Estrogenic Growth Promoters in Meat

In 1979, an epidemic of breast enlargement was noted in Italian children. Poultry or veal was suspected, given that estrogens “may be fed to farm animals to accelerate their weight gain.” “After this episode, the European Union banned the application/use of anabolic growth promoters in agriculture,” as well as the importation of American meat from animals injected with drugs like Zeranol, sold as “Ralgro Magnum.”

Zeranol, one of the most potent known endocrine disrupters, is 100,000 times more estrogenic than the plastics chemical, BPA, for example, and is the subject of my video Zeranol Use in Meat and Breast Cancer. “Zeranol constitutes a special case among potential endocrine disrupters, because Zeranol, in contrast to all other oestrogenic ‘endocrine disrupting’ chemicals, is present in human food because it is deliberately used in the production of consumer products. Furthermore, Zeranol is designed to be a potent, fairly persistent, [estrogen] whereas the [estrogenic] properties of the chemicals that are considered potential endocrine disrupters is accidental.”

If you drip blood from a cow implanted with the drug onto human breast cancer cells in a petri dish, you can double the cancer growth rate. We don’t drink blood, though, but preliminary data showed that muscle extracts—that is, meat extracts—also stimulated breast cancer cell proliferation.

Furthermore, Zeranol may cause the transformation of normal breast cells into cancer cells in the first place. Zeranol-containing blood from implanted cattle “was capable of transforming the human normal breast epithelial cell line” into breast cancer cells within 21 days.

“[O]bese individuals may be at greater risk of developing zeranol-induced breast cancer,” since they already have high levels of leptin, which is a hormone produced by fat cells that can itself promote breast cancer growth. And, Zeranol exposure can greatly enhance this growth-promoting action. “This result also suggests that Z[eranol] may be more harmful to obese breast cancer patients than to normal weight breast cancer patients in terms of breast cancer development.”

“In conclusion, because the synthetic and the natural hormones, used as anabolic growth promoters in meat production, are by far the most potent hormones found in human food,” we should really be testing people, especially children, before and after eating this meat. It amazes me this hasn’t been done, and, until it has, we have no idea what kind of threat they may pose, though the fact that Zeranol is as potent as estradiol (the primary sex steroid in women) and DES should concern us. DES is another synthetic estrogen that was marketed to pregnant women until 1971 when it was shown to cause vaginal cancers in the daughters. But few know it was also used in meat.

“In the absence of effective federal regulation, the meat industry uses hundreds of animal feed additives…with little or no concern about the carcinogenic and other toxic effects of dietary residues of these additives. Illustratively, after decades of misleading assurances of the safety of diethylstilbestrol (DES) and its use as a growth-promoting animal-feed additive, the United States finally banned its use in 1979 some 40 years after it was first shown to be carcinogenic. The meat industry then promptly switched to other [potentially] carcinogenic additives,” such as Zeranol.

When girls started dying from vaginal cancer, DES-treated meat was banned in Europe. However, “misleading assurances…including the deliberate suppression of residue data, managed to delay a U.S. ban on DES” in the meat supply for eight years.

Today, “[v]irtually the entire U.S. population consumes, without any warning, labeling, or information, unknown and unpredictable amounts of hormonal residues in meat products over a lifetime.” If all hormonal and other carcinogenic feed additives aren’t banned immediately, the least we should have is “explicit labeling requirements of use and of [hormone] residue levels in all meat products, including milk and eggs.”


Isn’t the DES story amazing? I had no idea it was used in meat production. Check out Illegal Drugs in Chicken Feathers for more on Big Pharma on Big Farms.

The most dangerous additive used in the meat industry is antibiotics, though. See, for example:

For more on what may be bad for the breast, check out:

And, for what may be protective, see:

In health,
Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live, year-in-review presentations:

How to Lower Phthalate Exposure Through Diet

Phthalates are hormone-disrupting plastics chemicals linked to a number of adverse health effects, such as disturbing infant and child development, and, in adults, may affect reproductive health in men and endometriosis in women, and is associated with increased abdominal fat in both. “Given the increasing scientific evidence base linking phthalate exposure with harmful health outcomes, it is important to understand major sources of exposure,” which I discuss in my video What Diet Best Lowers Phthalate Exposure?.

What is the most major exposure source? Diet. If you have people stop eating for a few days, you get a significant drop in the amount of phthalates spilling out in their urine. One can only fast for so long, though. Thankfully, we can see similar drops just from eating a plant-based diet for a few days, which gives us a clue as to where most phthalates are found.

The highest levels are found in meats, fats, and dairy. Poultry consistently comes out as being the most contaminated across the board with some of the highest levels ever reported, though there are geographic exceptions. In the United Kingdom, for example, fish came out worse than poultry, and, in Belgium, nothing appears to beat out reindeer meat in terms of contamination. In the United States, though, it is poultry, and the finding that egg consumption is also significantly associated with phthalate levels “suggests that chickens themselves may be contaminated” and not just arise from the plastic they’re wrapped in at the store.

The same might not be true with dairy, however. Realizing that these chemicals may be harmful, researchers in Seattle took ten families and randomized them into a five-day complete dietary replacement with fresh organic foods without any packaging. Nothing touched plastic. Organic milk was delivered in glass, and even the crates used to carry the food were wooden instead of plastic. This was like a fasting study to see what role eliminating processed foods would have on lowering phthalate levels because not everyone wants to switch to a plant-based diet—or stop eating completely. In my video, I show a chart depicting where the families started at baseline before changing their diet and where they were a week after the experiment, once again back on their baseline diet. What happened in the middle? When eating fresh and organic food, their phthalate levels went up, “a dramatic and unexpected increase in one of the most toxic phthalates—and not just by a little: It was like a 2000 percent increase. So the researchers tested all the foods. One of the spices was off the chart, and so was the dairy. Most of the phthalates apparently don’t come from the cow, however; they come from the tubing. If you milk cows by hand (which even the Amish don’t do anymore) the levels of phthalates in the milk are low, but if the same cows are milked by machine, the milk picks up phthalates from the tubing. As such, the final levels may depend more on the tubing than on what the cows are fed.

