I get nervous seeing the headlines about the rise in colorectal cancer cases. What can I do right now to lower my risk?
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We used to think of smoking and genetics as the big factors at play when we talked about cancer. Those traditional risk factors are still important, but they are not what’s driving the conversation today.
I’m a gastroenterologist, and every week I diagnose colon cancer or small pre-cancerous growths, called polyps. We’ve been seeing an alarming rise in these cases for several decades among younger people.
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One of the most common questions I get is: Why?
In general, people are smoking less than their parents and grandparents, and our genetics haven’t changed profoundly in the past few generations. That leaves us to grapple with the idea that part of the problem may lie in our lifestyle and environment. To be clear: Cancer can happen to anyone, and the cause is often unknown. It’s the result of numerous factors, many of which we have no control over, occurred early in life or we do not yet fully understand.
While we don’t have all the answers, each year new important clues emerge that are reshaping our understanding of the factors that might raise your risk.
Most of my patients know that ultra-processed foods may promote weight gain, or that screen time is linked to depression and poor sleep.
But cancer? That often surprises people. All five of the habits listed below are associated with an increased risk of colorectal cancer among younger people in their 20s, 30s and 40s.
These are also habits that are so pervasive in daily life that it’s easy to lose sight of how they may impact you down the line, especially if you do them every day for years on end. My intention when I tell people about these risk factors is not utter perfection. Instead, what I want is for you to fully understand the risks as I do – and then decide what makes sense for your goals.
For many people, cutting back on some of these habits – even a little – and replacing them with healthier ones may be worth the cost.
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1. Ultra-processed foods
Eating packaged snacks, microwavable meals and many shelf-stable foods considered ultra-processed aren’t just a problem for Type 2 diabetes or heart health. Large studies have found that diets high in ultra-processed foods are linked to getting colon cancer at a younger age. On the flip side, the nutrient in our diet that protects against colorectal cancer that’s notoriously low in ultra-processed foods? Fiber. For every 10 grams of fiber you eat per day – about the amount in a cup of beans – there’s a 10 percent lower risk of colorectal cancer.
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2. Sugary drinks
In one study, women who drank two or more sugary drinks a day in adolescence and adulthood had double the risk of being diagnosed with colorectal cancer before age 50 compared to those who drank less than one a week. Try swapping out your sugary beverage a few days a week with an herbal tea or infused water.
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3. Red and processed meats
While processed meats like hot dogs or cured bacon are linked to a higher risk of colorectal cancer, multiple large studies have found the association is still there for meats like steaks or hamburgers. Based on the data, I recommend limiting red meat to no more than three servings a week because that’s the range that most studies indicate is less likely associated with cancer. But, hang on – I’ve got good news too. Marinating your meat first and slow-cooking at lower temperatures might help lower red meat’s carcinogens.
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4. Screen time
This was an actual study: People who spent 1-2 or two hours a day sitting and watching TV-screens had a 12 percent increased risk of getting colon cancer at a younger age – even after accounting for diet, obesity and other physical activities. The American Cancer Society recommends 150-300 minutes of moderate intensity activity per week – and more steps per day seem to help, but any level of physical activity is welcome. A great study published in JAMA Oncology in 2023 found that people who moved fast for 3 minutes a day – think hustling to rush up the stairs or catch a bus – were about 30 percent less likely to die of several types of cancer than those without vigorous activity.
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5. Alcohol
Even as little as one drink a week is associated with an increased risk of colon cancer at a young age. Decades ago, studies that many experts now consider flawed suggested that a glass or two of wine a day was good for heart health. The problem is that alcohol is a carcinogen – it breaks down into a compound called acetaldehyde which can damage DNA. Decades of data show that wine does not help people live longer – meanwhile, people who drink more alcohol are more likely to die from cancer, including colon and breast cancers. Remember, as with all these risk factors, it doesn’t have to be all or nothing: If going dry is hard, even going “damp” has benefits too.
These findings are from studies that followed tens to hundreds of thousands of people over time, tracking habits and medical conditions as they evolve. These types of studies can’t prove that one habit causes cancer. But epidemiologists use the information to calculate how much a given factor increases or decreases the odds of an outcome – that’s why the result is a risk of cancer associated with the habit.
The reason we do these studies is because for some risk factors and outcomes like cancer, a randomized controlled trial would be unethical and infeasible to perform. So researchers look for dose-dependent patterns that replicate again and again in humans and rely on things like animal research for more clues. This often adds up to a picture that cannot be ignored.
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What I want my patients to know
My patients often think that colonoscopies are done to detect cancers.
That’s not why we do them. We do colonoscopies to prevent cancer.
Yes, of course, colonoscopies detect cancers too, but our big picture goal is to find small pre-cancerous growths called polyps. About 5-10 percent of polyps will go on to become full-blown cancer, and so we remove polyps before they ever turn into a problem. Because of this unique opportunity to intervene early – when people are still young and healthy – colonoscopies prevent cancers and save lives.
So if nothing else, do just this if you’re 45 years or older and due (or younger if you have a family history): schedule that colonoscopy, and start 2026 with your health in mind.