Unlike chicken, which has largely been ignored by PCa-Diet studies, beef has been scrutinized for a quarter of a century. Almost all of the studies are American. According to one beef industry source, Americans eat about 80 lbs of beef each year. Pork is about 51 lbs. Unfortunately, most of these studies use the term "red meat" to include pork ("The other white meat.") I had no choice but to include the "red meat" studies as being basically, beef studies.
I noted a basic assumption in earlier studies, that saturated fat must be bad for the prostate, rather than the meat. No explanation as to the mechanism, however. It's lazy to take a supposed cardiovascular risk factor & assume a cancer connection. Also, the CVD connection has been unravelling somewhat. Stearic acid is a major dietary saturated fat - 18 carbons, fully hydrogenated. Some call it beef tallow; candles are made of it. & yet stearic acid has a neutral effect on cholesterol when it replaces carbohydrate.
Different countries have different traditions as to how beef is reared & cooked. In the U.S. aince WWII, animals spend time before slaughter on feed lots. This is happening to some extent now, even in countries like Argentina & also parts of Europe. But, for all U.S. studies, one must assume that the cattle spent 3-6 months on a feed lot eating mostly corn & other grain. While weight gain is rapid, the feed causes gastrointestinal distress, which necessitate antibiotics. I don't really know why they would help. The cattle lack the microbes needed to help digest grain.
This is from someone who works on feedlots [1a]:
"Ionophores are probably the most commonly used. You will find them in yards that feed 100,000 head and yards that feed 50 head. They are growth promotants, but the advantages to animal health are often overlooked. They prevent bloat and acidosis. Both of these events happen incredibly fast and are often fatal to cattle. The worst wreck I’ve ever experienced happened when 5,000 yearlings were put on hot ration without monensin. In the end, we lost 50 animals to grain overload. Ionophores also prevent coccidiosis, which can be detrimental to an animals and performance."
The drastic change of diet has profound effects on flesh & fat [1b]:
"Grass-based diets have been shown to enhance total conjugated linoleic acid (CLA) (C18:2) isomers, trans vaccenic acid (TVA) (C18:1 t11), a precursor to CLA, and omega-3 (n-3) FAs on a g/g fat basis."
"grass-finished beef tends toward a higher proportion of cholesterol-neutral stearic FA (C18:0), and less cholesterol-elevating SFAs such as myristic (C14:0) and palmitic (C16:0) FAs.
The use of hormones goes back many years. DES was approved in 1954 but is no longer used.
[1c] "Today, there are six anabolic steroids given, in various combinations, to nearly all animals entering conventional beef feedlots in the U.S. and Canada:
* Three natural steroids (estradiol, testosterone, and progesterone), and
* Three synthetic hormones (the estrogen compound zeranol, the androgen trenbolone acetate, and progestin melengestrol acetate).
"Anabolic steroids are typically used in combinations. Measurable levels of all the above growth-promoting hormones are found at slaughter in the muscle, fat, liver, kidneys and other organ meats. The Food and Drug Administration has set "acceptable daily intakes" (ADIs) for these animal drugs."
Since the purpose of these hormones is to speed growth, one wonders what the effect on cancer is - particularly a hormone-related cancer.
I came to America from England over 40 years ago. A big difference in eating habits that I noticed was (a) Americans ate more beef, (b) Americans ate bigger portions of beef & (c) Americans ate more beef cooked at high heat. Time passed, & American supermarkets introduced fresh fish counters in the 1980's, while the English discovered how to use an outdoor grill. But I think that American men still probably get far more of the chemicals that come from high-heat cooking than English men do. Part of the reason is the meat is quite different. An American steak tastes really good.
Speaking of high heat cooking, The Ruth's Chris steak restaurants cook the meat rapidly at heat that is said to be 1,800 degrees F. All cooking methods denature the protein, but one has to wonder about the chemistry at 1,800 degrees. Yet it tastes good, of course.
 the Health Professionals Follow-up Study [HPFS].
A number of HPFS studies have appeared over the years. Those that follow involve Edward Giovannucci, starting in 1993:
"As of January 31, 1990, 300 new cases of prostate cancer, including 126 advanced cases, were documented in 47855 participants initially free of diagnosed cancer."
"Total fat consumption was directly related to risk of advanced prostate cancer (age- and energy-adjusted RR = 1.79 ... for high versus low quintile of intake ...)."
"This association was due primarily to animal fat (RR = 1.63 ...), but not vegetable fat."
"Red meat represented the food group with the strongest positive association with advanced cancer (RR = 2.64 ...).
"Saturated fat, monounsaturated fat, and alpha-linolenic acid, but not linoleic acid, were associated with advanced prostate cancer risk;"
HOWEVER: "only the association with alpha-linolenic acid persisted when saturated fat, monounsaturated fat, linoleic acid, and alpha-linolenic acid were modeled simultaneously (multivariate RR = 3.43 ...)"
