Colon Cancer Soars in Young Adults: Diet to Blame?

Alarming new data reveals a disturbing trend: colorectal cancer, once considered an older adult’s disease, is increasingly affecting those under 50. Scientists are investigating dietary links, pointing to a prime suspect: ultra-processed foods.

The Western Diet Under Scrutiny

Characterized by high consumption of processed foods, refined carbohydrates, added sugars, and saturated fats, the typical American diet is under scrutiny. This dietary pattern is low in fruits, vegetables, and whole grains, and has been linked to obesity, heart disease, and type 2 diabetes.

Time-saving snacks, ready-to-eat meals, and sugary beverages are now linked to risks beyond obesity and metabolic issues. These include gut inflammation, harmful bacteria, and DNA-damaging toxins. This connection urges us to reconsider our food choices.

Obesity’s Role in Early-Onset Cancer

Obesity, also on the rise, is a leading theory. A 2019 study revealed women with obesity were almost twice as likely to develop early-onset colorectal cancer. Almost half of U.S. adults are projected to be obese by 2030, according to research published in the journal BJS by Oxford University Press.

According to the Centers for Disease Control and Prevention (CDC), obesity may trigger inflammation and elevate insulin levels, heightening the risk of gastrointestinal cancers. Other risk factors include smoking, alcohol, a Western-style diet, and non-alcoholic fatty liver disease.

Recent studies also highlight the role of colibactin, a gut toxin produced by E. coli, which can damage DNA in colon cells. According to a 2024 American Cancer Society report, certain food contaminants can increase cancer risk.

While causes are still being investigated, this is not solely a U.S. problem. “The incidence of GI cancers in adults younger than age 50 is rising globally,” explained **Dr. Sara Char**, an oncology fellow at Boston’s Dana-Farber Cancer Institute.

A Generation at Risk

Since the mid-1990s, the U.S. has seen a “marked increase” in early-onset gastrointestinal cancers among both men and women. Those born in 1990 are twice as likely to develop colon cancer and four times more likely to develop rectal cancer compared to those born in 1950.

For men under 50, early-onset colorectal cancer is now the leading cause of cancer-related deaths, and for women in the same age group, it’s the second leading cause.

Understanding Colorectal Cancer

Colorectal cancer develops in the tissues of the colon or rectum, both parts of the large intestine. It often begins as a polyp inside the colon or rectum. Most colorectal cancers are curable when localized, but recurrence after surgery is a major concern.

Colorectal cancer develops when cells in the colon or rectum change and no longer behave normally, leading to precancerous conditions or cancer itself. Adenocarcinoma, originating in the gland cells lining the colon or rectum, is the most common type.

This cancer disproportionately affects Black, Hispanic, Indigenous, and Asian populations.

Risk Factors and Lifestyle Choices

Inherited genetic mutations, such as Lynch syndrome and familial adenomatous polyposis (FAP), can elevate risk. Unhealthy lifestyle choices such as a low-fiber, high-fat diet, particularly one rich in processed meats, also contribute.

Being overweight or obese coupled with inactivity are key factors in younger adults. Smoking and excessive alcohol consumption are also catalysts. Alcohol has been linked to early-onset bowel cancer, which tends to be more aggressive.

Doctors note that being overweight or obese, and related conditions like hyperglycemia and diabetes, are primary factors. In the late 1990s, colorectal cancer was the fourth-leading cause of cancer deaths in those under 50. The American Cancer Society now ranks it as the leading cause among men and second among women.

Improving Treatment and Outcomes

Researchers suggest treatment practices require updates, as young patients often experience delayed diagnoses. As a result, many are diagnosed at later stages and receive aggressive treatments that do not guarantee survival.

Colorectal cancer is the third leading cause of cancer-related deaths among American men and fourth among women; the American Cancer Society estimates it will cause around 52,900 deaths this year. Younger patients often face financial strain, body image concerns, mental health issues, and a lower quality of life.

**Dr. Char** stressed the need for continued research, stating, “Ongoing research efforts investigating the biology of early-onset GI cancers are critical to developing more effective screening, prevention, and treatment strategies.”