What are Xenoestrogens & Phytoestrogens and how do they affect hormone imbalance?
On a daily basis, the average person is exposed to numerous foods and other products that have been shown to have an effect on the body’s hormonal balance. Among those that get talked about most are phytoestrogens and xenoestrogens, which are compounds similar in structure to our body’s own estrogens.
Estrogen is a critical hormone in female sexual health and reproduction, and plays an important role in many systems of the body. However, excess levels of estrogen can result in health issues. This is where phytoestrogens and xenoestrogens are thought to likely play a role.
While most foods don’t inherently contain estrogens, phytoestrogens are naturally occurring plant compounds that are structurally, and functionally, similar to our own estrogens, and are found in many common foods. While still debated, many phytoestrogens are considered to be “endocrine disruptors”, meaning they cause dysregulation to our natural hormonal activities. These compounds can mimic estrogen’s activity in the body by binding to the estrogen receptors.
Xenoestrogens on the other hand are a class of environmental toxins that are also defined as endocrine disruptors, as they too have the ability to bind to estrogen receptors and increase estrogenic activity in the body. The majority of these chemicals have been introduced to our environment only in the last few decades through car exhaust, industrial pollutants, pesticides, cigarette smoke, some cosmetics, etc. This article discusses the most common, and critical, endocrine disruptors that are easy to limit in today’s lifestyles.
Soybeans and soy-based products are the most notable source of phytoestrogens. There is much debate as to whether soy is a health food or harmful to hormonal health. Like most things, the answer is complicated and may depend on variables like age, gender, health status, amount and type consumed, and even the composition of the gut flora.
Evidence has documented that soy can alter steroid hormone production and transport by up-regulating sex hormone binding globulin (SHBG) and displacing estrogen and testosterone previously bound to SHBG. Additionally, in animal models, compounds found in soy have been shown to disrupt hormone-related processes. In the U.S., 80% of the soybeans grown are treated with glyphosate, a known xenoestrogen. Consequently, there may be an combined effect between the compounds in soy and glyphosate, potentially further promoting harmful estrogenic activity in humans.
While we cannot ignore the studies that have revealed the positive effects of soy, such as a reduction in coronary artery disease and breast and prostate cancers, many choose to limit soy intake or eliminate it completely due to mixed results and potential negative consequences. This can be challenging since soy is not only found in soybeans, soy milk and tofu, but is also found in nearly 60% of all other processed foods. Also, it is important to note that fermented forms of soy, like miso, natto, or tempeh, may not fall under the same considerations, as they contain a lower concentration of isoflavones (compound found in soy).
Conventionally produced dairy
Estrogens are one of the most concentrated hormones found in cow’s milk and other bovine dairy products, along with other hormones like progesterone and testosterone. It is estimated that 60-80% of estrogens found in the Western diet come from conventionally produced dairy products. Conventionally produced dairy include those dairy products derived from animals fed a mixed ration and no access to pasture, as opposed to organic dairy products from cows getting one-third of their energy from fresh pasture. Since the endocrine system is very sensitive, this source of exogenous (external) estrogens is likely to disrupt the endogenous (internal) hormonal balance, especially with higher consumption of conventionally produced dairy products.
Conventionally grown meat
In order to promote growth in conventionally grown livestock, antibiotics and growth hormones may often be used. In cattle, treating with exogenous estrogen (aka from an external source) may ensure optimal growth but can increase estrogen levels in the animal by 2-7 times, with peak levels found in the liver and fat tissue. There is ongoing debate on how the use of these compounds in conventionally grown livestock, meant for consumption, might impact human health. Though there may be a handful of confounding variables, there remains some evidence demonstrating elevated serum levels of estrogen in people who consume meat as compared to vegetarians.
While research and consensus are currently lacking, organic, grass-fed animal products may be preferable by those who consume meat and meat products, especially in those who seek to limit their exposure to exogenous hormones.
Even small amounts of alcohol have been shown to increase estrogen levels in premenopausal women, especially in the middle of their menstrual cycle. Similar results have been seen in men as well, with high levels of alcohol intake associated with signs of increased estrogen. According to research, alcohol works at the genetic level to up-regulate specific estrogen receptor activity and increase estrogen responsiveness. Furthermore, wine, beer, and spirits like bourbon, have been found to contain phytoestrogens, similar to soy, which we know have documented estrogenic activities in the body.
Food from plastic containers
Xenoestrogens, which are chemicals that mimic endogenous (internally made) estrogens, are not only found in industrial materials, but also in plastic wrap and food storage containers that may be in direct contact with the food we eat. Bisphenol A (BPA) may be the most widely known. BPA is a synthetic compound that is a plastic additive which is very much present in the modern world. Although air, dust, and water can be sources of BPA, the primary source of human exposure is through food and beverages. BPA leaches into food and liquids from the plastic coating inside of canned foods, plastic wrap, food storage containers, water bottles, and coffee cups. It has been well documented that BPA can activate estrogen receptors. It has also been found that BPA may be linked to other health issues like obesity.
