Transcript: Anabolic Steroids in Meat
Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.
Some hormones we do implant in farm animals, though. Last year, Japanese researchers were lamenting the dramatic increase in hormone-dependent cancers in their country—four times more breast and ovarian cancer; eight times more endometrial cancer; and ten times more prostate cancer—just in the last 25 years. They suspect it might be because they import so much hormone-laden beef from the United States. But just because we implant cattle with hormones doesn’t mean it actually makes it into the meat.
We inject these hormone implants into the ears of cattle, but the ears get chopped off at slaughter, so the U.S. beef industry argues that the hormones don’t get into the meat. But these researchers were suspicious, so they compared the hormone levels in American beef to Japanese beef, where they don’t commonly inject cattle with hormones.
They found up to 600 times the level of estrogens in American beef. So they got the feeling that the increasing consumption of estrogen-rich beef following steroid implantation might facilitate estrogen accumulation in the human body, and could be related to the incidence of hormone-dependent cancers, although further studies are required. For example, eggs may be the greatest source of estrogens in a person’s “normal” diet.
Why would estrogen-rich beef lead to prostate cancer? You think of that more related to male hormones, like testosterone. We inject cattle with that, too. Just like athletes can use doping agents in sports to build up their muscles, in the livestock industry, anabolic steroids are given to cattle to “beef” up their muscles. We don’t just give estrogens; we implant anabolic male steroids with brand names like “Magnum” and “STEER—oid”—some of which contain androgens like testosterone.
Where are these hormones found the most? Researchers in Iran last year compared the levels of testosterone in the meat, liver, and testicles of sheep. What did they find? Interestingly, though testicles produce testosterone, they don’t store it, and so it builds up elsewhere in the body. In fact, the levels of anabolic steroids in meat can be so high that studies have shown that athletes who eat certain kinds of meat can be falsely accused of abusing steroids.
As with dairy, eating meat may also affect prepubescent children, boosting their production of male sex hormones in both boys and girls, which may hasten the first appearance of pubic hair between ages six and eight. Even though the effect was small, the fact that it’s a modifiable factor—something you can change about your child’s diet—makes it potentially relevant.
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