It has often been thought that "grocery store" beef has higher estrogen levels in it than organic beef by many of the top coaches in the world. Some professional body builders spending upto 50 K (I've heard) a year in diet alone. This is such a cool study since I had yet to see any empirical proof of this. Still needs lots more research but very cool indeed.

"The recent increase of hormone-dependent cancers roughly parallels the increasing consumption of beef in Japan. During the past quarter century, hormone-dependent cancers have risen fivefold: 4 times in breast and ovarian cancer, 8 times in endometrial cancer, and 10 times in prostate cancer [1]. Meanwhile, popularization of the Western diet has resulted in a fivefold multiplication of beef consumption in Japan [2]. More than 25% of the beef has been imported from the United States [3], where hormonal steroids including estradiol-17β have been implanted to cattle for growth promotion since the USA Food and Drug Administration approved the first steroid implant in 1956. In the USA, steroid implantation was carried out in 97% of beef cattle in 1999 [4], though the practice is still uncommon in Japan.

We conceived the possible relationship between estrogen concentrations in beef and incidence of hormone-dependent cancers and evaluated the levels of estradiol-17β (E2) and estrone (E1) in USA beef (fat: n = 40; red meat: n = 30) and Japanese beef (fat: n = 40; red meat: n = 30) by liquid chromatography–tandem mass spectrometry (LC-MS/MS; the lower sensitive limits for E2 and E1 were 0.1 and 0.5 pg, respectively) [5]. The beef was raw sirloin steak sold as an ordinary grocery product at supermarkets in Sapporo city and obtained from tens of different stores at intervals of 3 weeks to avoid obtaining the same beef. Then, we measured estrogen concentrations in human uterine endometrial cancer (n = 50), ovarian cancer (n = 50), and normal controls (endometrium: n = 25; ovary: n = 25).

We found that USA beef contained much higher levels of estrogen, particularly E2, than Japanese beef (Figure 1). The median concentrations (pg/g) of E2 and E1 in USA beef fat (14.0, 7.7) were 140 times and 11 times, respectively, higher than those in Japanese beef fat (0.1, 0.7). In red meat, E2 and E1 levels of USA beef (3.8, 1.0) were ∼600 times and 10 times, respectively, higher than those of Japanese beef (0.0, 0.1).

Figure 1.
Estrogen concentrations in beef measured by liquid chromatography–tandem mass spectrometry. (A) Beef fat; (B) beef red meat. Bars indicate median level. P values were determined by the Mann–Whitney U test.
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Estrogen concentrations in beef measured by liquid chromatography–tandem mass spectrometry. (A) Beef fat; (B) beef red meat. Bars indicate median level. P values were determined by the Mann–Whitney U test.
Because steroid implant for cattle always contains E2 as a mixture, the elevated E2 levels in USA beef may have been ascribed to exogenous E2 residue resulting from steroid implantation. On the other hand, nearly zero level of E2 seen in Japanese beef was considered to be the natural endogenous status in beef without steroid implantation.

E2 and E1 levels of endometrial cancer were higher in stage I (400.3, 133.5) and lower in stage III–IV (8.6, 34.7) than normal endometrium (203.9, 83.2). Ovarian cancer also showed higher levels in stage I (470.5, 527.6) and lower in stage III–IV (27.7, 36.3) than normal ovary (385.6, 156.4). The findings indicated that estrogen accumulation appears to play an initial role in the incidence of these cancers.

Accordingly, it is our intuitive 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 to determine the relation for cancer incidence, we should be more aware of dietary estrogen intake from beef following steroid implantation and give mature consideration for the hormonal usage to livestock in the 21st century.

Annals of Oncology, Volume 20, Issue 9, 1 September 2009, Pages 1610–1611,