Diet, exercise offer protection against cancer

FILE - In this June 26, 2012 file photo, two women speak to each other in New York. A national telephone survey found 13 states with very high rates of obesity. A national telephone survey found 13 states with very high rates of obesity in 2012. But overall, the proportion of Americans deemed obese has been about the same for years now. Results were made available by the Centers for Disease Control and Prevention. "A plateau is better than rising numbers. But it's discouraging because we're plateauing at a very high number," said Kelly Brownell, a Duke University public policy expert who specializes in obesity. (AP Photo/Mark Lennihan)

FILE - In this June 26, 2012 file photo, two women speak to each other in New York. A national telephone survey found 13 states with very high rates of obesity. A national telephone survey found 13 states with very high rates of obesity in 2012. But overall, the proportion of Americans deemed obese has been about the same for years now. Results were made available by the Centers for Disease Control and Prevention. "A plateau is better than rising numbers. But it's discouraging because we're plateauing at a very high number," said Kelly Brownell, a Duke University public policy expert who specializes in obesity. (AP Photo/Mark Lennihan)

Published Apr 11, 2014

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Washington - Cutting your risk of cancer is no longer just about shunning tobacco. Be lean. Eat healthfully. Get active. Common-sense lifestyle strategies for lowering the risk of heart disease and diabetes are now being shown to help prevent many types of cancer.

Of course, there are few absolutes in cancer prevention. Cancer is still a riddle, with many factors, including genetics, playing a role. But growing evidence suggests that there are steps that we can take to lower our chances of getting the disease.

Otis Brawley, chief medical officer for the American Cancer Society (ACS), urges careful attention to the “three-legged stool” of excess weight, poor diet and inadequate physical activity, which together are linked to between a quarter and a third of cancer cases.

If tobacco use continues its decline of the past 15 years, he said, that trio might supplant smoking as the leading preventable cause of cancer.

A recent study found that women who followed the ACS Guidelines on Nutrition and Physical Activity for Cancer Prevention lowered their risk significantly. Those guidelines include maintaining a healthy weight, adopting a physically active lifestyle, consuming a healthful diet that emphasises plant-based food, and limiting alcohol intake. Data on more than 65 000 post-menopausal women tracked for more than 12 years found that women who followed the guidelines most closely had a 17 percent lower risk of any cancer, a 22 percent lower risk of breast cancer and a 52 percent lower risk of colorectal cancer, according to a study released in January.

The women who best adhered to the guidelines were also 27 percent less likely to have died during the time frame of the study.

 

ACS guidelines include:

1. Maintain a healthy weight

 

Being as lean as possible and maintaining a healthy weight are the key components of cancer prevention. People should aim for a body mass index (BMI) score of 18.5 to 24.9.

“The data is becoming more consistent that gaining excess weight as we age, and even children being very heavy, can increase risks for cancers later in life,” said Rachel Ballard-Barbash of the National Cancer Institute.

According to the institute, extra body weight is associated with greater risk of cancers of the breast, colon and rectum, endometrium, esophagus, kidney and pancreas. Added weight also probably raises the risk of cancers such as gallbladder, liver, non-Hodgkin lymphoma, multiple myeloma, cervix, ovary and prostate.

 

 

2. Get active.

Your level of physical activity may affect your risk of several kinds of cancers: breast, colon, endometrium and prostate.

Ballard-Barbash said a sedentary lifestyle, coupled with overeating, could create an energy imbalance that causes abnormalities in the body. If you take in more calories than you burn, this imbalance can spur metabolic and hormonal changes and inflammation that may fuel many diseases, including cancer, heart disease and diabetes. She said people who developed cancers such as colon, breast, lung and prostate often had other diseases as well, because some of the same mechanisms affected all these diseases.

 

Research in this area is growing. For example, post-menopausal women who walk seven hours a week have a 14 percent lower risk of developing breast cancer compared with those who walk less than three hours a week, according to an October study.

The ACS recommends at least 150 minutes of moderate-intensity aerobic activity such as brisk walking or 75 minutes of jogging weekly.

 

 

3. Eat healthfully.

 

For preventing disease, the trend was to think about the entire diet or dietary patterns, rather than the particulars of foods or nutrients, Ballard-Barbash said.

“We don’t know of a diet that definitely will prevent cancer,” said Moshe Shike, a cancer prevention expert at Memorial Sloan Kettering Cancer Center in New York.

“But we have very strong evidence that a healthy diet can reduce the risk of certain cancers and (that) unhealthy diet and obesity are associated with increased risk.”

The ACS recommends a diet rich in plants and whole-grain foods, especially one that controls calories consumed. The timing of your meals could jump-start your metabolism and helped you balance your energy and burnt calories efficiently, said Ballard-Barbash. She noted that studies suggested that eating your evening meal earlier and redistributing calories throughout the day, as opposed to eating later in the evening, might help reduce how many calories you ate and how well your body burnt those calories.

Shike and others recommend a diet rich in fruits and vegetables, with little red meat and more fish, whole grains and nuts. Study author Cynthia Thomson says half your dinner plate should consist of plant-based foods.

Cancer prevention experts also advise avoiding tobacco, limiting alcohol, knowing your family history, being careful about sun exposure and getting age-appropriate screening.

They also suggest getting vaccinated against two major cancer-causing viruses: hepatitis B virus, linked to liver cancer, and human papillomavirus, which is linked to cervical and throat cancers.

In acknowledging that cancer is not completely preventable, many experts use driving metaphors to explain managing the risk.

“We will wear seat belts. Most of the time we don’t need them,” said Edward Giovannucci, a professor of nutrition and epidemiology at the Harvard School of Public Health. “But most people think it’s worth putting on seat belts. It makes sense to follow these guidelines.”

“It’s about starting from today moving forward,” said Shike. “You can’t change the past. But you can do things to improve your chances and decrease your risk.” – Washington Post

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