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Obesity is Linked to an Increased Risk of Developing Cancer

(HealthDay News/Dr. Tango) -- Weight management, exercise, and proper nutrition are key to reducing the risk of developing cancer. The earlier in life these habits are adopted, the greater the benefits will be according to a new study.

Factors such as birth weight, childbearing, breastfeeding and adult height and weight also influence the risk of developing cancer, according to a report published by the American Institute for Cancer Research and the Britain-based World Cancer Research Fund.

Obesity is Linked to an Increased Risk of Developing Cancer

Understanding how these factors affect the risk of developing cancer, and how to use this information in the prevention of this disease offers promising new directions for cancer research, pointed out the authors of the study.

"We need to think about cancer as the product of many long-term influences and not as something that just happens", said Dr. Walter J. Willett, professor of epidemiology and nutrition at the Harvard School of Public Health and one of the authors of the study, Food, Nutrition, Physical Activity, and the Prevention of Cancer: A Global Perspective.

The report, an analysis done by scientists from around the world on more than 7,000 studies, offers 10 recommendations to help prevent cancer. They include maintaining a healthy weight, exercising at least 30 minutes a day, limiting the intake of red meat and alcohol and avoiding processed meats.

"These findings are right on,” said Colleen Doyle, director of nutrition and physical activity at the American Cancer Society. "They are consistent with our own nutrition and physical activity guidelines. They clearly put the emphasis where it needs to be and that's on weight control.”

"This report brings good news,” added Karen Collins, a nutrition advisor at the American Institute for Cancer Research. "If we watch our weight, make exercise a part of our daily routine, and follow a healthy and balanced diet, we could prevent a third of cancers from occurring,” she explained. "Extra weight is not dead weight,” she explained. "It's an active metabolic tissue that produces substances that promote the development of cancer."

"People should consider this message empowering,” Collins said.

The analysis of the studies found a definite link between excess fat and cancers of the esophagus, pancreas, colon and rectum, endometrium, kidney as well as breast cancer in postmenopausal women.

According to the report, the risk of excess weight begins at birth. The link between birth weight and breast cancer has to do with body fat. Excess body fat influences the body's hormones, and these changes can make it more likely for cells to undergo the kind of abnormal growth that leads to cancer, the researchers affirmed.

In addition, overweight girls can start menstruating at an earlier age. Therefore, over their lifetime, they will have more menstrual cycles. The report found that this extended exposure to estrogen is associated with an increased risk of premenopausal breast cancer.

Not smoking is the most important thing a person can do to reduce the risk of cancer, said Doyle. However, she added, "there are estimations that obesity will surpass smoking as the leading preventable cause of death."

"It's wonderful to see another report emphasize that being active, controlling your weight and following a healthy diet are going to help you reduce your risk of not only cancer but heart disease and diabetes as well," added Doyle.

The report also found that breastfeeding can lower a mother's risk for developing breast cancer. In addition, infants who are breastfed are at a lower risk of becoming overweight or obese, and this also means a lower risk of developing cancer.

"There exists strong evidence to back up breastfeeding and the fact that it offers cancer protection to both mothers and their children makes it one of the 10 recommendations to prevent cancer," said Willett.

In addition, tall people seem to be at a higher risk of colorectal and postmenopausal breast cancer, according to the report.

"We found that height is also probably linked to an increased risk of ovarian, pancreatic and premenopausal cancer," added Willett. Although the link between height and cancer is convincing, tall people are not destined to suffer from cancer, he assured.

Willett noted that being at an increased risk does not guarantee you will develop cancer. "Risk isn't fate,” he said. "Evidence clearly shows that risks can be modified."

"We wanted to point out these emerging relationships because we think they are more important than what the scientific community and the public believe," added Willett. "Whether we develop cancer or not has to do with our genes and with the choices we make everyday. Our risk of cancer is also influenced by our experiences accumulated throughout life starting from the moment of conception."

Body weight and composition are important factors, said one expert.

"This report really reinforces the connection between being overweight or obese and the increased risk of many, if not all, cancers,” said Carolyn Lammersfeld, national director of nutrition at Cancer Treatment Centers of America. "The majority of Americans are not aware of that connection. They are more concerned with pesticides and environmental pollutants, however obesity is a much greater risk factor,” she affirmed.

However, risks can be minimized, she added. "If you don't have cancer, it's never too late to try to do what you can to lower your risk,” Lammersfeld said. "In addition, cancer survivors should follow diet and weight recommendations to prevent cancer from reoccurring.”

The report pointed out that people should not use dietary supplements to try to offset cancer risk which is something Lammersfeld agreed with. "You can't fix a crappy diet with supplements,” she said.

More information

To read the full report, visit the American Institute for Cancer Research .


Article written by HealthDay, translated by Dr. Tango

SOURCES: Food, Nutrition, Physical Activity, and the Prevention of Cancer: A Global Perspective, American Institute for Cancer Research and World Cancer Research Fund, Oct. 31, 2007; Colleen Doyle, M.S., R.D., director, nutrition and physical activity, American Cancer Society, Atlanta; Carolyn Lammersfeld, M.A, national director of nutrition, Cancer Treatment Centers of America; Karen Collins, M.S., R.D., nutrition advisor, American Institute for Cancer Research © Author rights 2007, ScoutNews, LLC.

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