Alpha-linolenic acid is not a saturated fat, of course, it is the omega-3 fatty acid found in flaxseed oil.
"The potential roles of carcinogens formed in cooking animal fat and of alpha-linolenic acid in the progression of prostate cancer need to be explored."
"Between 1986 and 1996, 1897 total cases of prostate cancer (excluding stage A1) and 249 metastatic cancers were identified."
"Intakes of total meat, red meat, and dairy products were not associated with risk of total or advanced prostate cancer."
"An elevated risk for metastatic prostate cancer was observed with intake of red meat (relative risk (RR)= 1.6 for top vs. bottom quintile comparison ..."
"A high intake in both red meat and dairy product was associated with a statistically significant two-fold elevation in risk of metastatic prostate cancer, compared to low intake of both products; however, most of the excess risk could be explained by known nutritional components of these foods."
"... it appears that a portion of the risk of metastatic prostate cancer associated with red meat intake remains unexplained."
[2c] By 2015, they had begun to look at "Intake of Meat Mutagens". These:
"were assessed using a cooking method questionnaire administered in 1996. Until 2010, 2,770 prostate cancer cases were observed among 26,030 participants."
"Intake of PhIP from red meat was statistically significantly associated with total prostate cancer risk (top vs. bottom quintile HR, 1.18 ..." ("PhIP from white meat, 1.08 ...")
PhlP is "2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine". (if that helps)
"For high-grade (Gleason sum 7 with pattern 4+3 and Gleason sum 8-10, n = 483 cases) and advanced cancers (n = 281), we only observed positive associations for PhIP from red meat (top vs. bottom quintile: high grade: HR, 1.44 ..; advanced: HR, 1.50 ...), but associations for advanced cancers did not reach statistical significance.
 (1994 - U.S.). Giovannucci got into this one too:
"In 1982, at the start of the Physicians' Health Study, 14916 U.S. male physicians provided plasma samples, which were frozen at -82 degrees C. Data accumulated from a series of questionnaires were used to assess the intake of various foods. We used a nested case-control design to compare the fatty acid compositions in plasma from 120 men who later developed prostate cancer with 120 matched controls who did not."
"The relative risks (RRs) of prostate cancer for men in successively higher quartiles of plasma alpha-linolenic acid level were 3.0 .., 3.4 .., and 2.1 .., compared with those with levels below the detection threshold"
"The RR for eating red meat at least five times per week compared with less than once a week was 2.5 ..."
HOWEVER: "The association of alpha-linolenic acid levels with prostate cancer was greater among men with low linoleic acid and reduced meat intake."
I tend to think that describes me, circa 2004. I ate little red meat; avoided the vegetable oils high in the omega-6 linoleic acid [LA], & was seduced by the claims made for flaxseed oil omega-3 alpha-linolenic acid [ALA]. It wa a perfect storm. LA & ALA compete for enzymes. LA might not be very desirable, but it shields the body against ALA.
There was a vegan backlash against the earlier study. Somehow, ALA from meat had to be different from ALA from vegetarian sources. But in this study, meat was not implicated in the ALA risk.
"These results suggest that low plasma levels of alpha-linolenic acid might be associated with reduced risk of prostate cancer, independently of high meat intake."
 (1994 - Hawaii)
"Relative risks (RRs) for prostate cancer ... were elevated for intake of beef [RR for highest to lowest tertile of intake = 1.6 ...]"
Not sure one can extrapolate from Hawaii to the rest of the U.S. Or anywhere else.
 (2004 - U.S.)
This one will have you scratching your head (last paragraph):
"The study sample included male participants in the first National Health and Nutrition Examination Survey (NHANES) I Epidemiological Follow-up Study (NHEFS). NHANES I, conducted between 1971 and 1975 ..."
"NHEFS was a longitudinal study of the 14,407 participants between the ages of 25 and 74 years at the time of the initial survey ... Participants were followed for health and vital status through 1992."
"In a nationally representative sample of men, we identified the following three dietary patterns: a vegetable-fruit pattern, a red meat-starch pattern, and a Southern pattern. The red meat-starch pattern was not associated with disease, but intermediate intake of the vegetable-fruit pattern was nonsignificantly associated with increased prostate cancer risk. Intake of the Southern pattern showed a trend that was suggestive of an inverse association and that could not be attributed to any specific foods within the pattern."
 Meat mutagens - specifically PhIP. In addition to the recent HPFS study [2c], there are these earlier studies:
[6a] (2005 - U.S.)
"We prospectively investigated the association between meat and meat mutagens, specifically PhIP, and prostate cancer risk in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial. Diet was assessed using a 137-item food frequency questionnaire and a detailed meat-cooking questionnaire ..."
"Total, red, or white meat intake was not associated with prostate cancer risk. More than 10 g/d of very well done meat, compared with no consumption, was associated with a 1.4-fold increased risk of prostate cancer ... and a 1.7-fold increased risk ... of incident disease."
