Body fat is linked to six types of cancers

Among 10 recommendations to lower risk, a report calls on people to lose the extra pounds, especially around the waist.
Los Angeles Times .October 31, 2007
WASHINGTON -- Excess body fat increases an individual's risk for six types of cancer, according to a report to be released today by two leading cancer research groups.

The American Institute for Cancer Research and the World Cancer Research Fund offer 10 recommendations for cancer prevention, including limiting consumption of red meat and alcohol, avoiding processed meats and -- most importantly -- shedding those extra pounds.

The report, the second by the two nonprofit organizations, calls on people to "be as lean as possible within the normal range of body weight" as determined by the World Health Organization or national governments, and avoid weight gain and increases in waist circumference during adulthood.

"The recommendation reflects what science is telling us today: Even small amounts of excess body fat, especially if carried at the waist, increase risk," said W. Philip T. James, chairman of the London-based International Obesity Task Force and one of the 21 members on an international panel that prepared the report.

Increased body fat, particularly in the abdominal area, affects levels of hormones and growth factors, which can influence the development of cancer cells. In addition, the report says, obesity is characterized by "a low-grade chronic inflammatory state" in the body that can promote cancer.

In their first report a decade ago, the groups linked excess weight only to cancer of the endometrium, or uterine lining. Today's report, which took five years to prepare, reviewed more than 7,000 studies published worldwide. It said it found a convincing connection between excess fat and cancers of the esophagus, pancreas, colon and rectum, endometrium and kidney, along with breast cancer in post-menopausal women.

James called the link between body fat and six types of cancers "the most striking finding" of the analysis. "That is why body weight is the focus of our first recommendation," he said.

Two recommendations focusing on weight control -- being physically active for at least 30 minutes a day and eating sparingly or completely avoiding fast food, sugary sodas and processed foods low in fiber or high in sugar or fat -- are followed by seven other healthful tips.

Among them is eating more fruits and vegetables; the report says that "people who eat various forms of vegetarian diets are at low risk of some diseases, including some cancers." Also recommended were limiting red meat consumption to 18 ounces a week and, except for very rare occasions, avoiding processed meats -- cured, smoked, salted or chemically preserved products such as ham, bacon and hot dogs.

Once an individual reaches the 18-ounce weekly limit for red meat, every additional 1.7 ounces consumed a day increases cancer risk by 15%, the report said. Every 1.7 ounces of processed meat consumed a day increases cancer risk by 21%, it added.

Alcoholic beverages are a factor in cancers of the mouth, pharynx, larynx, esophagus, colon and liver, the report says, urging that consumption be limited to two drinks a day for men and one for women.

"It doesn't matter whether you are talking about wine, beer or spirits. When it comes to cancer, even small amounts of alcohol raise your risk," James said.

The remaining recommendations include limiting salt intake and getting necessary vitamins and minerals through nourishing foods, rather than dietary supplements.

Colleen Doyle, the American Cancer Society's director of nutrition and physical activity, says the report confirms everything her organization has been promoting.

"Weight, dietary habits and physical activity have a direct effect on cancer risk," she said.

"It is important to note this means people do have a significant amount of control over their risk of developing many types of cancer," she added. "Lifestyle changes can indeed make a difference."

The 517-page report is available at

Excess body fat, red and processed meats, alcohol raise cancer risk: expert panel

WASHINGTON - Many kinds of cancer could be prevented with simple lifestyle choices, says a comprehensive new report, which recommends keeping a lean body weight, limiting red meat consumption and ditching processed foods like bacon, hot dogs and luncheon meats except for the odd special occasion.

The 517-page report, released Wednesday by the American Institute for Cancer Research and the World Cancer Research Fund, says there is also convincing evidence linking consumption of alcohol to elevated cancer risk.

But the report by the groups' expert panel - its second in 10 years - aimed its prevention guns at excess body fat as a prime contributor to numerous forms of malignancies, including cancer of the esophagus, pancreas, colon, kidney and uterus, as well as breast cancer in post-menopausal women.

