Bounty of the Mediterranean
U-M researcher examines diet's potential for preventing cancer
Researchers have long noted that populations living along the Mediterranean Sea have lower risk of cancer, heart disease and stroke. The lower risk may be linked to the regional diet -- one high in vegetables, whole grains, fruits, fish and olive oil. To better understand the potential benefits of a Mediterranean diet, Zora Djuric, Ph.D., a research professor of family medicine at the University of Michigan Medical School, has developed a study to examine the role of diet in preventing colon cancer. We talked with her to learn more about her research.
Q: What is it about the Mediterranean diet that makes it a good candidate for preventing colon cancer?
A: The various components of the diet seem to be a preventative for cancer. For example, increased fish intake and increased intake of certain vegetables may have a beneficial effect. It's also the large variety of fruits and vegetables that are consumed in a Mediterranean diet. Different types of fruits and vegetables have different nutritional compounds, or phytochemicals, in them.
Q:It seems we read regularly about new research related to phytochemicals, such as omega-3 fatty acids or beta carotene, in food. Which ones are important?
A: The Healthy People 2010 diet calls for eating plenty of fruits and vegetables and whole grains. It moderates fat intake and limits saturated fat. The Mediterranean diet favors monounsaturated fats from olive oil, nuts and fatty plant-based foods, such as olives. It also requires whole grains; low-fat protein, such as poultry, fish and legumes; and seven to nine servings from two fruit categories and six vegetable categories to ensure variety.
Q: How well have study participants been able to follow the diets?
A: We were pleased that people were able to do it. It sounds complicated - and it does take time to figure out how to eat everything -- but that's why we offer dietary counseling to ensure that the eating plans are working. People seem to like the Mediterranean diet, maybe because of the higher fat intake. It's very palatable, and that's really important. You can dream up the best diet, but if no one wants to eat it, it's not going to prevent cancer.
Q: Do you have other Mediterranean diet studies planned?
A: Yes, we're writing a grant now to study the diet's effect in breast cancer survivors. People with other types of cancer tend to lose weight, but not those with breast cancer -- and we don't know why. An important goal of that study will be to look at preventing body fat gain. An earlier pilot study we conducted among women in 2007 seemed to indicate that this diet may be helpful. The women who ate a Mediterranean diet decreased the amount of polyunsaturated fat they ate by 50% while increasing monounsaturated fats by the same amount. They also ate twice as many fruits and vegetables, doubling their blood levels of carotenoids.
Q: So the Mediterranean diet could be beneficial for survivorship as well as prevention?
A: Absolutely. Unfortunately, research has shown that survivors tend to have more health problems than those who haven't had cancer. The Mediterranean diet seems to lower the risk for several diseases, including cardiovascular disease and diabetes. It can be difficult to change the way you eat, since a lot more is wrapped up in food than health: It's about customs and values and feeding ourselves emotionally. But hopefully people will find it worthwhile, particularly if it tastes good.
Read the Spring, 2011 issue of Thrive.