Years ago I read in a bodybuilding magazine the rationale for a well-known bodybuilder’s avoidance of drinking milk, especially prior to major contest appearances. “Milk comes from cows,” he noted, “and cows are females. As such, they produce milk rich in estrogens.”
Even the word estrogen strikes horror in the heart of any bodybuilder, because the hormone is associated with excess water retention, increased subcutaneous bodyfat and, in men, gynecomastia, which is the development of breast tissue, a condition often described by the vaguely misogynistic term, “bitch tits.”
Female bodybuilders also prefer to be relatively low on estrogen, not because of any desire to be transformed into men but rather because of its fat-building properties. Indeed, estrogen is largely responsible for the often stubborn fat deposits that plague women’s thighs and hips.
Bodybuilders who use anabolic steroids that aromatize must contend with elevated estrogen. Not all steroids produce that effect, although some popular versions, such as testosterone injections, are subject to conversion into estrogen by way of the ubiquitous enzyme aromatase, which is found in bodyfat, muscle, brain and other tissues. Savvy drug-using competitors deal with the estrogen problem by adding other drugs that either inhibit aromotase or interfere with the binding of estrogen to its cellular receptor. An example of the latter is Nolvadex, a.k.a. tamoxifen citrate. What few bodybuilders know, however, is that Nolvadex works because of its structural similarity to estrogen. If taken too long or in too large a dose, Nolvadex itself begins to act like a genuine estrogen.
What about those who avoid all anabolic steroid drugs? Is estrogen a concern for them too? According to highly controversial research, some substances can mimic or interfere with the actions of several types of hormones in the body, including estrogen, testosterone and thyroid hormones. They are industrial, man-made chemicals of various types, including pesticides and plastics.
Dumping such chemicals in streams and waterways has had definite effects on wildlife. Beginning in the 1960s, anomalies turned up in various animal species, the only commonality being exposure to certain chemicals. Examples: seagulls showing both male and female sex organs, eagles with crossed beaks, panthers born with undescended testicles, alligators with shriveled penises and fish with sex organs that weren’t decisively male or female.
Even earlier, there were signs that human hormone systems weren’t immune to the effects of chemicals. In the 1940s women were prescribed a type of synthetic estrogen called DES to prevent miscarriages. It seemed safe until years later, when the sons and daughters of DES mothers developed rare forms of cancer, dysfunctional immune systems, increased rates of depression and genital abnormalities.
These days we’re exposed to countless chemicals that many scientists think can either mimic or interfere with hormones in the body. As a class, the chemicals are known as hormone disruptors and have been blamed for everything from infertility to obesity to cancer. Many chemicals that can affect hormonal activity, as the pro bodybuilder described above noted, are compounds that occur naturally in foods. It’s virtually impossible to avoid the effects of hormone disruptors. The big debate, however, is whether we have anything to worry about in the first place.
As for the Endocrine Disruptors…
The United States Environmental Protection Agency defines an endocrine disruptor as “an exogenous agent that interferes with the synthesis, transport, binding, action or elimination of natural hormones in the body that are responsible for the maintenance of homeostasis, reproduction, development or behavior.”
The origin of the endocrine disruptor hypothesis is traceable to several events. The first was the impact of DES on the offspring whose pregnant mothers had used the drug decades earlier. A 1994 study reported reproductive problems, including small phallus, in alligators from Lake Apopka, Florida, which had been contaminated by a large spill of the pesticide DDT. A study from Denmark documented a 50 percent decline in men’s sperm counts between 1938 and 1990. Another study, published in 1996, found that various combinations of hormone disruptors can act synergistically—that is, even when exposure to any particular hormone disruptor was small, exposure to several produced far stronger effects.
Estrogenlike hormone disruptors have relatively weak estrogen activity in the human body, far weaker than natural estrogen compounds found in foods. For example, the notorious DES is half as potent as 17-beta estradiol, the most potent human estrogen. Bisphenol-A, a chemical commonly found in plastics, including water bottles, is 15,000 times less potent than estrogen. DDT, a pesticide banned in the United States in 1970, is 8,000,000 times less potent than estrogen.
Animal exposure to hormone-disrupting chemicals usually involves exposures far greater than most humans experience. The study that identified hormone disruptor synergies proved to be flawed, the authors later retracting their original findings. The study finding a decline of sperm counts in human males has been contradicted by research show little or no changes in sperm counts over the years.