Although there has been a large “BPA-free” social movement, many of the alternative materials being used have also been linked to the disruption in human hormones. Many other endocrine disruptors are present in the materials used to manufacture food and drink storage containers, like phthalates and styrene, which have also been shown to act as estrogenic compounds.
To minimize exposure of xenoestrogens:
- Invest in a glass or steel water bottle
- Use a non-plastic, reusable mug for coffee and tea
- If you must buy packaged food, choose foods in glass containers
- Never heat food in plastic
- Use BPA-free canned goods
In summary, many of the foods we consume and the products we come in contact with daily can negatively impact our endocrine system, especially when it comes to estrogen. Becoming aware of where endocrine disruptors may be hiding can help you stay more informed about your own hormonal health.
In healthy estrogen levels,
- Fucic A et al. Environmental exposure to xenoestrogens and oestrogen related cancers: reproductive system, breast, lung, kidney, pancreas, and brain. Environ Health. 2012;11(Suppl 1):S8.
- Fernandez SV et al. Estrogen and xenoestrogens in breast cancer. Toxicol Pathol. 2010;38(1):110-122.
- Patel S et al. Estrogen: The necessary evil for human health, and ways to tame it. Biomed Pharmacother. 2018;102:403-411.
- Whitten PL et al. Isoflavonoids. In: D’Mello JPF, editor. Handbook of Plant and Fungal Toxicants. Boca Raton: CRC Press; 1997;117–137.
- Patisaul HB et al. The pros and cons of phytoestrogens. Front Neuroendocrinol. 2010;31(4):400-419.
- Darbre PD. Environmental oestrogens, cosmetics and breast cancer. Best Practice & Research. Clin Endocrinol & Metabolism. 2006;20(1):121–143.
- Adlercreutz H et al. Dietary phytoestrogens and cancer: in vitro and in vivo studies. J Steroid Biochem Mol Biol. 1992;41:331–337.
- Dechaud H et al. Xenoestrogen interaction with human sex hormone-binding globulin (hSHBG).Steroids. 1999;64:328–334.
- Thongprakaisang S et al. Glyphosate induces human breast cancer cells growth via estrogen receptors. Food Chem Toxicol. 2013;59:129-136.
- Hutchins A, Slavin J, Lampe J. Urinary isoflavonoid phytoestrogen and lignan excretion after consumption of fermented and unfermented soy products. Journal of the American Dietetic Association. 1995;95(5):545-551.
- Malekinejad H et al. Hormones in dairy foods and their impact on public health – a narrative review article. Iran J Public Heal. 2015;44(6);742-758.
- Remesar X et al. Estrone in food: a factor influencing the development of obesity? Eur J Nutr. 1999;38 (5):247–253.
- Tunick M, et al. Case study: Differences in milk characteristics between a cow herd transitioning to organic versus milk from a conventional dairy herd. International Journal of Dairy Technology. 2015;68:511-518.
- Jeon SH et al. Risk assessment of growth hormones and antimicrobial residues in meat. Toxicol Res. 2010;26(4):301-313.
- Paris A et al. Hormones and growth promoters in animal production: from physiology to risk assessment. INRA Prod. Anim.2006;19:149–240. Translated to English.
- Aubertin-Leheudre M et al. Diets and hormonal levels in postmenopausal women with or without breast cancer. Nutr Cancer. 2011;63:514–524.
- Karelis AD et al. Comparison of sex hormonal and metabolic profiles between omnivores and vegetarians in pre- and post-menopausal women. Br J Nutr. 2010;104:222–226.
- Coutelle C et al. Risk factors in alcohol associated breast cancer: alcohol dehydrogenase polymorphism and estrogens. Int J Oncol. 2004;25(4):1127-1132.
- Gavaler JS. Alcoholic beverages as a source of estrogens. Alcohol Health Res World. 1998;22(3):220-227.
- Fan S, Meng Q, Gao B, Grossman J, Yadegari M, Goldberg I, and Rosen E. Advances in Brief Alcohol Stimulates Estrogen Receptor Signaling in Human Breast Cancer Cell Lines. Cancer Research. 2000;60:5635-5639.
- Gavaler J. Alcoholic beverages as a source of estrogens. Alcohol Health Res World. 1998;22(3):220-7.
- Słomczyńska M. Xenoestrogens: mechanisms of action and some detection studies. Pol J Vet Sci. 2008;11(3):263-269.
- Bisphenol A (BPA). Accessed from: https://www.niehs.nih.gov/health/topics/agents/sya-bpa/.
- Huo X et al. Bisphenol-A and Female Infertility: A Possible Role of Gene-Environment Interactions. Int J Environ Res Public Health. 2015;12(9):11101–11116.
- Vinas R et al. Bisphenol S disrupts estradiol-induced nongenomic signaling in a rat pituitary cell line: effects on cell functions. Envior Health Perspect. 2013;121(3):352-358.
- Andersen HR et al. Comparison of short-term estrogenicity tests for identification of hormone-disrupting chemicals. Environ Health Perspect. 1999;107(Suppl 1):89–108.
Photo credit: Knix