Colorectal Cancer in Young Adults: Diet, Stress, and Emerging Risk Factors

A report in May expanded on a worrisome trend in adults under 45. Here’s what it found, as well as colorectal cancer symptoms and risk factors.

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Over the past 20 years, colorectal cancer has increasingly affected younger people in the United States. Research indicates a significant rise in the incidence rate of colorectal cancer among those under 45, with a fivefold increase among children aged 10 to 14. This notable trend has garnered widespread attention, prompting recommendations to further lower the current screening age of 45. Experts also urge the public to enhance their awareness of colorectal cancer and to manage modifiable risk factors, such as poor diet and unhealthy lifestyle habits.

According to 2023 statistics from the American Cancer Society, colorectal cancer is the second-deadliest cancer in the United States after lung cancer. More than 153,000 people in the United States were diagnosed with colorectal cancer, and 52,550 are expected to die from the disease. Among these, 19,550 cases and 3,750 deaths involve patients under the age of 50, classified as early-onset colorectal cancer.

Even more concerning is that younger people are often diagnosed at a later stage as they are below the screening age. By then, colorectal cancer is prone to metastasis and spread, making it much harder to treat.

Report Reveals ‘Very Concerning Trends’

A study presented at the Digestive Disease Week 2024 event in May utilized the U.S. Centers for Disease Control and Prevention’s (CDC) WONDER database to analyze the incidence rates of colorectal cancer from 1999 to 2020. The changes in colorectal cancer incidence rates for each age group are as follows:

• Ages 10 to 14: increased by 500 percent
• Ages 15 to 19: increased by 333 percent
• Ages 20 to 24: increased by 185 percent
• Ages 25 to 29: increased by 68 percent
• Ages 30 to 34: increased by 71 percent
• Ages 35 to 39: increased by 58 percent
• Ages 40 to 44: increased by 45 percent

“This data reveals some very concerning trends, particularly in our younger population who do not typically come to mind when considering CRC (colorectal cancer) screening for patients,” Dr. Islam Mohamed, the study’s lead author and an internal medicine resident at the University of Missouri–Kansas City, said in a statement.

Recognizing Colorectal Cancer Symptoms

Cancer is generally considered a disease that primarily affects older adults. For many years, the recommended screening age for colorectal cancer in the United States was 50. However, due to growing concerns about the increasing incidence of colorectal cancer among younger individuals, the American Cancer Society lowered the recommended screening age to 45.

This study primarily studied people under 45, as they are not included in the current screening guidelines. This oversight increases the risk of missing early detection and treatment opportunities for colorectal cancer, particularly among children and adolescents.

Mohamed said in the statement that regardless of age, the possibility of colorectal cancer should not be ruled out if related symptoms are present. “It’s important that the public is aware of signs and symptoms of colorectal cancer,” he added.

Patients with early-onset colorectal cancer may experience changes in bowel habits, abdominal pain, or rectal bleeding. Mohamed noted that if these symptoms occur, taking them seriously and seeking timely evaluation is essential.

According to the American Cancer Society, while there is no definitive method to prevent colorectal cancer, screening can detect abnormal cells before they progress to cancer. Additionally, managing modifiable risk factors may help reduce the risk of developing cancer.

Risk can be managed through multiple approaches, including dietary management, weight control, and physical activity. For example, consuming more vegetables, fruits, and whole grains while reducing intake of red and processed meats may help lower the risk of colorectal cancer. Additionally, avoiding smoking and reducing alcohol consumption can also contribute to a lower risk. In the United States, alcohol consumption is associated with approximately 6 percent of cancer cases and 4 percent of cancer deaths.

Primary Risk Factors for Colorectal Cancer

In April, Dr. John Marshall, associate director of clinical care at the Georgetown Lombardi Comprehensive Cancer Center and a gastrointestinal cancer expert, emphasized in an interview with Katie Couric the importance of a healthy gut microbiome in preventing colorectal cancer and maintaining overall health.

“[Modern lifestyles] somehow changed our own internal microbiome. ... We think it is a large part of our immune system,” he said.

The gut microbiome serves as a protective barrier against pathogens and infections in the gut and regulates inflammation by influencing the immune system. These functions play a crucial role in the development of colorectal cancer.

Marshall said that young people in modern environments are exposed to more colorectal cancer risk factors, including poor dietary habits (such as high consumption of processed foods), obesity, and frequent use of products containing microplastics.

The American Cancer Society identifies obesity, high consumption of red and processed meats, smoking, and alcohol use as modifiable risk factors for colorectal cancer. In contrast, genetic factors, which are nonmodifiable, account for only about 5 percent of colorectal cancer cases.

A 2022 systematic review of early-onset colorectal cancer supported the American Cancer Society’s dietary recommendations. The study found that individuals with poor nutritional habits—such as high consumption of fried and processed foods, high-fat diets, and sugary drinks and desserts, along with low intake of folate and fiber—had a significantly higher likelihood of developing colorectal cancer before age 50.

Additional Risk Factors

In addition to diet, many other factors influence the occurrence of colorectal cancer. Dr. Jingduan Yang, CEO of Northern Medical Center in New York, told The Epoch Times that decreased immune function, increased psychological stress, poor sleep, and insufficient physical activity all contribute to health problems and elevate the risk of cancer.

Another emerging risk factor that has garnered widespread attention is microplastics. Defined as plastic particles smaller than 5 millimeters in diameter, microplastics are pervasive in the air, water, food, and everyday products. When ingested, they can cause physiological changes in the gut. One study found that microplastics can reduce the thickness of the intestinal mucus layer and damage it, impairing its barrier function. This makes it easier for pathogens and toxins to penetrate the colonic mucosa, increasing the risk of developing colorectal cancer.

Yang noted that microplastics may release carcinogenic substances, increase inflammation, induce oxidative damage in the body, and even lead to DNA mutations. Therefore, minimizing the use of products containing microplastics and nanoplastics is advisable to reduce the risk factors for colorectal cancer and other diseases.