Obesity continues to rise in the US, exceeding 30 percent in most sex and age groups, according to an article published in "JAMA" in 2010. For females in particular, obesity creates the risk of estrogen dominance, or having an excessive amount of estrogen circulating in the body. High levels of estrogen are associated with increased cancer and diabetes risks.
Types of Estrogen
According to webmd.com, estrogen is actually made up of several different hormones: estradiol, estriol, and estrone. Estradiol is the primary hormone for women of childbearing age, and is important in sexual functioning and bone health. It is also often linked to gynecological disorders and cancer. Estriol is created by the placenta during childbirth, and estrone is the only estrogen to be present in the body after menopause. Men also have levels of estrogen, although they are supposed to be lower than in females. The website also discusses the fluctuations in estrogen levels throughout a lifetime, seeing higher levels during childbearing years and declining levels after menopause.
Estrogen Production
Originating with cholesterol, sex hormones are produced after a number of biochemical reactions. Body fat plays a large role in estrogen production, both too much and too little fat. Females with low amounts of body fat often have low sex hormone levels, states webmd.com, and can suffer from dysmenorrhea and fragile bone structure. Conversely, a high body mass index (BMI) can result in increases in estrogen levels. A study published in the "Journal of the American Academy of Dermatology" in 2001 stated that although estradiol is mostly produced from the ovaries, other sources include adipose, or fat, tissue.
Adipose and Estrogen
Adipose tissue is the technical term for fat deposits, which contains a substance called aromatase. Aromatase prompts the conversion of steroids to estrogen, according to the article in "Journal of the American Academy of Dermatology." It is also found in skin cells, and the article states that "aromatase expression in adipose tissue and possibly the skin primarily accounts for the extraglandular (peripheral) formation of estrogen and increases as a function of body weight and advancing age." Thus, increases in body fat can increase levels of estrogen.
Obesity, Estrogen, and Heart Disease
A 2009 article in the "Journal of Cardiovascular Translation Research" discussed the link between obesity, estrogen, and heart disease. According to this article, adipose tissue in the abdominal area poses a greater risk of heart disease than subcutaneous, or under the skin, fat. Because estrogen levels drop after menopause, women may develop more of an abdominal fat pad. Overall adiposity is typically controlled by certain areas of the brain, and is directly influenced by sex hormones. Thus, the article concluded that "differences in cardiovascular disease may be under the influence of sex hormones either directly in the brain or through their influence of body fat distribution."
Risks of Obesity and High Estrogen
Although it has not been brought to the public's general attention until more recently, the link between estrogen and obesity has been studied for over 20 years. An article published in 1987 in the "American Journal of Clinical Nutrition" states that obesity causes alterations in the metabolism, or breakdown, of estrogens in the body, which can lead to substances that retain estrogenic properties. Because these substances still possess estrogen qualities, the tissues receive more estrogen stimulation than is normal. The "European Journal of Cancer Prevention" published an article this year listing the consequences of unopposed estrogen stimulation. Obesity, type 2 diabetes, uterine overgrowth, prostatic enlargement, prostate cancer and breast cancer are among the concerns, as are anxiety, depression, heart disease and stroke.
References
- "JAMA"; Prevalence and Trends in Obesity Among US Adults, 1999-2008; Flegal, M et al; January 2010
- WebMD Website, Estrogen Levels in Females
- "Journal of the American Academy of Dermatology"; Estrogen production and action; Nelson LR and Bulun SE; September 2001
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