The wave of colon cancer among young people may be fueled by a surprising factor related to mental health

Stress and anxiety may partly explain why colon cancer rates are increasing among younger generations of Americans, a study suggests.

Researchers from China’s Sichuan University found that frequent stress causes some healthy bacteria living in the intestines to die, making it easier for cancer to invade.

When these bacteria die, tumors grow faster, leading to more aggressive, fast-growing colorectal cancers.

These findings come amid a rise in cases of bowel and rectal cancer in young people in the US and Britain – which experts have previously attributed to diet.

Data from JAMA Surgery shows that colon cancer is expected to increase by 90 percent in people ages 20 to 34 by 2030

However, an emerging field of science suggests that the gut and the body’s microbiome may play a role.

At the same time, data shows that more young Americans and Britons than ever are constantly stressed, anxious or depressed. Polls consistently show that younger generations are under more pressure than any other demographic group.

A 2023 study of the American Psychological Association found that the average 18 to 34 year olds rate their stress level at a six out of ten, while people aged 65 and over rate their stress just above a three.

The US has the sixth highest rate of early-onset cancer (87 cases per 100,000 people) and colorectal cancer (CRC) is among the fastest rising.

The number of diagnoses among people under 50, who are classified as early-onset, is expected to increase by 90 percent between 2010 and 2030 in people aged 20 to 34.

A number of factors are suspected of causing the emergence of the disease in young people: a diet of highly processed foods and energy drinks, obesity, a disruption of beneficial bacteria in the gut and, more recently, high blood sugar levels.

Overuse of antibiotics is also mentioned as a factor, but as a separate factor study in the journal Clinical Gastroenterology and Hepatology, found that the study examining this link reported conflicting findings and that newer results were not statistically significant.

When taken sparingly, antibiotics are very effective, safe treatments for bacterial diseases. These drugs have revolutionized the way doctors fight infections.

But if taken too often, they can cause a major disruption in the healthy bacterial colonies that live in the gut: the body’s microbiome.

The team from China therefore used an antibiotic cocktail to test their theory.

The research was presented at United European Gastroenterology Week 2024, but has yet to be published in a journal or peer-reviewed, meaning the full details of the study – conducted in mice – are not known.

Lead researcher Dr Qing Li said: ‘In our study, we used an antibiotic cocktail to eradicate the gut microbiota, followed by fecal microbiota transplantation to investigate whether the gut microbiota was necessary for chronic stress to accelerate the progression of CRC.’

Fecal microbiota transplantation is a scientific term that means researchers transfer healthy poop into the body of someone with an unhealthy gut, with the goal of repopulating their gastrointestinal tract with healthy bacteria.

They supplemented mice with colon cancer with a healthy poop sample, exposed the mice to stress and watched what happened to the progression of their cancer.

The Lactobacillus plantarum bacteria live naturally in the intestines and in some fermented foods. Researchers found that tumors grew more easily when they were absent from intestinal cells

In another group of mice with colon cancer, they introduced antibiotics to kill bacteria in the intestines and exposed the animals to stress.

In mice without gut bacteria, tumors grew faster than when they had a robust microbiome to protect them.

Furthermore, researchers showed that even if no antibiotics were introduced into the system, stress alone can dampen the microbiome, making the body more susceptible to tumors.

Stress alone could therefore make colorectal cancer and tumors more likely, the study authors suggest.

One group of bacteria in particular seemed to be particularly affected by antibiotics and stress: lactobacillus.

Older research Trinity College in Ireland has suggested that these bacteria support the body’s immune system, can protect against viruses and bacteria, and prevent damage to intestinal cells.

This bacteria occurs naturally in many fermented foods and in the human body. When the body was exposed to antibiotics, lactobacillus was completely depleted in both groups tested.

Dr. Li said: ‘This depletion highlights its critical role in maintaining gut health and its possible association with colorectal cancer progression under chronic stress.

‘Restoring beneficial bacteria in the gut, such as Lactobacillus, could boost the body’s natural defenses against colorectal cancer.’

Doctors could use Lactobacillus to treat colon cancer in the future, Dr. Li suggested.

The above shows the symptoms and their frequency in early-onset patients, who develop colon cancer before the age of 50, and in late-onset patients, who develop the cancer after this age.

There are an estimated 100 trillion bacteria living in and around the digestive tract – more than the number of cells in the body – according to research by Emory University.

They help keep the area lubricated, aid the body in breaking down food, and can even produce neurotransmitters and vitamins that the body needs to function.

Research from the University of Missouri-Kansas City found that colorectal cancer rates increased 500 percent among children ages 10 to 14 and 333 percent among teens ages 15 to 19.

Rates rose 71 percent among people aged 30 to 34 to seven cases per 100,000 people. And among people aged 35 to 39, the rates rose by 58 percent to 12 cases per 100,000 people.

The number of cases of colorectal cancer in people aged 10 to 44 has increased in all age groups.

The rate of colorectal cancer grew by 500 percent among children aged 10 to 14 and by 333 percent among teenagers aged 15 to 19.

Rates rose 71 percent among people aged 30 to 34 to seven cases per 100,000 people. And among people aged 35 to 39, the rates rose by 58 percent to 12 cases per 100,000 people.