Nwoha P U
Department of Anatomy and Cell Biology, College of Medical Sciences, Obafemi Awolowo University, Ile-Ife, Nigeria.
Contraception. 1992 Dec;46(6):537-42. doi: 10.1016/0010-7824(92)90118-d.
This study investigated the effects of increase in temperature and in pH of Coca-Cola, Afri-Cola, Pepsi-Cola and Krest bitter lemon drinks ("soft drinks") produced in Nigeria on the in vitro motility of spermatozoa. Semen was collected from 7 men, average age 28 years, of proven fertility, after 5 days' abstinence from sexual intercourse. The temperature and pH of the drinks were adjusted from 22 degrees C (room) to 37 degrees C, and pH 2.4 (acid) to 7.5 (alkaline), respectively. The mean % motility of spermatozoa in the adjusted and in the unadjusted drinks was compared for significant differences at the 1% level using the student's t-test. The results showed no significant differences in mean % motility in the drinks at 22 degrees C and at 37 degrees C. The mean % motility in all the drinks, except Coca-Cola, was significantly greater at alkaline than at acid pH; for Coca-Cola, motility was significantly greater at acid than alkaline pH. Of the drinks, Krest bitter lemon (unadjusted) immobilized all spermatozoa within 1 minute of addition.
i) alkalinity decreases the spermicidal action of all drinks except Coca-Cola, and ii) Krest bitter lemon may achieve very high efficacy if used as post-coital douche, especially in the impoverished, densely populated Third World.
本研究调查了尼日利亚生产的可口可乐、阿弗里可乐、百事可乐和克雷斯特苦柠檬水饮料（“软饮料”）温度升高及pH值变化对精子体外活力的影响。在7名经证实具有生育能力、平均年龄28岁的男性禁欲5天后采集精液。将饮料的温度和pH值分别从22摄氏度（室温）调至37摄氏度，pH值从2.4（酸性）调至7.5（碱性）。使用学生t检验比较经调整和未经调整的饮料中精子的平均活力百分比，以确定在1%水平上是否存在显著差异。结果显示，在22摄氏度和37摄氏度时，饮料中精子的平均活力百分比无显著差异。除可口可乐外，所有饮料在碱性pH值下的平均活力百分比均显著高于酸性pH值；对于可口可乐，酸性pH值下的活力显著高于碱性pH值。在这些饮料中，克雷斯特苦柠檬水（未调整）在添加后1分钟内可使所有精子失去活力。
i）碱度会降低除可口可乐外所有饮料的杀精作用，ii）如果用作性交后灌洗，克雷斯特苦柠檬水可能具有很高的功效，尤其是在贫困、人口密集的第三世界。