"the highest quintile of PhIP was associated with a 1.2-fold increased risk of prostate cancer ... and a 1.3-fold increased risk of incident disease"
[6b] (2007 - U.S.)
"The study population consisted of 268 African-American and Caucasian men who underwent radical prostatectomy for prostate cancer."
"PhIP-DNA adducts in tumor and adjacent nontumor cells were measured"
"grilled meat consumption ... was significantly associated with higher adduct levels in tumor cells, but this association seemed to be primarily due to consumption of grilled red meats ... as opposed to grilled white meat consumption ..."
"Among the specific food items, grilled hamburger consumption had the most significant association with adduct level in tumor cells"
[6c] (2011 - U.S.)
"Higher consumption of any ground beef or processed meats were positively associated with aggressive prostate cancer, with ground beef showing the strongest association (OR = 2.30 ..). This association primarily reflected intake of grilled or barbequed meat, with more well-done meat conferring a higher risk of aggressive prostate cancer."
 (2006 - U.S.)
"We examined intake of red meat, processed meat, and poultry in relation to incident prostate cancer among Black and White men in the Cancer Prevention Study II Nutrition Cohort. Participants in the study completed a detailed questionnaire on diet, medical history, and lifestyle in 1992 to 1993. After excluding men with a history of cancer and incomplete dietary information, 692 Black and 64,856 White men were included in the cohort. During follow-up through August 31, 2001, we documented 85 and 5,028 cases of incident prostate cancer among Black and White men, respectively."
"No measure of meat consumption was associated with risk of prostate cancer among White men."
"Among Black men, total red meat intake (processed plus unprocessed red meat) was associated with higher risk of prostate cancer (RR, 2.0 ... for highest versus lowest quartile ...); this increase in risk was mainly due to risk associated with consumption of cooked processed meats (sausages, bacon, and hot dogs; RR, 2.7 ... for highest versus lowest quartile ..."
 (2007 - U.S.)
"In 1989, 3,892 men 35+ years old, who participated in CLUE II study of Washington County, MD, completed an abbreviated Block food frequency questionnaire. "
"Incident prostate cancer cases (n = 199) were ascertained through October 2004."
"Overall, consumption of processed meat, but not total meat or red meat, was associated with a possible increased risk of total prostate cancer in this prospective study. "
 (2008 - UK/Europe)
"This was a multicenter prospective study of 142,520 men in the European Prospective Investigation into Cancer and Nutrition (EPIC)."
"After a median follow-up time of 8.7 y, prostate cancer was diagnosed in 2727 men. There was no significant association between dietary fat (total, saturated, monounsaturated, and polyunsaturated fat and the ratio of polyunsaturated to saturated fat) and risk of prostate cancer."
"There were no significant associations between prostate cancer risk and fat from red meat, dairy products, and fish."
 ((2009 - U.S.) The only study to implicate dietary iron from meat.
"Hazard ratios comparing the fifth intake quintile with the first revealed elevated risks associated with red and processed meat for total (red meat: hazard ratio (HR) = 1.12..; processed meat: HR = 1.07 ...) and advanced (red meat: HR = 1.31 ... processed meat: HR = 1.32) prostate cancer."
"Heme iron, barbecued/grilled meat, and benzo[a]pyrene were all positively associated with total (HR = 1.09 ...), HR = 1.11 .., and HR = 1.09 .., respectively) and advanced (HR = 1.28 .., HR = 1.36 .., and HR = 1.28 .., respectively) disease."
Nitrite (HR = 1.24 ...) and nitrate (HR = 1.31 ...) intakes were associated with advanced prostate cancer."
"There were no clear associations for fatal prostate cancer."
"Red and processed meat may be positively associated with prostate cancer via mechanisms involving heme iron, nitrite/nitrate, grilling/barbecuing, and benzo[a]pyrene."
 The two Erin Richman chicken skin studies.
[11a] (2009 - U.S.) This is from the first:
"Our results suggest that the postdiagnostic consumption of processed or unprocessed red meat, fish, or skinless poultry is not associated with prostate cancer recurrence or progression ..."
[11b] (2011 - U.S.) This is from the second:
"among men initially diagnosed with clinically localized or regional prostate cancer, we observed suggestive positive associations between ... total processed red meat intake and progression to lethal prostate cancer, but these relations were of borderline statistical significance"
My take on this is that red meat can be a safe part of a post-diagnosis diet. However, roast beef & stews are the way to go. If someone offered me the perfect burger today, I would certainly eat it, but it would be my first this year.
Processed meats are out. Mostly because of phosphates, I feel, which can inhibit the production of hormonal vitamin D.
In terms of fat, I think that grass-fed beef has a better profile.
The big surprise (known for over 20 years) is that alpha linolenic acid (an omega-3), from any source, can be dangerous. Ironically, intake is fairly safe when there is enough linoleic acid (the evil omega-6). Too bad for those of us who gave up on the polyunsaturated cooking oils that are high in it. I'll do a separate post on ALA.