Women produce the hormones estrogen, progesterone and testosterone in their bodies, but in vastly different amounts. Estrogen is the dominant hormone in a woman's body, responsible for the development of primary and secondary sexual characteristics. In addition, estrogen facilitates the monthly menstrual cycle and its production declines as you reach menopause. Certain foods have naturally occurring or added hormones or substances that act like female hormones in your body. These have the capacity to alter your body's hormonal balance, and can sometimes lead to adverse health effects.
Cow's Milk
Dairy cows have been bred to lactate more frequently in order to supply milk for human consumption. Because estrogen must be increased in the body to elicit lactation, these cows and their milk contain higher amounts of this hormone than would normally be found. A 2005 article published in "Medical Hypotheses" explains that the association between consumption of milk and estrogen-driven types of cancer has increased significantly in a century. In support of this potential influence, a 2010 study published in "Pediatrics International" found significantly higher levels of estrogen in both adults and children who consumed milk from pregnant cows. Like their genetically-altered counterparts, pregnant cows also have higher levels of estrogen in their bodies.
Soy Products
Soy foods such as tofu and soy milk contain substances called phytoestrogens. These chemicals can act like estrogen in your body, by attaching to estrogen receptor sites or by acting like a hormone. The Linus Pauling Institute at Oregon State University explains that although soy products have somewhat weaker estrogen-like effects, they have the capacity to change the way other hormones like testosterone act in your body. While phytoestrogens have been suggested as a mediator for estrogen-driven cancers, the incidence of these cancers is markedly lower in cultures that consume large amounts of soy products.
Lignans
Lignans are a type of polyphenol which are micronutrients that protect cells from the effects of damaging free radicals. Lignans, which include flaxseeds, whole grains and vegetables, are converted into estrogen-like compounds in your intestines. These compounds have weak estrogen-like effects, according to the Linus Pauling Institute at Oregon State University. In addition, lignans may also effect hormones in your body through non-hormonal behaviors such as attaching to estrogen receptor sites or preventing the attachment of estrogen molecules to these sites.
Beef
The U.S. Food and Drug Administration explains that beef cattle are administered steroid hormones in order to increase their growth rate and improve their efficiency in converting feed into meat. While the FDA assures consumers that the amount of steroid hormone found in the beef from cattle is minimal, controversy regarding the effects of hormones in meat continues. John Paterson, Beef Specialist at Montana State University explains that even cattle that are not administered supplemental hormones already have naturally occurring hormones in their bodies. He adds that the amount of estrogen found in a serving of beef from a steer without added hormones is 1.3 nanograms. This amount, he continues, is minimal when compared to the over 400,000 nanograms of estrogen found normally in a woman's body.
References
- "Medical Hypotheses"; The Possible Role of Female Sex Hormones in Milk From Pregnant Cows in the Development of Breast, Ovarian and Corpus Uteri Cancers; D. Ganmaa, et al; 2005
- "Pediatrics International"; Exposure to Exogenous Estrogen Through Intake of Commercial Milk Produced From Pregnant Cows.; K. Maruyama, et al.; 2010
- Linus Pauling Institute at Oregon State University: Soy Isoflavones
- "American Journal of Clinical Nutrition"; Polyphenols: Food Sources and Bioavailability.; C. Manach, et al.; 2004
- Linus Pauling Institute at Oregon State University: Lignans
- United States Food and Drug Administration: Product Safety Information > Steroid Hormone Implants Used for Growth in Food-Producing Animals
- Montana State University; Can Use of Hormones and Antibiotics in Beef Cause Human Problems?; John Paterson
