Breaking the link between obesity and cancer

Sally von Bargen once described herself as a “jolly, overweight, grandmother type” who watched her mother struggle with breast cancer and her father battle heart disease and diabetes. Overweight since childhood, she knew she was on a slippery slope toward weight-related illnesses, including cancer.

Then last year, she signed up for a Hutchinson Center study led by Dr. Anne McTiernan examining diet and exercise in overweight postmenopausal women.

For the scientifically rigorous study, von Bargen’s calorie intake was scrutinized, her movements meticulously recorded, her body fat and bone density carefully scanned. Her study goal was to lose 23 pounds. She lost 75, nearly one-third of her body weight.

“I can say—unequivocally—that I will never gain that weight back again because now I know how to exercise and eat to be healthy,” she said.

Von Bargen’s transformation illustrates how Hutchinson Center researchers, like McTiernan and her colleague Dr. Mario Kratz, are at the forefront of understanding—and potentially defusing—what is becoming a new cancer epidemic. Being overweight or inactive is known to increase a person’s risk of some of the most common cancers, including colorectal cancer, breast cancer and certain prostate cancers, and is also linked to cancers of the esophagus, pancreas, kidney and gallbladder.

The threat is so severe that McTiernan, whose numerous groundbreaking studies over the last 20 years have illuminated much of what we now know about obesity and cancer risk, likens obesity to another insidious problem that took decades to diminish.

“Obesity is almost like the new smoking,” McTiernan told the Los Angeles Times. “The effect isn’t as big for most cancers, but it’s so prevalent that it will have a huge impact.”

McTiernan’s research measures how exercise and weight loss affect the levels of estrogen, inflammation and other so-called “biomarkers” linked to cancer. Her studies have found that people who get regular, moderate exercise—even later in life—can reduce their risk for breast cancer, colon cancer, diabetes and other major diseases. This year alone, she published findings from several studies that explain how weight loss can reduce breast cancer risk and describe evidence-based factors that contribute to successful weight loss.

Kratz has also made significant strides with some of the world’s most innovative feeding studies, which he believes will redefine the guidelines of what we should and shouldn’t eat to reduce our cancer risk. His research focuses on inflammation, one of the big keys in the obesity-cancer equation.

Obesity, he explains, puts the body in a state of constant, low-grade inflammation, which can cause progressive damage linked to a variety of health problems, including cancer, heart disease and diabetes.

A current study investigates how sweetened beverages, such as soda with high-fructose corn syrup, impact levels of C-reactive protein (CRP) in a person’s blood, which signals the presence of inflammation.

“Our pilot studies showed that some sweeteners could cause a significant increase in a person’s CRP levels in just over a week,” Kratz said. “If that happens in eight days, imagine what it does over your entire life—it could have a substantial impact on your risk of developing many kinds of chronic disease.”

Kratz’s studies could ultimately reshape dietary guidelines to reflect new knowledge about which foods affect cancer risk. It’s all part of stopping obesity-related cancers before they strike.

The cancer prevention research of Drs. Anne McTiernan and Mario Kratz is supported by the Hutchinson Center's President’s Circle, a group of individuals and corporate benefactors whose aggregate funding speeds the development of innovations in all areas of our research.