 |
|
Study: Exercise, diet may protect against colorectal cancer
May 16, 2006MADISON-Voluntary exercise and a restricted diet reduced the number and size of pre-cancerous polyps in the intestines of male mice and improved survival, according to a study by a University of Wisconsin-Madison research published May 13 in the journal Carcinogenesis.
The study is the first to suggest that a "negative energy balance"-produced by increasing the mice's energy output by use of a running wheel, while maintaining a restricted calorie intake-appeared to be the important factor in inhibiting the growth of polyps, which are the forerunners of colorectal tumors, says lead author Lisa H. Colbert, assistant professor in the UW-Madison department of kinesiology.
For the study, Colbert and her co-authors used mice with a genetic mutation that predisposed them to develop intestinal polyps.
"Our studies are relevant for humans in that these mice have a mutation in one of the same genes, APC, that is also mutated in human colon cancer," she explains. "The protective effect of exercise and lower body weight in our mice is consistent with epidemiological evidence in humans that suggests higher levels of activity and lower body weight reduces the risk of colon cancer."
Mutations in the APC gene in humans are responsible for an inherited condition called familial adenomatous polyposis (FAP). This condition affects about one in 10,000-15,000 people worldwide, and 95 percent of those affected develop polyps in the colon that eventually progress into cancer, usually before age 40.
The researchers randomly assigned seven-week-old male mice to either voluntary wheel running or to no exercise for 10 weeks.
Over the course of the study, the no-exercise control group consumed as much food and water as they wanted. For the first three weeks, the exercising mice received as much as those in the control group. After that, the active mice were restricted to the amount of food and water that the control group received the previous week, which resulted in a negative energy balance.
By the end of the 10 weeks, six of the 23 control mice had died due to the number of polyps that had grown and the resulting anaemia, while all 24 exercising mice were still alive.
"The exercising mice ran an average of 3.8 km a day, and the further they ran the fewer polyps they had. Exercise significantly reduced total polyp number and polyp size, as well as prolonging survival," says Colbert. "On average, there were 16 polyps per mouse in the exercising mice compared to 22 polyps in the control mice-a decrease of 25 percent."
Even though the exercising mice weighed less than those in the control group at the end of the study, they retained more body fat than the non-exercising mice, which Colbert attributes to the fact that the exercising mice were healthier than the non-exercising mice.
The researchers also found that the exercising mice had higher levels of insulin-like growth factor-1 (IGF-1) and corticosterone-hormones associated with the onset of cancer-but saw no correlation with a greater numbers of polyps. Colbert explains, "These data suggest that voluntary exercise that induces a negative energy balance protects against the onset of cancer in these mice, but that the mechanism is unlikely to be related to body composition, IGF-1 or corticosterone."
Another study published in this issue of Carcinogenesis found that exercise can protect against skin cancer.
In this study, female mice that had 24-hour access to running wheels and were exposed to ultraviolet B light (UVB) took longer to develop skin tumors, developed fewer and smaller tumors, and had decreased amounts of body fat compared to mice that did not have access to running wheels. The researchers emphasized that it was unknown yet whether exercise decreased the risk of sunlight-induced skin cancer in humans, and clinical trials were needed to investigate this further.
University of Wisconsin-Madison
"Our studies are relevant for humans in that these mice have a mutation in one of the same genes, APC, that is also mutated in human colon cancer," she explains. "The protective effect of exercise and lower body weight in our mice is consistent with epidemiological evidence in humans that suggests higher levels of activity and lower body weight reduces the risk of colon cancer."
Mutations in the APC gene in humans are responsible for an inherited condition called familial adenomatous polyposis (FAP). This condition affects about one in 10,000-15,000 people worldwide, and 95 percent of those affected develop polyps in the colon that eventually progress into cancer, usually before age 40.
The researchers randomly assigned seven-week-old male mice to either voluntary wheel running or to no exercise for 10 weeks.
