Exploring the Food-Cancer Connection
By Tara Hulen
Wendy Demark-Wahnefried, Ph.D., R.D.
• Connects the UAB Cancer Center’s basic nutrition science and lifestyle-intervention programs in a translational and interdisciplinary approach
• Conducted some of the largest studies on the links among diet, hormones, genes, and cancer progression; effective lifestyle interventions to improve cancer survivorship; and metabolic/body composition changes in response to cancer treatment
• Serves on boards and panels for the American Cancer Society, several National Institutes of Health standing and ad-hoc committees, and the World Cancer Fund
• Named a Komen Professor of Survivorship
• Holds an undergraduate degree in nutrition science and chemistry from the University of Michigan; a master’s in nutrition from Texas Woman’s University; and a doctorate in nutrition science from Syracuse University
The eye-opening, life-reassessing shock of a cancer diagnosis can also be one of life’s teachable moments. For two decades, that insight—finding hope in the midst of catastrophe—has driven the research of Wendy Demark-Wahnefried, Ph.D., R.D., the new associate director for cancer prevention and control at the UAB Comprehensive Cancer Center and Webb Chair in Nutrition Sciences at the UAB School of Health Professions. She is an international leader in understanding how dietary changes affect cancer survivorship.
Confronted with a diagnosis of cancer, many patients are open to diet and lifestyle changes that can help them get and stay healthy, says Demark-Wahnefried. “There’s a great opportunity in cancer survivorship, because more and more people are surviving their cancer, particularly for breast and prostate cancer, where more than 90 percent of people diagnosed are surviving. We’ve had good success in actually making people better than they were before they had cancer. There are lots of things that can be done.”
It’s especially important to take advantage of this opportunity, she continues, “because although people survive their cancer, they’re at more risk for having a second cancer once they’ve been diagnosed. They’re also at more risk for heart disease, osteoporosis, and other illnesses” due to weakened bodies, pre-existing conditions, genetic predisposition, and other factors.
Understanding the Chemotherapy-Weight Gain Dilemma
Cancer Center director Ed Partridge, M.D., recruited Demark-Wahnefried to UAB in spring 2010 after she had spent three years at M.D. Anderson Cancer Center in Houston, which followed a long research career at Duke University.
It was the chance to work with a renowned Duke researcher that drew Demark-Wahnefried into the field. She became involved in a major study investigating the reasons why women with breast cancer tend to gain weight while on chemotherapy.
This weight gain is a concern, Demark-Wahnefried explains, because 71 percent of breast cancer patients who are diagnosed after menopause are overweight or obese to begin with. And even though the exact nature of the relationship is still unclear, it is apparent that excess weight is harmful to women with breast cancer. “What’s theorized is that body weight affects hormonal levels,” Demark-Wahnefried says. “It also affects adipokines and cytokines, which are inflammatory biomarkers that probably feed the cancer.”
Before the study began, Demark-Wahnefried explains, the clichéd assumption went like this: Women were gaining weight because they indulged in extra comfort foods while dealing with the stresses of chemotherapy. But metabolic tests revealed that women actually eat less when they are on chemotherapy, she says. The culprit is the fatigue caused by chemotherapy, which leads women to become less active; that, in turn, brings about a loss of lean body mass. “When you lose lean body mass, it makes an impact,” Demark-Wahnefried says. “You can’t eat as many calories as you once did.”
The quantity of muscle mass lost was astonishing, she recalls. “The amount we saw just wasting away from these women in one year after diagnosis was comparable to 10 years of normal aging.” Chemotherapy targets quickly metabolizing cells, including muscle, she says, “so it makes sense.”
The Power of Flax
A new understanding of the relationship between nutrition and cancer is opening promising avenues of research, Demark-Wahnefried says. “We just completed a phase 2 trial for prostate cancer in which we tested ground flaxseed,” she says. “We found that we were able to slow the tumor proliferation rate, or how fast the tumor was dividing.”
Anyone interested in adding flaxseed to his or her diet should keep in mind that the seeds must be ground because they often aren’t digested whole—and small seeds can cause intestinal issues in some patients, notes Demark-Wahnefried. Flaxseed must be freshly ground and then refrigerated or frozen or it will turn rancid.
The study actually started out as an examination of omega-3 fatty acids from fish oil, Demark-Wahnefried says—but since people didn’t like taking fish oil in the amounts given, the researchers switched to ground flaxseed. (They didn’t study flaxseed oil because fresh-ground whole seeds also contain lignan, which might be as important as the omega-3s in producing any beneficial effects, she notes.)
The flaxseed study illustrates why it is important to keep investigating foods that are already thought to have health benefits. “There’s a lot of quackery in nutrition,” Demark-Wahnefried says. “Very few items have really been tested.” In the flaxseed study, which was performed in 161 men as they awaited surgery for prostate cancer, “we had presumed it would affect testosterone levels, which it didn’t do in this trial since men in the control group also had big decreases in hormone levels—probably due to increased stress,” she says. Follow-up studies showed “the flaxseed almost acts as a COX-2 inhibitor”—a class of drugs with anti-inflammatory effects—and it also affected a cancer pathway known as NF kappa B. “Sometimes you do these trials, and you suspect one specific mechanism is responsible, and then you realize other things may be happening.”
Finding New Hope
Demark-Wahnefried is now working on a breast cancer study called ENERGY (Exercise and Nutrition to Enhance Recovery and Good Health for You) with researchers in San Diego, St. Louis, and Denver. ENERGY, which will recruit 800 overweight or obese women who are up to five years post-diagnosis, is examining whether weight loss can impact long-term survival.
As she adjusts to her new life in Birmingham, Demark-Wahnefried plans to resume one of her own favorite exercise and stress-reducing activities—ballroom dancing with her husband. In a region known for going heavy on ham hock in vegetables and light on exercise, Demark-Wahnefried says she is hopeful that she can continue to uncover new ways to help people sidestep the ravages of cancer. “Being able to make a difference is important,” she says. “There’s so much that could be done here.”