Tabuchi R, Econ M H, Ohara I, Agr D
Faculty of Home Economics, Kobe Women's University, Japan.
J Am Coll Nutr. 1996 Jun;15(3):303-8. doi: 10.1080/07315724.1996.10718602.
We previously reported dietary protein was needed to maintain normal taste function and low serum zinc concentration led due to protein insufficiency [1], but generally zinc has been known to improve taste dysfunction. The present study was designed to determine whether zinc supplementation is effective in maintaining normal taste function at different levels of dietary protein.
Sixty weanling rats were given free access to one of six diets: protein-free, 2.5% and 8% purified egg protein (PEP), and 10 ppm zinc supplementation at each protein level for 28 days. Preference tests between aqueous solution of 1, 2, 5 or 10 mmol/L NaCl vs. deionized water were conducted on days 14, 17, 20 and 23, respectively. Blood was collected for the measurements of serum zinc concentration, and the tongue of each rat was excised for observation by electron microscopic scanning. The number of fungiform papillae with normal taste pores and also the number of rats with abnormal morphological changes on tongue epithelia were recorded.
In basal diet groups, the rats fed 8% and 2.5% PEP diets discriminated 2 mmol/L NaCl liquid, while those fed the protein-free diet discriminated only the highest concentration of 10 mmol/L in this experiment. Serum zinc concentration and the ratio of fungiform papillae with normal taste pores increased with increasing dietary protein level. Abnormal morphological changes of tongue epithelia were observed in the protein-free diet group whether or not it contained additional zinc. No significant differences were observed between the basal and zinc supplemented diets at the other protein levels in the other parameters.
These results suggest that adequate dietary protein is more important in maintaining normal taste function and zinc supplementation did not improve taste function when dietary protein was suboptimal.
我们之前报道过维持正常味觉功能需要膳食蛋白质，蛋白质不足会导致血清锌浓度降低[1]，但一般认为锌可改善味觉功能障碍。本研究旨在确定在不同膳食蛋白质水平下补充锌对维持正常味觉功能是否有效。
将60只断奶大鼠自由给予六种饮食之一：无蛋白、2.5%和8%的纯化蛋清蛋白（PEP），并在每个蛋白质水平添加10 ppm锌，持续28天。分别在第14、17、20和23天进行1、2、5或10 mmol/L NaCl水溶液与去离子水之间的偏好测试。采集血液测量血清锌浓度，切除每只大鼠的舌头进行电子显微镜扫描观察。记录有味觉孔的菌状乳头数量以及舌上皮有异常形态变化的大鼠数量。
在基础饮食组中，喂食8%和2.5% PEP饮食的大鼠能区分2 mmol/L NaCl溶液，而在本实验中，喂食无蛋白饮食的大鼠仅能区分最高浓度10 mmol/L的NaCl溶液。血清锌浓度和有味觉孔的菌状乳头比例随膳食蛋白质水平的增加而增加。无论是否添加锌，无蛋白饮食组均观察到舌上皮的异常形态变化。在其他蛋白质水平下，基础饮食和补锌饮食在其他参数上未观察到显著差异。
这些结果表明，充足的膳食蛋白质对维持正常味觉功能更为重要，当膳食蛋白质不足时，补充锌并不能改善味觉功能。
