Ultra-processed foods may raise colon cancer risk in younger women, study finds

A new study from Mass General Brigham researchers has found that women under 50 who eat high amounts of ultra-processed foods face a significantly greater risk of developing precancerous colon growths, shedding light on a possible dietary factor behind the alarming rise in early-onset colorectal cancer.

The rise in early-onset colorectal cancer (EOCRC) has occurred alongside a growing consumption of ultra-processed foods — ready-to-eat products that are often high in sugar, salt, fat, and additives.

Researchers had previously found a link between these foods and colorectal cancer in general, but this is the first study to connect them specifically to early-onset cases.

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Methodology:

The study used data from the Nurses’ Health Study II, which has tracked the health of women born between 1947 and 1964 for several decades. Researchers looked at information from more than 29,000 participants who had undergone at least two colon screenings before age 50 and completed detailed diet surveys every four years. 

Based on these surveys, they estimated that the women ate an average of 5.7 servings of ultra-processed foods per day, making up about 35% of their daily calories—slightly less than the U.S. average.

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Dig deeper:

The researchers found that 2,787 women developed precancerous colon polyps. 

Those who ate the most ultra-processed foods—about 10 servings a day—had a 45% higher risk of developing adenomas, a type of polyp linked to early-onset colorectal cancer, compared to women who ate the least (around 3 servings a day). 

However, eating ultra-processed foods was not linked to another, slower-growing type of polyp called serrated lesions.

Big picture view:

Colorectal cancer was once considered a disease of older adults, but cases are rising among people under 50, especially in wealthier countries like the United States. Scientists aren’t sure why this is happening, but new research from Mass General Brigham points to diet as a possible factor.

In a study published in JAMA Oncology, researchers analyzed data from nearly 30,000 women and found that those who ate the most ultra-processed foods had a 45% higher risk of developing precancerous colon growths compared to those who ate the least. These growths, called adenomas, can sometimes lead to early-onset colorectal cancer.

The findings, part of the Cancer Grand Challenges PROSPECT team’s work, highlight a potential link between heavily processed foods and colon health—one that researchers say deserves closer attention.

What they're saying:

"Our findings support the importance of reducing the intake of ultra-processed foods as a strategy to mitigate the rising burden of early-onset colorectal cancer," senior author Andrew Chan, MD, MPH, chief of the Clinical and Translational Epidemiology Unit and a gastroenterologist in the Mass General Brigham Cancer Institute, said in a news release. "The increased risk seems to be fairly linear, meaning that the more ultra-processed foods you eat, the more potential that it could lead to colon polyps."

What's next:

The researchers emphasized that ultra-processed foods alone cannot explain the rise in early-onset colorectal cancer. 

They are continuing to investigate other possible causes and are also refining how these foods are classified, as some types may be more harmful than others.