If Cigarettes Were the Culprit in the 20th Century... Now, This Inflammatory 'Food' Is Driving Cancer Among Young People

Surge in Colorectal Cancer Among People in Their 20s and 30s
"Disrupted Gut Environment and Inflammation Linked to Colorectal Cancer"

'Ultra-processed foods' are being identified as a major cause of colorectal cancer among people in their 20s to 40s. These foods are believed to worsen the gut environment and trigger inflammation, thereby increasing the risk of cancer.

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Debbie Sridhar, Professor and Chair of Global Public Health at the University of Edinburgh, recently wrote in a column for The Guardian that "the incidence of certain cancers, including colorectal cancer, shows different patterns across generations."

In the past, cancer was predominantly seen as a disease diagnosed in people in their 60s and 70s and older, but in recent years, early-onset cases among those under 50 have been rising worldwide. In particular, the number of colorectal cancer cases surged from about 94,000 in 1990 to around 225,000 in 2019. According to a European study, between 2004 and 2016, the incidence of colorectal cancer among people in their 20s increased by 7.9% annually, by 4.9% in their 30s, and by 1.6% in their 40s.

However, people under 50 are often excluded from colorectal cancer screening programs, making early detection difficult. Professor Sridhar noted, "Most young patients are diagnosed late, after symptoms appear and the cancer has already progressed."

Professor Sridhar explained that 75% of all colorectal cancer patients had no family history or genetic factors, indicating that environmental factors have contributed to the rising incidence of colorectal cancer among younger people.

Rapidly rising colorectal cancer among younger generations... Are ultra-processed foods to blame?

Ultra-processed foods refer to products that are heavily processed industrially and contain additives rarely used in home cooking. Typical examples include snacks, instant noodles, carbonated drinks, frozen foods, and sausages. These foods are generally high in calories, sugar, sodium, and saturated fat, but low in dietary fiber, and are known to be causes of obesity, cancer, cardiovascular disease, type 2 diabetes, and depression.

They are also known to disrupt insulin signaling, cause chronic low-grade inflammation, and create imbalances in gut microbiota, all of which are strongly linked to cancer development. Consuming large amounts of ultra-processed foods reduces the diversity and number of beneficial gut microbes while increasing harmful bacteria. The resulting gut inflammation can spread throughout the body, raising the risk of chronic diseases such as colorectal cancer.

A large-scale cohort study conducted in the United States by researchers at Tufts University in Boston, Massachusetts, and published in the British Medical Journal in 2022, found that the group consuming the most ultra-processed foods had a 29% higher risk of developing colorectal cancer compared to those who consumed the least. The researchers noted that this figure remained significant even after accounting for body weight and nutritional status, indicating that ultra-processed foods can increase cancer risk regardless of obesity.

Professor Sridhar emphasized, "If smoking was the main culprit of cancer in the 20th century, ultra-processed food consumption may be its counterpart in the 21st century." She added, "Although the scientific verdict is not yet final, related research is accumulating rapidly." She continued, "It is often said that 'food is medicine.' Recent studies go a step further, showing that food can be a means of disease prevention."