Over the course of the study, the no-exercise control group consumed as much food and water as they wanted. For the first three weeks, the exercising mice received as much as those in the control group. After that, the active mice were restricted to the amount of food and water that the control group received the previous week, which resulted in a negative energy balance.
By the end of the 10 weeks, six of the 23 control mice had died due to the number of polyps that had grown and the resulting anaemia, while all 24 exercising mice were still alive.
"The exercising mice ran an average of 3.8 km a day, and the further they ran the fewer polyps they had. Exercise significantly reduced total polyp number and polyp size, as well as prolonging survival," says Colbert. "On average, there were 16 polyps per mouse in the exercising mice compared to 22 polyps in the control mice-a decrease of 25 percent."
Even though the exercising mice weighed less than those in the control group at the end of the study, they retained more body fat than the non-exercising mice, which Colbert attributes to the fact that the exercising mice were healthier than the non-exercising mice.
The researchers also found that the exercising mice had higher levels of insulin-like growth factor-1 (IGF-1) and corticosterone-hormones associated with the onset of cancer-but saw no correlation with a greater numbers of polyps. Colbert explains, "These data suggest that voluntary exercise that induces a negative energy balance protects against the onset of cancer in these mice, but that the mechanism is unlikely to be related to body composition, IGF-1 or corticosterone."
Another study published in this issue of Carcinogenesis found that exercise can protect against skin cancer.
In this study, female mice that had 24-hour access to running wheels and were exposed to ultraviolet B light (UVB) took longer to develop skin tumors, developed fewer and smaller tumors, and had decreased amounts of body fat compared to mice that did not have access to running wheels. The researchers emphasized that it was unknown yet whether exercise decreased the risk of sunlight-induced skin cancer in humans, and clinical trials were needed to investigate this further.
University of Wisconsin-Madison
Colorectal Cancer Current Events and Colorectal Cancer News RSSGenetic Engineering & Biotechnology News reports on growing role of molecular diagnostics
Novel platform technologies and key advances in genomics are rapidly driving the development of molecular diagnostics, reports Genetic Engineering and Biotechnology News (GEN).
New screening technologies improve detection of polyps during colonoscopy
Two studies presented at the American College of Gastroenterology's 73rd Annual Scientific Meeting in Orlando highlight new technologies with the potential to improve the detection of colorectal polyps and flat lesions during colonoscopy.
Metabolic syndrome ups colorectal cancer risk
In a large U.S. population-based study presented at the 73rd Annual Scientific Meeting of the American College of Gastroenterology, metabolic syndrome patients had a 75 percent higher risk of colorectal cancer compared to those without metabolic syndrome.
Study confirms colonoscopy associated with reduced colorectal cancer incidence
Patients who undergo a complete negative colonoscopy have a reduced incidence of colorectal cancer, confirms a study published in Clinical Gastroenterology and Hepatology.
Surgical treatment provides new option for some colorectal cancer patients
Research out of Wake Forest University School of Medicine suggests that a surgical technique not traditionally used in advanced abdominal cancer may be a viable treatment option for some patients previously thought to be untreatable, offering the real possibility of extending survival for those patients.
Black Americans Are At Greater Risk for Colon Polyps
Black Americans have a higher occurrence of colon polyps, according to a new study. This is a significant finding considering the incidence of colon cancer among black men has increased and remained unchanged among black women during the last 20 years.
Racial disparities decline for cancer in Missouri
Cancer death rates in the United States are highest among African Americans, but a new report shows that in Missouri the disparity in cancer incidence and death between African Americans and whites is declining.
Risk of colorectal cancer extremely low 5 years after a normal colonoscopy screening
A study appearing in the Sept. 18 issue of the New England Journal of Medicine shows that among individuals with no colorectal neoplasia (abnormal growths) on initial screening colonoscopy, the five-year risk of colorectal cancer is extremely low.
Severe stress more common among long-term cancer survivors
Long-term survivors of adult cancers are almost twice as likely to report psychological distress severe enough to cause moderate to serious problems functioning in social, work or school situations, compared to the general population.
