Broccoli in skillet

Q&A: Cutting-edge research explores how diet causes and prevents cancer

August 14, 2015

Roderick Dashwood, PhD, has always zeroed in on why things don’t work. “During biology classes when we were learning things like how the heart works,” he said, “I was interested in why it stops working and what causes it to go awry. “It wasn’t a morbid curiosity, either. I wasn’t interested in death for the sake of death. Understanding abnormal aspects helps you understand normal biology better.”

His early interests led him to study genetic toxicology—how our environment, diet and lifestyle affect our DNA—at the undergraduate, masters and doctoral levels. Now director of the Center for Epigenetics and Disease Prevention at the Texas A&M Health Science Center Institute of Biosciences and Technology (IBT) in Houston, Dashwood still asks questions about abnormal biology, particularly cancer.

His research focuses on epigenetics and cancer prevention is representative of the caliber of work being conducted at the IBT. The English native participated in a Q&A to elaborate on his research and why it matters.

How did you come to direct the Center for Epigenetics and Disease Prevention?
About two years ago, IBT Director Dr. Cheryl Walker invited me to give a seminar at the Texas Medical Center. At the time, I was naïve about Houston, with visions of tumbleweeds and spittoons. But upon arriving, I was blown away by the huge concentration of medical expertise in one square mile and impressed that the science was so highly cooperative. After my seminar presentation, Dr. Walker mentioned plans for a new IBT center focused on epigenetics. That’s where it all started.

What is the field of epigenetics and how did it evolve? 
Epigenetics is the study of heritable changes in gene expression that are not caused by changes in DNA sequence. The medical profession historically has understood cancer development as changes in DNA sequence—either change in individual bases in the DNA or whole-scale changes that lead to chromosome rearrangement. But re­searchers started realizing that there were instances of tumors arising in humans and in animals that didn’t have genetic changes as the main driver of cancer development.

How can dietary choices and the beneficial components of food be utilized to prevent or fight cancer?
If a cancer has epigenetically-silenced genes, the hope is that through diet and lifestyle, we can open up chromatin, turn genes back on and trigger cancer cells to die. We study scenarios in which cancers in the human population are high or low and try to correlate those rates to dietary and lifestyle practices. Going deeper, we try to pinpoint particularly beneficial or harmful components of our foods. Our goal is to understand which foods might cause or prevent cancer and what we can do to optimize preventive strategies.

What foods have been identified that may help prevent cancer?
One group includes cruciferous vegetables like broccoli, cabbage, cauliflower and bok choy. Others include allium vegetables such as onions, garlic and shallots, which are high in beneficial sulfur compounds; foods like Brazil nuts that have high selenium content; and spinach, which has abundant chlorophyll. One way to optimize foods is to grow them in different types of soils and climate conditions.

What is chemoprevention?
Cancer chemoprevention refers to the use of natural, synthetic or biological chemical agents to reverse, suppress or prevent invasive cancer development. It has been studied extensively through various agents like vitamins, minerals and certain supplements or whole foods. It also includes the identification of so-called early biomarkers, which might be used as early predictors of cancer. Much of the historic medical focus on cancer has centered on therapy, which is certainly important. When people come into hospitals or clinics with cancer, we need immediate ways to help them—typically via surgery, radiotherapy or chemotherapy. However, this approach tends to categorize cancer as an event, when it is actually a process. What causes a cancer is usually a series of biochemical or molecular processes that accumulated over time—maybe the patient smoked cigarettes, stayed out in the sun too long, ate the wrong foods, or all of the above. We need to understand the carcinogenic process and how components in our food might act at steps along the way in order to potentially prevent tumors from ever happening. That has been my No. 1 driving passion throughout my career.

Were you a science geek as a child? 
While I loved science, I wasn’t a typical geek. My parents required me to choose one artistic pursuit and one physical pursuit outside of school, so I chose judo and classical guitar. I grew up hearing great Nobel laureates speak at Cambridge University, like Watson & Crick (discoverers of the DNA double helix structure) and Max Perutz (who was influential in identifying the structure of blood transport proteins like hemoglobin). I remember Perutz saying, ‘Students these days work too hard and think too little.’ He meant to remind us that while we’re in our labs, buried in the technicalities of our experiments, we have to keep perspective about what we’re doing and its potential impact.

Dashwood holds joint professorships in the Department of Nutrition and Food Science and the Texas A&M University College of Medicine. He is also a professor in the Department of Clinical Cancer Prevention at MD Anderson Cancer Center.

This article originally appeared in the Texas A&M Foundation’s Spirit Magazine.

— Holly Shive

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