Our Reproductive Health: What Are The Risks?

For Rosemarie Hernandez, 63, her diagnosis of metastatic breast cancer ten years ago was a wake-up call. A mother of three and special-education teacher, she was eating fatty fast foods rather than preparing healthy meals. "I think food does play a part in cancer. If you don't eat right you put yourself at risk," she says.

Hernandez credits a New York City-based oncologist, Mitchell Gaynor, M.D., with saving her life. Gaynor, founder and president of Gaynor Integrative Oncology and assistant clinical professor of medicine at Weill College, practices what he calls integrative oncology, which, in addition to giving medical treatments, seeks to reduce nutritional factors, environmental toxins and stress that may contribute to cancer. "Food is our single biggest source of exposure to environmental toxins," says Gaynor, who advises that patients reduce consumption of saturated fats, found in red meat and dairy products. Toxins that collect in animal fat include dioxins, known carcinogens that also have been linked to infertility. Dioxins are by-products of PVC vinyl production, chlorine bleaching and waste incineration.

Hernandez gave up beef and most dairy products, coffee and processed foods. Sometimes she eats organic chicken, but the bulk of her diet consists of organic fruits and vegetables, grains and fish. She is now in remission.

Breast Cancer, Estrogen and Estrogenic Chemicals

Almost 40,000 women are expected to die from breast cancer in 2003 and an estimated 267,000 new cases will be diagnosed, according to the American Cancer Society (ACS). Although startling gains in new cases during 1980-87—almost 4 percent a year—abated to about six-tenths of a percent annually from 1987 through 2000, the incidence of breast cancer continues to rise. ACS attributes the increases to better detection using mammograms as well as to "changes in reproductive patterns" such as delayed childbearing and having fewer children, which affect one's exposure to estrogen. "The higher the levels and the longer you are exposed to estrogen, the greater your chances of getting breast cancer," Gaynor says. Lab research shows that some synthetic chemicals, such as bisphenol-A—found in some plastics—can behave like estrogen, causing breast-cancer cells to proliferate.

The Rise of Endocrine Disruptors

In addition to bisphenol-A, other chemicals—such as dioxins, phthalate plasticizers, polychlorinated biphenyls (PCBs) and dichlorodiphenyltrichloroethane (DDT)—are thought to be endocrine-system disruptors (EDs), which can either imitate or block naturally occurring hormones in our bodies. Because of their effects on lab animals, EDs are suspected of playing a role in such human health problems as cancer, infertility, premature birth, learning disorders and birth defects such as hypospadias (a malformation of the penis) and cryptorchidism (hidden testes), the biggest risk factor for testicular cancer. Although PCBs and DDT have been banned in the U.S. for over 20 years, they persist in the environment.

Two 2002 "body burden" studies revealed the extent of human exposures. Researchers from the Mount Sinai School of Medicine, Environmental Working Group (EWG) and Commonweal tested the urine and blood of nine volunteers and found "167 chemicals, of which 76 cause cancer in humans or animals, 94 are toxic to the brain and nervous system, and 79 cause birth defects or abnormal development." The Centers for Disease Control (CDC) found 116 environmental chemicals, including dioxins, PCBs, phthalates, DDT and other pesticides, in 2,500 U.S. citizens during 1999-2000.

Although the effects of endocrine disruptors on wildlife and in laboratory animals are well-documented, it is difficult to determine their effects on humans. For example, exposure to atrazine, a pesticide heavily used on corn in the Midwest, turns frogs into hermaphrodites, according to studies published by Tyrone B. Hayes, Ph.D., associate professor of Integrative Biology at Berkeley. "Atrazine doesn't make hermaphrodites in humans," but, Hayes says, "it is probably connected to breast and prostate cancer."

Recent studies, published in Environmental Health Perspectives (EHP) in April and September 2003 by Shanna H. Swan, Ph.D., research professor of Family & Community Medicine at the University of Missouri-Columbia School of Medicine, discovered that the pesticides alachlor, atrazine and diazinon, which have been found frequently in drinking-water sources, are associated with lower sperm counts in Missouri men. "There are many chemicals now in our bodies and in our environment that have the potential to alter men's semen quality and therefore a couple's fertility," says Swan, referring to her own work as well as to recent studies linking phthalates to reduced sperm counts and chromosomal damage in the head of sperm.