U.K. expert panel member Dr. Philip James told a Washington news conference that reducing average weight on a population basis could slash the number of new cancers worldwide by a third.

"And it's not just a question of simply being fat," he said in a message to individuals. "The evidence that has accumulated is that it's best to be as lean as possible."

James, who established the International Obesity Task Force, said people should aim to be near the bottom of the range that constitutes a healthy body mass index, or BMI.

Regular physical activity - which could be as simple as working up to an hour of brisk walking each day - can help take off pounds as well as cut the risk of several cancers in and of itself, he said.

Dr. Walter Willett, a professor of medicine at the Harvard School of Public Health, said obesity is nipping at the heels of cigarette smoking as the leading cause of preventable cancer.

"We are making progress and need to maintain reduced smoking," Willett said. "Now overweight and obesity are going up. So it will not be too far in the future that overweight and obesity will become the Number 1 cause of cancer."

The report also called on consumers to trim red meats like beef, pork and lamb from their diets to prevent colorectal cancer, saying that intake should be limited to about 500 grams of cooked meat per week. That's the equivalent of six 85-gram portions, each about the size of a deck of cards.

Scientific evidence suggests that every 48 grams of red meat consumed each day beyond the 500-gram weekly allotment increases cancer risk by 15 per cent, compared to someone eating no extra beef, pork or lamb.

But the panel was even more pointed in its recommendations about processed foods as culprits in increased cancer risk. Evidence shows "there is no safe level of consumption" for smoked, cured or salted products such as bacon, ham, sausage and luncheon meats.

"That's why we recommend that if people eat processed meat at all, they save it for special occasions like ham at Christmas or the occasional hot dog at a baseball game," James said.

The meat-limiting message brought a swift reaction from producers.

Lisa Mina, a spokeswoman for Canada's Beef Information Centre, said studies have shown that beef has 14 nutrients essential to good health and is part of Canada's Revised Guide to Healthy Eating. She said Canadians on average already eat less than the amount recommended by the expert panel.

"There is no convincing scientific evidence that consuming red meat, as part of a healthy balanced diet, increases the risk of cancer," the Beef Information Centre, Canadian Pork Council and the Canadian Meat Council said in a joint release. "Cancer is a complex disease with many contributing factors, including physical activity, obesity, smoking, alcohol consumption, diet, as well as family history and age."

The American Meat Institute (AMI) echoed that view, calling the report's conclusions "extreme and unfounded."

"Processed meats that contain nitrate (a preservative) are safe and sodium nitrate is an essential ingredient whose safety is without question," Randy Huffman, AMI Foundation vice-president of scientific affairs, said in a statement.

But the Canadian Cancer Society lauded the report's findings and recommendations.

"What this report is telling us today is that the evidence is more and more convincing about how we live, what we eat and our individual risk of cancer, that there is a role for individuals to reduce their risk of cancer," said Heather Logan, the society's director of cancer control policy.

"Certainly our perspective in looking at the key recommendations from this report is that less is more."

The expert panel also found convincing evidence that alcohol consumption is linked to cancer of the mouth, pharynx, larynx and esophagus, and is implicated in colorectal cancer among men and the probable cause of liver cancer and colorectal cancer in women.

"It doesn't matter whether you are talking about wine, beer or spirits, when it comes to cancer, even small amounts of alcohol raise your risk," James said. "In light of evidence suggesting that small amounts of alcohol protect against heart disease, however, the panel decided to recommend limiting rather than avoiding consumption."

The report advises keeping consumption to no more than two drinks a day for men and one drink daily for women.

The report, entitled Food, Nutrition, Physical Activity and the Prevention of Cancer: a Global Perspective, is the most comprehensive ever published on the evidence linking cancer risk to diet, physical activity and weight. It is the culmination of a five-year process that involved nine independent teams of scientists from around the world, hundreds of peer reviewers and 21 international experts who reviewed and analyzed more than 7,000 large-scale studies.