Researcher progress report: The impact of diet on breast and colorectal cancers
Susan Steck, Ph.D., M.P.H., at the University of South Carolina was awarded the Prevent Cancer Foundation – Living in Pink grant last year for her project, “Dietary Inflammatory Index and Risk of Breast and Colorectal Cancers.” Now that she’s a little over a year into her two-year study, we asked for an update on her project.
1. What led to your interest in cancer prevention research in breast and colorectal cancers? Tell us a little about the connection between breast and colorectal cancer.
Breast and colorectal cancer are two of the most common cancers in the United States. Evidence shows that what you eat or drink may play a role in either promoting or preventing them. Your risk may be increased, for example, by excessive alcohol intake, eating charred or smoked meat—and not eating lots of fruits and vegetables. Identifying behavior that can be changed is an important step in designing effective interventions to prevent cancer. That is the aim of our research.
2. How is your research progressing?
Our study is assessing the inflammatory potential of diet in a large study of postmenopausal women, the Women’s Health Initiative. We know that there are many dietary factors that are pro-inflammatory, including saturated fat, trans fatty acids, high sugar diets and highly processed, energy-dense foods. There are even more dietary factors that are anti-inflammatory, such as phytochemicals and micronutrients found in vegetables and fruits, fiber and spices like ginger and turmeric. We developed a dietary inflammatory index as a way of scoring a person’s diet based on its inflammatory potential, all the way from pro-inflammatory to anti-inflammatory, and we are using this in the current study to examine if pro-inflammatory diets increase the risk of breast and colorectal cancers.
So far, our results suggest that a pro-inflammatory diet is associated with increased risk for colorectal cancer. However, our preliminary results do not show a similar link between a pro-inflammatory diet and increased risk for breast cancer. We are expanding the analyses to include risk of dying of breast cancer (in addition to risk of being diagnosed with the disease).
3. As you look forward to the second year of funding, what are your thoughts about this project?
This will be an extremely important study, because it is the first study to examine the relationship between this novel dietary inflammatory index and breast and colorectal cancer risk, and there are a large number of women in the study. Other researchers are already showing a lot of interest in the dietary inflammatory index, and they are starting to use it in other studies as well. Bottom line: this research project has really jump-started this new line of investigation and has led to many new opportunities for collaboration.
4. How will your current research project advance the field of cancer prevention?
Inflammation is a normal biologic process that occurs in response to acute injury and subsides once the healing process is complete. However, the presence of chronic, low-grade inflammation that can be caused by obesity, a poor diet, lack of physical fitness or environmental exposures can have a negative impact on health and can increase cancer risk. Our study results support the recommendations to move toward a more plant-based diet—to increase fruits and vegetables, legumes, whole grains and reduce fried foods and energy-dense processed foods—and then identify inflammation as a specific biologic process which may explain why a more plant-based diet is so beneficial.