The implantation of hormones into U.S. beef cattle may have adverse human health effects
Cleveland Clinic pathologists dissect fast food burgers to see what's inside.
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, 8 times more endometrial cancer and 10 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 in 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 American 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 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 may 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 6-8. 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.
To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring watch the above video. This is just an approximation of the audio contributed by veganmontreal.
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R. Ahmadkhaniha, F. Kobarfard, N. Rastkari, M. R. Khoshayand, M. Amini, and A. Shafiee. Assessment of endogenous androgen levels in meat, liver and testis of iranian native cross-breed male sheep and bull by gas chromatography-mass spectrometry. Food Addit Contam Part A Chem Anal Control Expo Risk Assess, 26(4):453-465, 2009.
Rapid Commun Mass Spectrom. 2000;14(12):1058-65. Consequence of boar edible tissue consumption on urinary profiles of nandrolone metabolites. I. Mass spectrometric detection and quantification of 19-norandrosterone and 19-noretiocholanolone in human urine. Le Bizec B, Gaudin I, Monteau F, Andre F, Impens S, De Wasch K, De Brabander H.
L. Shi, S. A. Wudy, A. E. Buyken, M. F. Hartmann, and T. Remer. Body fat and animal protein intakes are associated with adrenal androgen secretion in children. Am. J. Clin. Nutr., 90(5):1321-1328, 2009.
Please feel free to post any ask-the-doctor type questions here in the comments section and I’d be happy to try to answer them. And check out the other videos on hormones. Also, there are 1,686 other subjects covered in the rest of my videos--please feel free to explore them as well!
For some context, please check out my associated blog posts: Harvard’s Meat and Mortality Studies, Breast Cancer and Diet, Stool Size and Breast Cancer Risk, Eating Green to Prevent Cancer, How Chemically Contaminated Are We?, and Are Bioidentical Hormones Safe?
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The hormones present in cow's milk may help explain the association between certain diseases and dairy consumption.
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