Still, it’s hard to avoid exposure to ubiquitous hormone-disrupting chemicals. Foods recommended for their health benefits, such as fruits and vegetables, often have pesticide residue on the outside, which explains why they should be washed before being eaten. Fish, touted for their high omega-3 fatty acid content, may harbor pesticide residue. Chemicals in plastics may convert in the body into compounds that act like estrogens, and people who drink bottled water to avoid the alleged impurities in tap water may instead be swallowing those chemicals. Plastic food wrappings may leach into hot foods, again putting unwanted synthetic estrogenlike chemicals into the body.
Common hormone-disrupting chemicals include dioxins, which are by-products of industrial incineration and combustion. Dioxins come from products containing chlorine—for example, pesticides, wood preservatives and bleached paper used for coffee filters. Dioxins lower measures of thyroid hormone and testosterone while producing estrogenlike effects.
Polychlorinated buphenyls are used as coolants, lubricants and insulation for electrical equipment, and they show up in paints, plastics, dyes, wood and rubber. PCBs accumulate in bodyfat, are known to act like estrogen and interfere with thyroid function. In 1979, 2,000 people in Taiwan were exposed to PCBs from contaminated cooking oil. Only 46 percent of the children born to young men exposed to such a high level of PCB were boys, compared to the world average of 51 to 52 percent. The theory is that PCBs may have selectively injured Y-sperm, which produces males. Females were unaffected.
Bisphonal-A, found in plastics, was first identified with estrogen in a 1938 study of rats. Pregnant mice exposed to the chemical at a strength equal to that of typical human exposure produced male offspring with enlarged prostate glands and low sperm production. Later studies implicated it in breast cancer when plastic test tubes containing bisphenol caused cell changes similar to that of breast cancer.
The problem with bisphenol-A is that it leaches into food. That most commonly occurs with hot, high-fat foods, such as hamburgers and cheese. In a recent review of 700 prior studies, a group of scientists concluded that human exposure to bisphenol-A exceeds the dose shown to cause harm to lab animals. In fact, 95 percent of people tested had potentially harmful measures of bisphenol in their bodies.
Phthalates are additives that make plastics strong, soft and flexible. They’re also used in paints, glues, insect repellents, hair spray, nail polish, lotions, shampoos, deodorants and hair coloring, as well as in the manufacture of enteric-coated medications.
Consumer Reports tested commercial food wraps to see if the plastic leached into prepared foods. Cheese was the designated testing substance because chemicals concentrate in fatty foods as well as human bodyfat. The tests revealed the presence of phthalates in the food, although the head researcher felt that the plastic wrapping was too low in phthalate and that it probably came from the food itself, since the chemical was so ubiquitous in the environment. Another recent study found that phthalate metabolites are capable of altering human thyroid hormone synthesis.1
Exposure to phthalates has been linked to abdominal obesity and insulin resistance.2 Pthalates are known to lower testosterone counts in men and adversely affect sperm quality. Researchers suspect their testosterone-lowering properties are responsible for abdominal-fat increase. That has proven links to insulin resistance, which in turn is linked to a host of degenerative diseases. The study cites the sobering fact that 75 percent of people in the United States have measurable amounts pthalates in their urine samples.
Exposure to hormone-disrupting chemicals similar to estrogen encourages bodyfat buildup. Estrogens stimulate a process called fat-cell hyperplasia, whereby the cells divide and form new fat cells. Bisphenol-A is closely linked to fat-cell differentiation, or the formation of new fat cells. Once formed, the new fat cells are present for good, making it that much harder to lose bodyfat. Bisphenol-A and PCBs can also trigger chronically elevated insulin, leading to insulin resistance and diabetes. Researchers have found that exposure to six common chemical pollutants led to a prevalence of diabetes 38 times greater than the lowest degree of exposure to the chemicals.3
Exposure to short-acting insecticides has recently been linked to low testosterone in men.4 Until 2000, for example, the chemical chlorpyrifos or its metabolite TCPY was one of the most common insecticides used in homes, but it was restricted after the Environmental Protection Agency found evidence that it can affect the central nervous system. The newer study describes the impact on testosterone. TCPY, by the way, has been detected in the urine of more than 90 percent of men. Another compound, called 1-naphthol, is a breakdown component of carbaryl, a lawn and garden insecticide known as Sevin, and the compound naphthalene, found in cigarette smoke, diesel fuel and other combustion products. The presence of 1N in men’s urine is associated with decreased concentration and motility of sperm, as well as DNA damage in sperm cells.
