JAMA Oncology study links ultra-processed foods to colorectal cancer tumors in young women

Ultra-processed foods may be driving a global surge in colorectal cancer cases among women under 50, according to a first-of-its-kind study published Thursday.

Writing in JAMA Oncology, researchers led by Mass General Brigham in Boston analyzed survey responses of 29,105 female registered nurses in their 20s, 30s and 40s who participated in a national study from 1991 to 2015.

During those 24 years, 1,189 of them developed potentially cancerous tumors in their colons or rectums. For every 10 women with low ultra-processed food consumption who developed tumors, roughly 15 with high consumption developed them.

“The women who ate the highest level of ultraprocessed foods in our study had a 1.5-fold higher risk of developing a colon adenoma polyp before the age of 50, compared with those who ate the lowest level,” Dr. Andrew Chan, a gastroenterologist at Mass General Brigham who co-wrote the paper, said in an email.

Dr. Chan’s team used the 2009 Nova definition of ultra-processed foods as “industrially produced ready-to-eat or ready-to-heat products that contain minimal whole foods.”

“Ultraprocessed foods are typically low in bioactive compounds, such as dietary fiber, vitamins, and polyphenols, and high in unhealthy fats, refined starches, and food additives such as emulsifiers and artificial sweeteners, which could disrupt gut microbiota, increase intestinal inflammation, and contribute to colorectal carcinogenesis,” the researchers wrote.

The study noted that ultra-processed foods “high in red and processed meat and added sugars” have grown to comprise nearly 60% of Americans’ daily caloric intake since they hit supermarket shelves in the 1980s.

The findings come as Health and Human Services Secretary Robert F. Kennedy Jr. has made ultra-processed dyes and ingredients a key target of his Make America Healthy Again program, labeling them a major cause of chronic diseases like obesity and diabetes.

Meanwhile, women have led a surge in cancer diagnoses among young people. In January, the American Cancer Society reported that cancer rates “in women under 50 are now 82% higher than their male counterparts, up from 51% in 2002.”

Colon cancer develops in the large intestine, a key part of the body’s digestive system, and can be fatal if not treated early with surgery or medical therapies. Symptoms include constipation, diarrhea, cramps, fatigue, anemia and bloody stool.

The study published Thursday acknowledged that earlier research flagged an increase in sedentary habits and ultra-processed food consumption among young people as possible risk factors for colon cancer. But the researchers said more studies are needed to conclude that ultra-processed food is a cause of the affliction.

Several medical experts not connected to the study said its findings confirm the need for young adults to avoid diets high in red meat and meats processed with high sugar levels.

“Reducing these foods in our diets could play a vital role in protecting young adults from the growing threat of colorectal cancer,” said Dr. Craig Escude, a family physician and fellow of the American Academy of Developmental Medicine.

Dr. Ibraheem Karaye, director of the health science program at Hofstra University, said the study provides the Department of Health and Human Services with “direct evidence” to educate the public on how to avoid ultra-processed foods.

“These foods are designed to be convenient, highly palatable, and shelf-stable,” Dr. Karaye said. “Common examples include soft drinks, packaged snacks, sweetened breakfast cereals, processed sausages and hot dogs, and ready-to-eat frozen meals.”

In an emailed statement, the White House said the study proves the wisdom of the Trump administration’s health policies.

“As the old adage goes, ‘you are what you eat,’” said Kush Desai, a White House spokesman. “President Trump’s movement to Make America Healthy Again isn’t just informing government policymaking to reexamine our food supply, but bringing together parents, researchers, farmers, physicians, and businesses to better tackle America’s epidemic of chronic disease.”

Dietitians have long urged Americans to make home-cooked meals; opt for whole fruits, grains and vegetables; and avoid processed meals that contain added sugars and addictive chemicals.