We Asked a Doctor What Young People Need to Know About Colorectal Cancer

Colorectal cancer is one of the leading causes of cancer death in those under 50. Many younger people are diagnosed in the later stages, because screening doesn’t usually start until age 45. However, screening—or lack thereof—is only one factor that contributes to risk.

We asked our chief medical officer, Sohaib Imtiaz, MD, why this is happening and what young people should know about colorectal cancer.

Q: Why are colorectal cancer rates rising in younger adults?

Imtiaz: We know that colorectal cancer rates are rising in young people, but the harder question is: why? We don’t have a conclusive answer, but, as you might guess, many of the theories come down to diet.

Ultra-processed food is everywhere. It’s becoming an increasing part of our diets. We’re also having more red and processed meat, which we know are associated with colorectal cancer.

Because of all this ultra-processed food in our diets, our gut flora is different from what it used to be. As it gets disrupted, we start to see increased rates of digestive problems generally.

Certain gut bacteria contribute to cancer by inducing DNA damage and promoting chronic inflammation that disrupts your intestinal barrier.

The gut microbiome also helps produce short-chain fatty acids that protect the colon. But if the microbiome is disrupted, you’ll have less of that protection.

Downstream, these effects can increase colorectal cancer risk.

Gut microbiome disruption is one theory, but we don’t have a definitive answer as to why rates are increasing among young adults.

Q: Can you do anything to prevent it or lower your risk?

Much of your risk for colorectal cancer comes down to sedentary lifestyle, microbiome changes, obesity, and ultra-processed foods.

While it’s not always preventable, you can lower your risk of colorectal cancer by adjusting certain lifestyle factors.

Maintaining a healthy weight, getting regular physical activity of 150-300 minutes a week, limiting your intake of red and processed meat to less than twice a week, increasing your fiber intake to 30-38 grams for men and 21-25 grams for women daily, avoiding smoking, and limiting alcohol intake can significantly reduce your risk.

There’s some evidence that adequate vitamin D intake can help reduce your risk.

Q: When should you start colorectal cancer screening?

Most healthcare systems start screening for colorectal cancer every 10 years at age 45 in adults with average risk. If you have a first-degree relative with a family history of colorectal cancer, then you should get a colonoscopy every 5 years, starting at age 40.

Colonoscopies are pretty invasive, and many people shy away from them because of what they involve. But you also have blood and stool-based tests that can screen for colorectal cancer, which you can start as early as your 40s. These tests screen for abnormalities, and if the results are concerning, your next step is a colonoscopy.