You Aren’t What You Eat—You’re What You Metabolize

Discovering new ways food can impact colorectal cancer risk

a plate on a table with a fork and knife - half of it contains spinach salad and the other half contains a hamburger and fries

When Harvard researcher Paulette Chandler, MD, MPH, was just 15 years old, her father received news from the doctor: he had lung cancer, and it was inoperable.  While trying to cope with the enormity of what that meant, Chandler came across an article in Life Magazine about a doctor with cancer who had changed his diet, and his disease went into remission. Chandler shared the story with her father, and with her help, he adopted a plant-based diet.

Although her father died several months after he was diagnosed, the notion that diet could impact health stayed with Chandler and had a profound effect on her life. Soon after, she decided she would pursue a path that would allow her to better understand how nutrition may affect cancer and hopefully one day help other families dealing with the disease.

Today she is doing just that, working as an assistant professor of medicine at Harvard Medical School and an associate epidemiologist in the Division of Preventive Medicine, Brigham and Women’s Hospital in Boston, Mass. Specifically, she’s conducting research in collaboration with the lab of Clary Clish, PhD, Director of the Metabolomics Program at the Broad Institute of MIT and Harvard, looking at the way certain diets increase or decrease the chance of developing colon cancer. In June 2015 she began this work, after receiving a 5-year grant of $726,000 from the American Cancer Society.

“Despite an abundance of research about the association between diet and risk of colorectal cancer, little research has been done to look at the biology behind what is happening—specifically, what happens when you consume a traditional Western diet [a lot of processed meat/lack of fruits and vegetables] and how might that contribute to cancer?” says Chandler.

Chandler is looking at how certain foods increase levels of dietary byproducts known as “metabolites.” Metabolites are small molecules in the bloodstream that can be measured and provide clues into how different foods impact colorectal cancer risk. The way different foods get broken down in the bloodstream by the body – and the amount and type of metabolites they produce – has a significant effect on your health.   

Chandler is using plasma samples from several studies to look at about 2,700 different metabolites, including those related to diet and gut bacteria. She’s comparing the typical Western diet to the healthier Mediterranean diet to see how they might contribute to the risk of colorectal cancer.

A typical Western diet of high amounts of processed food and less consumption of fruits and vegetables can lead to inflammation in the gut. The Mediterranean diet seems to do the opposite – with high intake of leafy greens, fruit, and fish keeping the gut healthy. Researchers have known for a long time that chronic inflammation in the gut is linked to colorectal cancer. However, they still don’t know exactly why that is. That is part of what Chandler wants to find out.   

Bottom line

If her theories prove correct, she’ll be able to show that the way the body breaks down foods associated with a Western diet increases risk of colorectal cancer while how the body breaks down Mediterranean diet foods decreases colorectal cancer risk.

“The bottom line is, we are not what we eat but what we metabolize,” says Chandler. “The blood tells a story about what you eat and what will develop as a result of what you choose to eat.” 

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