commentFacebookPinterestLinkby Jen Shiori AdamsBuzzFeedBuzzFeed StaffI've been writing for BuzzFeed since 2021, focusing on food, beauty, fashion, and wellness, with my previous work appearing in StyleCaster, Real Simple, Business Insider, and more. Sasirin Pamai / Getty Images While there's no single proven cause in the uptick in cases among young people, it may be due to a combination of factors. { "id": 140596806, "buzz_id": 8063319, "index": 1 } Ponywang / Getty Images Younger people are consuming more ultra-processed foods, more sugar, and less fiber, Pashtoon Kasi, M.D., M.S., medical director of GI medical oncology at City of Hope Orange County, told BuzzFeed. They're also experiencing higher rates of obesity and metabolic dysfunction, alongside lifestyle factors like alcohol use and prolonged sedentary time. "We’re also learning more about how diet and exposures like antibiotics earlier in life may shift the gut microbiome ('the good bugs and the bad bugs') in ways that affect inflammation and cancer risk," he said. "Environmental exposures, including things like microplastics and other modern chemicals, are being studied as well, but the science there is still evolving." "The most important things someone can do are to be physically active, maintain a healthy weight, limit alcohol, and eat a fiber-rich diet centered on whole foods such as vegetables, fruits, whole grains, and legumes instead of packaged, ultra-processed foods," Dr. Kasi said. According to the World Cancer Research Fund, it's best to keep your red meat intake to 3 portions (350–500g) per week and avoid processed meats like bacon, beef jerky, and charcuterie cuts, as a diet with an excess of red meat can lead to an increased risk of cancer. While making healthy lifestyle changes is important, Dr. Kasi noted that many younger patients do "everything right" and still develop colorectal cancer, which is why it's just as crucial to take symptoms seriously. Rectal bleeding or blood in the stool is one of the most overlooked and misattributed symptoms. "Bleeding is often written off as hemorrhoids, stress, or something you ate," Dr. Kasi explained. "Beyond that, I worry when people ignore persistent changes in bowel habits (new diarrhea or constipation that doesn’t resolve, narrower stools, or the feeling you can’t fully empty), ongoing abdominal pain or cramping, and unexplained iron-deficiency anemia that shows up on labs (often felt as fatigue, weakness, or getting winded more easily). Unintentional weight loss is another red flag." Basically, the key is persistence: "If symptoms are new for you and don’t improve, they deserve a real workup, regardless of age." Because younger adults are less likely to be screened, their symptoms are often dismissed or misattributed, which can then lead to later diagnosis. Dr. Kasi recommends planning ahead. "For most people at average risk who feel well, the current US guidance is to start routine colorectal cancer screening at age 45," he said. "But as a medical oncologist, I think your 30s are a great time to get proactive about risk assessment: know whether your family members have had colorectal cancer, and tell your doctor if you have an inflammatory bowel disease like Crohn’s or ulcerative colitis, a known hereditary syndrome like Lynch syndrome, or a history of abdominal or pelvic radiation. Those factors can move screening earlier and/or make colonoscopy the preferred test." However, those with a strong family history of the disease should be screened sooner. "Start screenings around age 40 or 10 years before the youngest diagnosis in a first-degree relative, whichever comes first," he said. Individuals belonging to certain ethnicities should also be screened earlier, as instances of colorectal cancer are highest in Indian American and Alaska Native individuals, according to the American Cancer Society. Dr. Kasi also pointed out that newer non-invasive stool-based or blood-based screening tests are available. "They are not meant to replace the colonoscopy procedure but can serve as an adjunct tool and another non-invasive lens with these novel tests often referred to as 'liquid biopsies' for screening and early detection."