The Complexity of Cancer and Food

June 05, 2014

Cancer is scary. It is a complex disease that does not discriminate — it can impact all parts of the body, and all ages, young and old, without warning.

Most people have an experience with cancer either personally or through family, friends, coworkers or others they know. My experiences involve many people like my cousin, Scott, who was close to my sister’s age and lived a block away from us growing up—he was almost in the 2nd grade when he passed away. Scott maintained his childhood sweetness and wonderment at the little things through his short life; there was nothing his parents, support network and medical staff did not try to help him beat cancer. More recently my friend Dena lost her life to cancer right before her 30th birthday. I also am a registered dietitian (RD) and worked at Beth Israel Deaconess Medical Center in Boston for about 5 years, where I met and worked with many patients, some of them with cancer.

As an RD, I wish we knew more about how to reduce the incidence of this horrible disease, but the reality is cancer, the second most common cause of death in the U.S., is a multifaceted disease that appears to result from the interaction of multiple genetic and environmental factors. Among the environmental factors, diet and nutrition, including milk and milk products, have received considerable attention as potential modifiers of cancer risk, but we still have a long road of discovery ahead.

Researchers think diet is an important modifiable environmental factor that can modify disease risk.  But because foods contain nutrients and other components that may either increase or decrease cancer risk, and because each cancer is different – it is extremely difficult to establish dietary recommendations.

Nutrition science is continually evolving and new mechanisms connecting diet and disease risk are being discovered routinely.  Conflicting reports as well as misinformation about food and disease can create public confusion, even when it comes to foods that are considered nutrient-rich. That’s why it’s important to look at the big picture and consider the entire body of scientific research on any topic — in this case, the role of dairy foods and cancer.

An extensive body of research has examined the potential of milk and milk products and their nutrients (e.g., calcium and vitamin D) and the impact on specific cancers, such as colorectal cancer, breast cancer, and prostate cancer. According to a comprehensive review by Davoodi et al., “the evidence indicating healthful effects of milk and milk product consumption on prevention of cancer is considerably greater than those representing harmful impacts.”  Additionally, it is important to note, the American Cancer Society’s current nutrition and physical activity guidelines encourage consumption of low-fat and fat-free dairy foods.

In an effort to keep the scientific evidence related to diet and cancer current, the World Cancer Research Foundation/American Institute for Cancer Research (WCRF/AICR), in collaboration with the Imperial College London, has undertaken the Continuous Update Project (CUP). The CUP reports are a good resource when looking for a comprehensive review of the science on diet and cancer.

For most people, food has emotional connections including family traditions, philosophical and religious beliefs.  As a health professional your challenge is to help the public navigate the tricky world of diet and health based on comprehensive nutrition guidelines that are developed on the totality of existing science such as the Dietary Guidelines for Americans (DGA).

The DGA recommends Americans 9 and older consume 3 daily servings of low-fat or fat-free milk and milk products every day as part of a healthful, balanced diet. These recommendations highlight the key nutrient contributions and health benefits associated with dairy food consumption. Research published since the release of the 2010 DGA is consistent with and builds on the moderate evidence that dairy foods are associated with improved bone health, especially in children and adolescents, and moderate evidence that intake of milk and milk products is associated with a reduced risk of Type 2 diabetes and cardiovascular disease and with lower blood pressure in adults.

While there is evidence for the protective effects of milk and milk products and its components on certain types of cancer, there is a need for more research – particularly to identify the potential mechanisms involved.  So for all the other Scotts and Denas out there, nutrition science is continuing to progress – which will ultimately help health providers make the best possible recommendations for managing cancer risk.