Cancer-causing gut bacteria exposed
Normal gut bacteria are thought to be involved in colon cancer but the exact mechanisms have remained unknown. Now, scientists from the USA have discovered that a molecule produced by a common gut bacterium activates signalling pathways that are associated with cancer cells.
More Colorectal Cancer Current Events and Colorectal Cancer News Articles
 | Be a Survivor: Colorectal Cancer Treatment Guide (Be a Survivor) by Vladimir Lange Dr. Lange’s comprehensive overview of cancer and treatment options offers detailed information using simple, concise language and a wide variety of color photos and drawings. Colorectal cancer patients need to know more about their disease, yet there is an overload of information. Be a Survivor gives the patient the specific, reliable and necessary information to make good decisions about their... |
 | Positive Options for Colorectal Cancer: Self-Help and Treatment by Carol Ann Larson Colorectal cancer develops slowly over a period of several years, undetected, usually as polyps. It is a preventable and treatable disease if caught in time, yet most know little about how to read its symptoms. Written for the layperson, this book covers all the uncomfortable questions and answers about the disease, from prevention and warning signs, to screening and diagnosis techniques, to... |
 | Challenges in Colorectal Cancer The latest guidance on challenging and controversial aspects of colorectal cancer Colorectal cancer is one of the most common forms of cancer in the US and Europe. Thousands of people are diagnosed with the disease every year and nearly half of these die as a result. As colorectal cancer is curable when detected early, a significant proportion of these deaths could be prevented by earlier... |
 | The Intelligent Patient Guide to Colorectal Cancer: Information, risk, prevention, symptoms, signs, diagnosis, stage, surgery, radiation, chemotherapy, prognosis, treatment of/for colon rectal cancer. by Michael E. Pezim, David A. Owen The Intelligent Patient Guide book series was created in 1989 by a group of American and Canadian-trained physicians frustrated by the lack of quality information available for their cancer patients. The books became bestsellers, and their appeal has grown despite the development of the Internet. Whereas the Internet is an explosion of medical information that can confuse and intimidate, these... |
 | 100 Questions & Answers About Colorectal Cancer by Susannah ROse, W. Douglas Wong David S. Bub |
 | American Cancer Society's Complete Guide to Colorectal Caner by American Cancer Society Don't die of embarrassment--get informed about colorectal cancer Although colorectal cancer is the third most common cancer found in men and women, you may be unaware of your risk and don't know what you can do to prevent this serious disease. You may be too embarrassed to ask your doctor about changes in your bowel habits or get screened for colorectal cancer. American Cancer Society's Complete... |
 | Colorectal Cancer (Contemporary Issues in Cancer Imaging) Colorectal cancer is the second most common cause of cancer death in the developed world. The last five years have seen dramatic improvements in the multidisciplinary management of this malignancy. In this volume, experts at the forefront of these advances contribute their knowledge and experience on the major advances that have occurred in diagnosis, staging, preoperative and adjuvant therapy,... |
 | Management of Colorectal Cancer by Harry Bleiberg, Phillipe Rougier, Hans-Joachim Wilke Institut Jules Bordet, Brussels, Belgium. Global overview of current research. For oncologists and residents. Extensive references. 70 contributors, 8... |
 | What Your Doctor May Not Tell You About(TM) Colorectal Cancer: New Tests, New Treatments, New Hope (What Your Doctor May Not Tell You About...) by Mark Bennett Pochapin The latest edition in the bestselling What Your Doctor May Not Tell You series explodes the myths and misconceptions about the third most common-and second most deadly-form of cancer in the United States. Over 50,000 men and women die from colorectal cancer each year-a particularly alarming statistic since it is also one of the most preventable and treatable cancers. In fact, it is estimated that... |
| 100 Questions & Answers About Colorectal Cancer by David Bub, Susannah Rose, W. Douglas Wong This book is a patient-oriented guide to dealing with colorectal cancer. A question and answer format is used to cover many topics related to this... |
| © 2008 BrightSurf.com |