In This Issue
CBS Prof Explores Diet, Cancer Links
Scientist studies breast, prostate cancer risk
BY ANDREW VOWLES
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Omega-3 fatty acids in foods such as eggs and salmon can inhibit cancer growth, says newly arrived CBS professor David Ma, whose research plate includes studies of the links between diet and the two most common forms of cancer in Canada. Photo by Martin Schwalbe |
The new weapon in the fight against cancer is your dinner plate, says Prof. David Ma, Human Health and Nutritional Sciences (HHNS). Newly arrived at Guelph this fall, he is studying how what you eat and drink may help protect you against the two most common forms of cancer in Canadians.
Breast cancer strikes more than 22,000 women each year and causes more than 5,000 deaths (second only to lung cancer), according to statistics from the Canadian Cancer Society. In men, the most common form of cancer is prostate cancer; about 22,300 men will be diagnosed this year and about 4,300 will die from it. Here at Guelph, Ma studies nutritional links to help prevent both diseases.
The American Institute for Cancer Research estimates that as many as 40 per cent of cancer cases are preventable through diet and physical activity. Add in growing attention being paid to the role of nutrition in preventing a variety of ailments, says Ma. “People are interested in nutrition and disease.”
If you can't do much about the genes you're born with, you do have some control over what you eat — or don't eat. Referring to the possibility of making a difference for people in their kitchen and in restaurants, he says: “It's adding that applied health component.”
Ma is digging into connections between breast cancer and omega-3 fatty acids and conjugated linoleic acids. He began that work as a graduate student at the University of Alberta and pursued it as a post-doctoral researcher at Texas A&M and as a faculty member for the past three years at the University of Toronto.
Fats such as omega-3 fatty acids have been shown to inhibit cancer growth. But like other mammals, humans can't make omega-3 and need to find it in their diet, from salmon to supplements. What happens when we eat varying amounts? Research by Ma and others suggests that early nutrition is critical to later development of cancer. By studying mice, he hopes to trace the life-cycle connections between food and disease.
He also plans to study prostate cancer risk and what men are eating — or not eating. His interest here is in trans fats, already pegged for their links to cardiovascular disease. Several studies suggest they are also implicated in increased cancer risk, especially prostate cancer.
Ma hopes to learn more about whether specific kinds of trans fats affect cancer risk. Not all trans fats are equal, he says. Artificially created forms found in baked goods appear to be more harmful than natural trans fats commonly found in dairy products and beef.
He hopes to learn about genetic determinants of prostate cancer as well — the kind of thing that separates one consumer from another.
“Maybe you can eat fried chicken all day and have high trans fats, but your overall risk is minimal if you have the right genes, or vice versa,” he says. “This is an example of how personalized medicine can be applied through nutrition.”
Ma is also interested in learning whether consumers' ethnic background affects prostate cancer risk.
He will draw on tissue samples housed in the lab of his collaborator Robert Nam, a clinical oncologist at Sunnybrook Health Sciences Centre in Toronto. Working with about 175 of those samples, they have already drawn links between higher levels of dietary trans fats and more aggressive forms of prostate cancer.
Next up: expanding the study to all 3,000 samples, representing a range of ethnic groups. There's evidence that risks vary for, say, Caucasians and African-Americans.
Pointing to Canada's multicultural makeup, Ma says: “We want to tackle a pertinent health question for Canadian men.” (There's also a personal angle: his father recently underwent prostate cancer treatment.)
His lab in the Animal Science and Nutrition Building can analyze samples and identify specific forms of trans fats to tease out these relationships.
Ma studied cancer as a faculty member in the nutrition department of U of T's Faculty of Medicine before joining Guelph this year. He says U of G offers opportunities to expand his research program and provides access to like-minded faculty and research facilities such as the Advanced Analysis Centre in the science complex.
Does he heed the lessons of his own research? “Have everything in moderation is probably the best advice,” says Ma, who keeps his own omega-3 levels up by consuming eggs, milk and salmon, and tries to limit junk food. “I enjoy my potato chips — and one can indulge once in a while.”
Recognizing the fitness and exercise side of the equation, he golfs and burns more than a few calories running after his 14-month-old son, Noah. His wife, Soo Min Toh, teaches human resources management at the University of Toronto. (They live in Mississauga, where Ma catches the new GO Transit bus service to Guelph from Square One.)
Ma had planned on a career in medicine and studied biochemistry as an undergraduate at the University of Alberta. But that changed after a summer research position in Alberta.
“I'm really a bench researcher,” he says, referring to the basic kinds of questions he's trying to solve. “That's what brings me to work every day — the opportunities to ask interesting research questions and having the ability to answer them.”