Even ozone is known to adversely affect sperm counts. From 1996 to 1999 one researcher evaluated 8,513 samples from sperm donors in Los Angeles and 5,574 samples from 35 donors in Northern California. The average donor age was 25, and most were college students. Results: The greater the exposure to ozone, the lower the sperm count.
Another suspected hormone disruptor is triclosan, commonly used as an antibacterial agent, especially in soaps but also in dishwashing detergent, deodorants, cosmetics, acne medications, toothpaste, mouthwash and other products. Triclosan is a chlorophenol, a class of chemicals suspected of being carcinogens. It’s known to interfere with thyroid function, thus marking it as a hormone disruptor. When exposed to chlorinated water, triclosan reacts to create chloroform, another possible carcinogen. Structurally, triclosan is similar to the infamous Agent Orange used during the Vietnam War.
Hormone Disruptors in Food
Soy products have a reputation as a hormone disruptor that acts like an estrogen and lowers testosterone counts in men. Soy’s isoflavones, such as genistein, are structurally similar to estrogen. Those and other natural substances in plants that look like estrogen are collectively known as phytoestrogens, or plant estrogens. Their many health benefits are well known; indeed, one of the hottest supplements available is resveratrol, a phytoestrogen found in red wine and various plants that is extolled for its many health benefits.
Soy is put into supplements targeted for bodybuilding use. Critics say that eating soy will lower testosterone, but that’s hardly confirmed in the literature. And a good thing, too, because you’d find it difficult to avoid phytoestrogens, which are found in more than 300 plants and in 16 common plant families. Estrogens naturally occur in beans, cereals, fruits and vegetables.
One recent study found that corn contains a substance that is capable of causing hormone disruption.5 Although you’d have to eat a lot of corn to reach chemical toxicity, corn-based food products are abundant. Just look at all the corn oil and high fructose corn syrup on food-ingredient labels.
Since many otherwise healthful foods, including fruits and vegetables, are coated with potential hormone disruptors, it raises the question of how to respond as eater and bodybuilder. Here’s a list of ways to avoid being exposed to hormone-disrupting chemicals:
1) Buy only organic fruits and vegetables.
2) Eat only hormone-free meats, eggs and dairy products.
3) Try switching to grass-fed beef.
4) Drink out of glass rather than plastic bottles.
5) Use natural soaps and detergents free of triclosan.
6) Use natural pesticides and insecticides.
7) Use natural and organic cosmetics free of phthalates.
8) Avoid most plastics.
9) Store food in glass or ceramic containers.
10) Do not heat food in plastic containers with plastic wrap over the top.
11) If you choose to buy produce that is not organic, make sure you rinse it thoroughly before eating.
Finally, don’t panic. The human body has an efficient detoxifying system in the liver, consisting of phase-2 enzymes. Eating foods that stimulate the natural detox system, such as cruciferous vegetables—broccoli, cabbage, kale and brussels sprouts—will help degrade potential hormone disruptors before they have a chance to do their dirty work. Just make sure you wash the veggies first.
1 Meeker, J.D., et al. (2007). Di (2-ethylhexyl) phthalate metabolites may alter thyroid hormone levels in men. Environ Health Perspect. 115:1029-34.
2 Stahlut, R.W., et al. (2007). Concentrations of urinary phthalate metabolites are associated with increased waist circumference and insulin resistance in adult U.S. males. Environ Health Perspect. 115:876-82.
3 Lee, D.H., et al. (2006). A strong dose-response relation between serum concentrations of persistent organic pollutants and diabetes: Results from the National Health and Examination Survey 1999-2002. Diab Care. 29:1638-44.
4 Meeker, J.D., et al. (2006). Exposure to nonpersistent insecticides and male reproductive hormones. Epidem. 17:61-68.
5 Markaverich, B., et al. (2002). Identification of an endocrine disrupting agent from corn with mitogenic activity. Biochem Biophys Res Commun. 291:692-700. IM