Thursday, March 29, 2007


Researcher Shanna Swan links the growth promoters fed to US cattle to adverse health effects:
Swan suggests that the hormones given to cattle to increase their growth, such as testosterone and progesterone, or the pesticides consumed by these animals might be to blame for the lower sperm counts. The hormones, for example, could interfere with testes development in the womb.

Other scientists agree that this could be a plausible explanation: "Even though males don't start producing sperm until puberty, it is during the time in their mothers' wombs, and in the early years of life as an infant, that the testicles develop their capacity to produce sperm," explains Allan Pacey at the University of Sheffield in the UK.
At the end of the article there is this disclaimer, however:
"Given the widespread use of hormones to stimulate animal growth in the US, the findings of this study [are] plausible," says toxicologist Alastair Hay at the University of Leeds in the UK. "However, there are major difficulties with this type of study, not the least of which is asking a woman how often she ate beef whilst pregnant 25 to 30 years ago."

Swan also notes that even if beef consumption might somehow reduce fertility in men, this would not provide a full explanation for the declining sperm counts reported in men in various countries. The sperm count decline in Denmark, for example, cannot be explained by hormones in beef, she says, because the use of growth hormones in cattle never became widespread there.

Pregnant women concerned about a possible link between beef and lower sperm counts in sons should consider reducing their consumption of this meat, Swan says. "It probably won't hurt, with the caveat that she gets enough protein" in her diet from other sources.
When did science make the transition to guesswork?


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