The Centers for Disease Control and Prevention estimates around 35 percent of American adults are obese, meaning they have a body mass index higher than 30. Obesity is the leading cause of preventable death and contributes to health problems such as diabetes and heart disease. Certain hormones are a contributing factor to obesity, and estrogen appears to help determine your body fat distribution.
Estrogen is a sex hormone commonly associated with women -- though men also produce estrogen -- and is essential for reproductive and sexual development. Women produce estrogen in their ovaries, while men manufacture estrogen in the testes. Adrenal glands and fat cells also produce estrogen. The placenta of a pregnant woman makes estrogen. Estrogen levels typically decline as you age, especially for postmenopausal women.
Where you carry your body fat is an important factor in some health conditions. Decreasing levels of estrogen cause you to retain more weight around the abdomen, according to State Government of Victoria Australia's Better Health Channel. Abdominal fat may cause metabolic disruption and increase the risk of Type 2 diabetes, cancer and cardiovascular disease, particularly in women, states "Harvard Women's Health Watch," a publication of Harvard Medical School.
Estrogen Production and Weight Gain
Estrogen receptors in the brain appear to help control energy expenditure and food intake. Professor Deborah J. Clegg, of University of Cincinnati Academic Health Center, presented a study to the 234th American Chemical Society that showed how destroying estrogen receptors in the hypothalamus of rats caused them to eat more and gain extra weight. Clegg's research suggests estrogen reduction during menopause causes weight gain in women. Conversely, a study dating back to the April 1979 issue of "Journal of Clinical Endocrinology and Metabolism" found obese men with defective estrogen receptors actually produced more estrogen.
Estrogen, Obesity and Cancer
One theory suggests that breast and endometrial cancer is linked to the overproduction of estrogen. Since fat cells also produce estrogen, obesity appears to increase the risk of breast cancer. According to the National Cancer Institute, postmenopausal women would normally have lower estrogen levels, but obese postmenopausal women maintain higher levels than their slimmer counterparts, which might stimulate the growth of breast cancer after menopause. Obese women of any age are two to four times more likely to get endometrial cancer than normal-weight women, partially because of higher levels of estrogen.
Tackling Tummy Fat
"Harvard Women's Health Watch" reports you can control abdominal weight gain with moderate-intensity exercise for 30 to 60 minutes daily, and also cites a study by University of Pennsylvania that determined two hours of strength training weekly helped reduce and keep off belly fat. Postmenopausal women taking estrogen replacements have lower levels of abdominal fat accumulation, but hormone replacement therapy could increase your risks for heart attack, blood clots and breast cancer, according to Medline Plus.