was performed to observe the rats' tongue epithelia. Only the rats fed 50 g purified egg protein/kg diet preferred the lowest concentration of 2 mmol/L NaCl solution to deionized water, whereas the rats fed protein-free diet did not discriminate diluted NaCl solution until the concentration was 9 mmol/L. The filiform papillae of the protein-free diet fed group showed significantly less development than the 25 g purified egg protein/kg and the 50 g purified egg protein/kg diet-fed groups. The more protein the diets contained, the higher was the serum concentration of zinc. Significant correlations were observed between protein intake and discriminated NaCl concentration (r = -0.93, P < 0.001), serum zinc (r = 0.90, P < 0.001) or length of filiform papillae (r = 0.93, P < 0.001). The present study suggests that taste preference is impaired by protein malnutrition and this may be related to zinc status.
Ohara
I
I
Laboratory of Nutrition, Faculty of Home Economics, Kobe Women's University, Japan.
Tabuchi
R
R
Kimura
M
M
Itokawa
Y
Y
D000818:Animals; D004044:Dietary Proteins / Q000008:administration & dosage* / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005518:Food Preferences; D008297:Male; D008855:Microscopy, Electron, Scanning; D051381:Rats; D017207:Rats, Sprague-Dawley; D017673:Sodium Chloride, Dietary / Q000008:administration & dosage; D013649:Taste / Q000187:drug effects; D014059:Tongue / Q000187:drug effects / Q000648:ultrastructure; D015032:Zinc / Q000008:administration & dosage / Q000097:blood
D004044:Dietary Proteins; D017673:Sodium Chloride, Dietary; D015032:Zinc