According to Linda S. Birnbaum, Ph.D, director of the Experimental Toxicology Division of the Environmental Protection Agency (EPA), "dioxin can promote the growth of endometriosis"—a painful condition in which uterine, or "endometrial," tissue, is found outside the uterus, usually in the abdominal cavity, where it may produce scar tissue and thus infertility. Birnbaum is also examining the role that prenatal and other early life exposures to such chemicals may play in the later onset of breast cancer.

Timing of Exposures

The question of timing is a crucial one and may be one of the reasons that it has been hard for researchers to directly link endocrine-disrupting chemicals to breast cancer in humans. In a study published in May 2003 in Occupational and Environmental Medicine, researchers at the University of Liege, Belgium, found that women with breast cancer had higher levels of two pesticides, DDT and HCB (hexachlorobenzene), in their blood than women without cancer. The researchers point out, however, that there is still controversy about a causative link—maybe because we are measuring chemical levels at the wrong time. This charge was made by Swan and other doctors critical of the 2002 Long Island Breast Cancer Study, which found that the pesticides DDT, dieldrin and chlordane did not increase the risk of breast cancer.

"For many types of chemicals, the critical exposure occurs long before you find a tumor," says Birnbaum. "It's especially true with endocrine disruptors. We wrote a paper showing how prenatal exposure to dioxins and atrazine affected the developing breast so that it is more susceptible to cancer." The study appeared in the April 2003 EHP. Early exposures to EDs, some researchers say, can cause irreversible changes in the way the fetus and young children develop. "When you are making the reproductive system, if you mess it up you can't go back and reverse it. What goes on in the fetus can program the way an individual functions for the rest of his or her life," says Frederick S. vom Saal, Ph.D., professor of Reproductive Biology and Neurobiology in the Biological Sciences Division at the University of Missouri. The April 2003 Current Biology reported laboratory studies in which Case Western Reserve researchers found that low doses of bisphenol-A disrupt the way chromosomes line up in mouse eggs. A similar disruption in the way chromosomes line up in human eggs is thought to be a precursor to aneuploidy—the loss or gain of chromosomes, a leading cause of miscarriages and Down syndrome. "If bisphenol-A affects a species like mice, which doesn't have vulnerable eggs, one wonders what it will do in humans," says lead researcher Patricia A. Hunt, Ph.D., Department of Genetics, Case Western Reserve University. In the November 2003 EHP, researchers at the Columbia Center for Children's Environmental Health found four phthalates, known EDs, in personal air and urine samples taken from pregnant women; these chemicals cross the placenta, entering the fetus.

In recognition of the need to focus on the effects of early exposures, an upcoming National Children's Study, funded by a coalition of U.S. government health agencies, will examine the impact of environmental factors, including EDs, on the health and development of more than 100,000 children from before birth until age 21. Until now, chemicals have generally been studied individually, not in combination, although, as Gaynor points out, we are exposed to chemicals in combination in daily life. "We haven't fully evaluated single agents properly yet, so until we do, it is going to be very difficult to evaluate combinations of agents," says Paul M.D. Foster, Ph.D., senior fellow, at the National Institute of Environmental Health Sciences (NIEHS). In the meantime, see "Ten Ways To Reduced Health Risks" to minimize risk for yourself and your family.

Resources

Hormone Deception: How Everyday Foods and Products Are Disrupting Your Hormones—and How to Protect Yourself and Your Family, by D. Lindsey Berkson (McGraw-Hill, 2000)

Dr. Gaynor's Cancer Prevention Program, Mitchell L. Gaynor (Kensington Pub Corp., 1999)

For more info on cancer and environmental factors, see envirocancer.cornell.edu, www.gaynoroncology.com and "Breast Cancer: Industrial Byproduct?" in GG#62.

For more info on endocrine disruptors, see www.ourstolenfuture.org and cbr.tulane.edu.