Red Bull might give you wings, but yogurt gives you bigger cojones. Male mice that ate a diet supplemented with yogurt grew larger testicles. The change was dramatic enough to give them a distinctive “mouse swagger” as they compensated for their greater endowment.
The study, by researchers at the Massachusetts Institute of Technology, was intended to examine the effects of yogurt on obesity. Previous research had shown that yogurt could prevent age-related weight gain.
Researchers fed one group of mice a junk food diet—high in fat, and low in fiber and nutrients. A second group ate standard mouse food. One half of each group also received vanilla-flavored yogurt.
At the end of the study, the testicles of the mice that ate yogurt were five percent heavier than those of the standard-diet group, and 15 percent heavier than the junk food group.
These changes were not just superficial. Yogurt-eating mice inseminated their partners faster and produced more offspring. Female mice also benefitted from eating yogurt, with larger litters and more successful weaning of their pups.
Researchers think that probiotic microbes found in yogurt helped make the mice slimmer and healthier, which encouraged growth of the testicles.
Yogurt isn’t just for mice, though. Other researchers are looking at the benefits of yogurt for semen quality in men. Keep that in mind next time your girlfriend offers you yogurt for lunch.