We’re not sure where the chickens are getting contaminated with phthalates, though. While that study was done on adults, we learned more recently where our kids may be getting it. Researchers found pretty much the same thing: mostly meat, including poultry and fish. Again, poultry appeared to be the worst, while soy consumption was associated with significantly lower levels. But what kind of exposure are we talking about? Researchers calculated what may be typical exposures for infants, teens, and women. How do these data compare with current guidelines? The U.S. Environmental Protection Agency’s reference dose, which is like the maximum acceptable threshold, is 20 µg/kg-day, based on liver risk. Europe places their maximum daily intake for testicular toxicity at 50 µg/kg-day. So a typical infant diet exceeds the EPA’s safety level, “while a diet high in meat and dairy was over this threshold by approximately four times. For adolescents, a diet high in meat and dairy also exceeded the EPA’s reference dose.” Indeed, diets high in meat and dairy consumption resulted in a two-fold increase in exposure. And “[a]ll diets for all groups exceeded the allowable daily intakes (ADI) derived by the US Consumer Product Safety Commission” for problems with sperm production, while diets high in meat and dairy consumption may exceed the allowable intake for risk of reproductive birth defects as well.


For more information on dietary sources of phthalates, I encourage you to watch both Chicken Consumption and the Feminization of Male Genitalia and Lowering Dietary Antibiotic Intake. Diet isn’t the only way one can be exposed internally, though. See my video Avoiding Adult Exposure to Phthalates, which discusses the risk in both children’s and adult toys.

In health,
Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live, year-in-review presentations:

How Much Vinegar Every Day?

Consuming vinegar with a meal reduces the spike in blood sugar, insulin, and triglycerides, and it appears to work particularly well in those who are insulin resistant and on their way to type 2 diabetes. No wonder the consumption of vinegar with meals was used as a folk medicine for the treatment of diabetes before diabetes drugs were invented.

Many cultures have taken advantage of this fact by mixing vinegar with high glycemic foods. For example, in Japan, they use vinegar in rice to make sushi, and, in the Mediterranean, they dip bread into balsamic vinegar. Throughout Europe, a variety of sourdough breads can lower both blood sugar and insulin spikes. You can get the same effect by adding vinegar to boiled white potatoes then cooling them to make potato salad.

Adding vinegar to white bread doesn’t just lower blood sugar and insulin responses—it increases satiety, or the feeling of being full after a meal. As you can see in my video Optimal Vinegar Dose, a study found that if you eat three slices of white bread, it may fill you up a little, but in less than two hours, you’re hungrier than when you began eating. If you eat that same amount of bread with some vinegar, though, you feel twice as full and, even two hours later, still feel nearly just as full as if you had just eaten the three pieces of bread plain. But this remarkable increase and prolongation of satiety took nearly two tablespoons of vinegar. That’s a lot of vinegar. What’s the minimum amount?

It turns out that even just two teaspoons of vinegar with a meal can significantly decrease the blood sugar spike of a refined carb meal, a bagel and juice, for instance. You could easily add two teaspoons of vinaigrette to a little side salad or two teaspoons of vinegar to some tea with lemon. Or even better you could scrap the bagel with juice and just have some oatmeal with berries instead.

What if you consume vinegar every day for months? Researchers at Arizona State University randomized pre-diabetics to take daily either a bottle of an apple cider vinegar drink—a half bottle at lunch, and the remaining half at dinner—or an apple cider vinegar tablet, which was pretty much considered to be a placebo control: While the bottled drink contained two tablespoons of vinegar, the two tablets only contained about one third of a teaspoon. So in effect, the study was comparing about 40 spoonfuls of vinegar a week to 2 spoonfuls for 12 weeks.

What happened? On the vinegar drink, fasting blood sugars dropped by 16 points within one week. How significant is a drop of 16 points? Well this simple dietary tweak of a tablespoon of vinegar twice a day worked better than the leading drugs like Glucophage and Avandia. “This effect of vinegar is particularly noteworthy when comparing the cost, access, and toxicities” associated with pharmaceutical medications. So the vinegar is safer, cheaper, and more effective. This could explain why it’s been used medicinally since antiquity. Interestingly, even the tiny amount of vinegar in pill form seemed to help a bit. That’s astonishing. And, no: The study was not funded by a vinegar company.

What about long-term vinegar use in those with full-blown diabetes? To investigate this, researchers randomized subjects into one of three groups. One group took two tablespoons of vinegar twice a day, with lunch and supper. Another group ate two dill pickles a day, which each contained about a half tablespoon’s worth of vinegar. A third group took one vinegar pill twice a day, each containing only one sixteenth of a teaspoon’s worth of vinegar. I wasn’t surprised that the small dose in the pill didn’t work, but neither did the pickles. Maybe one tablespoon a day isn’t enough for diabetics? Regardless, the  vinegar did work. This was all the more impressive because the diabetics were mostly well controlled on medication and still saw an additional benefit from the vinegar.


Make sure to check out my other videos on vinegar’s benefits:

This vinegar effect seems a little too good to be true. There have to be some downsides, right? I cover the caveats in Vinegar Mechanisms and Side Effects.

There are a few other foods found to improve blood sugar levels:

The best approach, of course, is a diet full of healthy foods:

In health,
Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live, year-in-review presentations: