Study finds moderate weight loss reduces levels of sex hormones linked to breast cancer risk
Even a moderate amount of weight loss can significantly reduce levels of circulating estrogens that are associated with an increased risk of breast cancer, according to a study by researchers at Fred Hutchinson Cancer Research Center the first randomized, controlled clinical trial to test the effects of weight loss on sex hormones in overweight and obese postmenopausal women, a group at elevated risk for breast cancer.
The findings by Anne McTiernan, M.D., Ph.D., and colleagues are published online ahead of the May 21 issue of the Journal of Clinical Oncology, a publication of the American Society of Clinical Oncology.
"Based on previous research, our results suggest that losing just 5 percent or more of one's weight could cut by a quarter to a half the risk for the most common, estrogen-sensitive breast cancers," said McTiernan, director of the Hutchinson Center's Prevention Center and a member of its Public Health Sciences Division. McTiernan cautions that these findings only apply to overweight or obese women who are not taking hormone-replacement therapy.
Epidemiologists have long noted a link between obesity and increased risk of postmenopausal breast cancer. A relationship between body fat and estrogen production is thought to contribute to this risk.
The study was based on data from 439 overweight-to-obese, sedentary, Seattle-area women, ages 50 to 75, who were randomly assigned to one of four groups: exercise only (mainly brisk walking), diet only, exercise plus diet and no intervention. At the end of the study, participants on the diet-only and diet-plus-exercise arms lost an average of 10 percent of their starting weight, which was the goal of the intervention.
The study measured the effects of diet- and exercise-related weight loss on blood levels of several types of sex hormones, including three forms of estrogen (estrone, estradiol and free estradiol); two types of testosterone (total testosterone and free testosterone); a steroid necessary for the production of sex hormones (androstenedione) and sex hormone binding globulin, or SHBG, a protein that binds to sex hormones and therefore makes them less biologically active. High levels of SHBG are associated with reduced breast cancer risk. Free estradiol and free testosterone are forms of the hormones that are not bound to SHBG and therefore are more biologically active.
At the end of the study, the researchers found significant reductions in hormone levels among the women who received the dietary weight loss intervention, with the most striking results among those who both dieted and exercised:
- Estrone levels decreased 9.6 percent with diet and 11.1 percent with diet plus exercise.
- Estradiol levels decreased 16.2 percent with diet and 20.3 percent with diet plus exercise.
- Free-estradiol levels decreased 21.4 percent with diet and 26 percent with diet plus exercise.
- SHBG levels increased 22.4 percent with diet and 25.8 percent with diet plus exercise.
- Free-testosterone levels decreased 10 percent with diet and 15.6 percent with diet plus exercise.
"The amount of weight lost was key to changes in hormone levels," McTiernan said. "The biggest effect was through diet plus exercise; exercise by itself didn't produce much of a change in weight or estrogen." However, exercise has many important benefits for those on a weight-loss program, she noted. Exercise prevents loss of muscle and bone, and it helps keep off the weight long term. "I recommend women both diet and exercise, because in the long run that should help keep weight down and therefore keep estrogens down," she said.
This is the first study to show that losing weight through a healthy diet that included reducing calories, reducing fat and increasing vegetables, fruits and fiber significantly lowers blood estrogen levels in postemenopausal women, McTiernan said. "This shows that it's never too late to make lifestyle changes to reduce your risk for breast cancer."
The results of the study also could be relevant to overweight women who take breast cancer prevention drugs such as tamoxifen, raloxifene and exemestane, which either block the action of estrogen or stop its production. "None of these medications are recommended for use beyond about five years, and they can have significant side effects in some women. Therefore, women need long-term solutions for managing their risk," McTiernan said. "Weight loss represents an additional option for long-term breast cancer risk reduction without significant or bothersome side effects."
More information: Reduced-calorie Dietary Weight Loss, Exercise and Sex Hormones in Postmenopausal Women: Randomized Controlled Trial, Journal of Clinical Oncology.
Journal reference: Journal of Clinical Oncology
Provided by Fred Hutchinson Cancer Research Center
- Weight loss led to reduction in inflammation May 01, 2012 | not rated yet | 0
- Study finds diet plus exercise is more effective for weight loss than either method alone Apr 14, 2011 | not rated yet | 0
- High levels of estrogen associated with breast cancer recurrence Mar 06, 2008 | not rated yet | 0
- Dieting beats exercise for diabetes prevention, combination is best Aug 30, 2011 | not rated yet | 0
- Losing more than 15 percent of body weight significantly boosts vitamin D levels in overweight women May 25, 2011 | not rated yet | 0
- Motion perception revisited: High Phi effect challenges established motion perception assumptions Apr 23, 2013 | 3 / 5 (2) | 2
- Anything you can do I can do better: Neuromolecular foundations of the superiority illusion (Update) Apr 02, 2013 | 4.5 / 5 (11) | 5
- The visual system as economist: Neural resource allocation in visual adaptation Mar 30, 2013 | 5 / 5 (2) | 9
- Separate lives: Neuronal and organismal lifespans decoupled Mar 27, 2013 | 4.9 / 5 (8) | 0
- Sizing things up: The evolutionary neurobiology of scale invariance Feb 28, 2013 | 4.8 / 5 (10) | 14
How can there be a term called "intestinal metaplasia" of stomach
19 hours ago Hello everyone, Ok Stomach's normal epithelium is simple columnar, now in intestinal type of adenocarcinoma of stomach it undergoes "intestinal...
Pressure-volume curve: Elastic Recoil Pressure don't make sense
May 18, 2013 From pressure-volume curve of the lung and chest wall (attached photo), I don't understand why would the elastic recoil pressure of the lung is...
If you became brain-dead, would you want them to pull the plug?
May 17, 2013 I'd want the rest of me to stay alive. Sure it's a lousy way to live but it beats being all-the-way dead. Maybe if I make it 20 years they'll...
MRI bill question
May 15, 2013 Dear PFers, The hospital gave us a $12k bill for one MRI (head with contrast). The people I talked to at the hospital tell me that they do not...
Ratio of Hydrogen of Oxygen in Dessicated Animal Protein
May 13, 2013 As an experiment, for the past few months I've been consuming at least one portion of Jell-O or unflavored Knox gelatin per day. I'm 64, in very...
Alcohol and acetaminophen
May 13, 2013 Edit: sorry for the typo in the title , can't edit I looked around on google quite a bit and it's very hard to find precise information on the...
- More from Physics Forums - Medical Sciences
More news stories
The gap between life expectancy in patients with a mental illness and the general population has widened since 1985 and efforts to reduce this gap should focus on improving physical health, suggest researchers in a paper ...
Cancer 8 hours ago | not rated yet | 0
By studying the roles two proteins, thrombospondin-1 and prosaposin, play in discouraging cancer metastasis, a trans-Atlantic research team has identified a five-amino acid fragment of prosaposin that significantly reduces ...
Cancer 9 hours ago | not rated yet | 0
A novel transcriptome-based classification of colon cancer that improves the current disease stratification based on clinicopathological variables and common DNA markers is presented in a study published in PLOS Medicine this w ...
Cancer 9 hours ago | not rated yet | 0
A study of veterans at high risk for developing lung cancer shows that low-dose computed tomography (LDCT) can be highly effective in helping clinicians spot tiny lung nodules which, in a small number of patients, may indicate ...
Cancer 11 hours ago | not rated yet | 0
An attack on glioblastoma brain tumor cells that uses a modified poliovirus is showing encouraging results in an early study to establish the proper dose level, researchers at Duke Cancer Institute report.
Cancer 13 hours ago | not rated yet | 0
(Medical Xpress)—Native peoples in regions where cameras are uncommon sometimes react with caution when their picture is taken. The fear that something must have been stolen from them to create the photo ...
15 hours ago | 4.2 / 5 (5) | 0 |
(Medical Xpress)—Despite spending billions of dollars on research and development, drug companies have been unable to come up with effective treatments for dementia and Alzheimer's Disease (AD). Now, A. ...
13 hours ago | 4.9 / 5 (11) | 0 |
Australian scientists have charted the path of insulin action in cells in precise detail like never before. This provides a comprehensive blueprint for understanding what goes wrong in diabetes.
15 hours ago | 4.6 / 5 (7) | 0 |
An experimental sleeping pill from US drug company Merck is effective at helping people fall and stay asleep, according to reviewers at the US Food and Drug Administration, which could soon approve the new drug.
8 hours ago | 3 / 5 (2) | 0
Activating an enzyme known to play a role in the anti-aging benefits of calorie restriction delays the loss of brain cells and preserves cognitive function in mice, according to a study published in the May ...
9 hours ago | 5 / 5 (4) | 0 |
A drug commonly used to treat depression and anxiety may improve a stress-related heart condition in people with stable coronary heart disease, according to researchers at Duke Medicine.
10 hours ago | 5 / 5 (1) | 0 |