Colon cancer sees alarming rise in young adults; Scientists blame this popular food habit

In recent years, doctors have witnessed a disturbing trend: colon cancer – traditionally viewed as a disease of older adults – is increasingly striking people under 50.

Scientists are pointing fingers at a common dietary culprit: it’s the ultra‑processed foods.

These time-convenient snacks, ready-to-eat meals, and sugary drinks are now linked not only to obesity and metabolic issues but also to more direct threats, like gut inflammation, harmful bacteria, and DNA‑damaging toxins. This unexpected connection invites us to rethink our food choices and recognize that what we snack on today could impact our health decades later – potentially changing how we prevent, detect, and treat colon cancer in tomorrow’s adults.


Fact-backed theory:

One leading theory links this increase to obesity, which is also on the rise in the US. A study from 2019 found that women with obesity were nearly twice as likely to develop early-onset colorectal cancer . Alarmingly, nearly half of all US adults are expected to be obese by 2030, according to the same research, published in the journal BJS by Oxford University Press.


Obesity can lead to inflammation and higher insulin levels, which increase the risk of various cancers, including gastrointestinal ones, as noted by the Centers for Disease Control and Prevention (CDC). Other risk factors include smoking, alcohol consumption, a Western-style diet, and non-alcoholic fatty liver disease.

Recent studies have also highlighted the role of a gut toxin called colibactin, produced by E. coli bacteria, which can damage DNA in colon cells and raise the risk of cancer. While the specific causes remain unclear, it's an issue not just in the US. “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 .

In the US, there has been a “marked increase” in early-onset gastrointestinal cancers among both men and women since the mid-1990s. Those born in 1990 are now 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 has become the leading cause of cancer-related deaths, while for women in the same age group, it’s the second leading cause.


What is colon cancer?

Colorectal cancer, also known as colon cancer, is a type of cancer that develops in the tissues of the colon or rectum. It's one of the most common types of cancer worldwide and the second leading cause of cancer death in the United States. Thanks to obesity and alcohol consumption, bowel cancer has become the primary cause of the rising death toll among young adults.


The colon and rectum are both parts of the large intestine, which is part of the digestive system. Colorectal cancer often begins as a growth called a polyp inside the colon or rectum. Most colorectal cancers are curable when localized to the bowel. However, recurrence following surgery is a major problem and is often the ultimate cause of death. Colorectal cancer can develop when cells in the colon or rectum change and no longer behave normally. These changes can lead to precancerous conditions, such as adenomas, or colorectal cancer itself. The most common type of colorectal cancer is adenocarcinoma, which starts in the gland cells that line the colon or rectum.

Colorectal cancer, the most common gastrointestinal cancer, disproportionately affects Black, Hispanic, Indigenous, and Asian populations.


Reasons behind colorectal cancer:

Colorectal cancer can be caused by several factors. Inherited genetic mutations or variants can increase the risk of colorectal cancer. Certain genetic conditions, such as Lynch syndrome and familial adenomatous polyposis (FAP), can also increase the risk. Besides, unhealthy lifestyle choices can increase the risk of colorectal cancer. A diet low in fruits and vegetables, high in fat, and low in fibre, and high in processed meats contributes to this kind of cancer. Being overweight or obese and a lack of regular physical activity are glaring reasons for colorectal cancer in millennials and Gen X. Habits like smoking and excessive alcohol consumption also catalyze this cancer. Alcohol consumption has been linked to early-onset bowel cancer, which tends to be more aggressive and lethal when compared to the kind that’s diagnosed in older individuals.

As per doctors, being overweight or obese – and related health conditions like hyperglycemia and diabetes – are the primary factors responsible.

In the late 1990s, colorectal cancer was the fourth-leading cause of cancer deaths in both men and women younger than age 50. Now, according to the American Cancer Society, it is the leading cause of cancer death among men and the second leading among women.



The practical resolution:

Given these worrying trends, researchers suggest that treatment practices may need to be updated. Young patients often face delays in diagnosis as both doctors and patients may not suspect cancer. As a result, many are diagnosed at later stages and tend to receive aggressive treatments, which may not always offer a survival advantage.

Colorectal cancer ranks as the third leading cause of cancer-related deaths among American men and fourth among women, and it’s expected to cause around 52,900 deaths this year, according to the American Cancer Society. These younger patients often face additional challenges, including financial strain, body image concerns, mental health issues, and a lower quality of life.

Dr. Char emphasized the importance of 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.”