8 colon-cancer risk factors, from diet to drinking habits

• Colorectal cancer is a leading cancer diagnosis and on the rise among younger people, studies find.

• You can decrease your risk of colon cancer by eating healthy and exercising, an expert says.

• But uncontrollable factors like genetics make it important to get regular screenings.

Colorectal cancer is the third most common cancer diagnosis in the US, according to the American Cancer Society, and factors like lifestyle, eating habits, and family all play a role in how at risk you might be.

While people over 50 are most at risk, evidence suggests that rates of colon cancer are on the rise among younger people, in part because of some preventable risk factors, including diet.

The best way to protect yourself from colon cancer is proper screening, Dr. Francis Giardiello, Johns Hopkins gastroenterologist, wrote in an online Q&A.

Not all factors in colon cancer are in your control, like genetics and other health conditions, according to Dr. Austin Chiang, gastroenterologist and assistant professor of medicine at Jefferson Health.

"The most well-defined risk factors are specific conditions like inflammatory bowel disease, inherited conditions like Lynch syndrome, or a family history of colon cancer," he told Insider. "However, there are other things that could increase risk such as smoking, frequent consumption of red meat, and obesity."

Making healthy changes to your routine can help manage the risk, according to Anjee Davis, the president of Fight Colorectal Cancer, an advocacy organization for patients with colorectal cancer.

"Getting screened for colorectal cancer is the most effective and most important way to prevent it and reduce your risk. However, there are lifestyle changes that can reduce your risk of polyps and colorectal cancer," she told Insider.

Based on the latest evidence, eating more plant-based foods high in fiber, cutting back on alcohol and red meat, and staying active may be helpful ways to stave off colon cancer, though some factors, like genetics, may be out of your control.

A sedentary lifestyle may increase your risk of colon cancer.

Too much time spent sitting is a risk factor for multiple cancers, including colon cancer, research has found. In contrast, regular exercise can help reduce the risk, Giardiello wrote.

Physical activity seems to have a protective effect, helping to lower the risk of colon cancer, studies suggest. There's also good evidence that cardiovascular fitness is linked to lower risk of getting colon cancer and of dying from colon cancer.

Experts recommend getting a few hours of exercise each week, whether that's walking, playing sports, lifting weights, or anything else that raises your heart rate.

"Increase your physical activity — get at least 150 minutes of moderate-intensity or 75 minutes of vigorous-intensity activity each week," Davis said.

Lack of fiber, fruits, and vegetables in your diet can be bad for gut health.

What you eat is an important factor in your odds of developing colon cancer, and eating lots of fruits and veggies can help, Giardiello wrote.

Produce and whole grains can help you get enough fiber, an important nutrient for preventing chronic illnesses like cancer, evidence suggests.

"Fiber is important because it keeps the digestive system working well, and it lowers inflammation, which can lead to cancer and other diseases," Davis said.

Studies have linked diets lacking in fiber and plant foods — such as the common American diet high in processed food, refined grains, and sugar — to higher risk of cancer, too, Chiang said.

While it's not clear why fiber is so healthy, it also has other benefits linked to adding more fruits and veggies to your diet and cutting unhealthy foods, he added.

"With that in mind, there are good reasons to adopt a high fiber diet aside from colorectal cancer specifically," he said.

Eating well can also help you have better odds of beating cancer if you do get it, Davis said.

"Diet plays a major role in not only preventing cancer, but it affects treatment and survivorship too," Davis said. "There is no one-size-fits-all diet, but there are healthy-eating guides."

No matter your eating style, good goals for cancer prevention are to make plant foods about two-thirds of your plate, according to Davis.

A colorful mix of fruits, veggies, grains, nuts, and seeds can help you get a variety of nutrients and health benefits, she said.

Eating a lot of red meat and saturated fats may increase cancer risk.

While plant foods like veggies seem to be protective against colon cancer, some evidence suggests red and processed meat have the opposite effect, raising your risk, Giardiello wrote.

Processed meat is consistently linked to worse health outcomes for several illnesses, including heart disease and colon cancer.

Red meat is more ambiguous, with some studies suggesting too much may be unhealthy and others indicating it's fine in moderation.

You may not need to cut meat out entirely, but experts suggest limiting your consumption of red meat to a few servings a week and nixing foods like bacon, sausages, and cold cuts.

"If you choose to eat red meat, eat no more than 12 to 18 ounces per week, and avoid processed meats as much as possible," Davis said.

Also be mindful of how you prepare your meats, since evidence suggests high temperatures can increase the level of cancer-causing compounds in the meat.

Heavy drinking is a cancer risk.

There's convincing evidence that moderating your alcohol consumption can help reduce your risk of colorectal cancer, Davis said.

Alcohol is a known carcinogen, or cancer-causing substance, which can raise your risk of multiple types of cancer, according to the American Cancer Society.

What's less clear is how much alcohol is safe. Most experts advise having no more than one alcoholic drink a day for women and no more than two a day for men, according to the US dietary guidelines.

Some studies have found that there is no safe amount of alcohol and even a daily drink or two can increase the risk of cancer.

Smoking is a major preventable risk of cancer.

It's common knowledge that smoking can cause cancer, but it isn't just your lungs that are in danger. It significantly increases your risk of colon cancer as well, Chiang said, and minimizing smoking habits can be preventative.

One of the best things you can do is avoid smoking entirely, or quit, according to Davis.

"Don't smoke, and if you do, stop smoking," she said.

A high BMI is associated with colon cancer.

Body mass index, or the ratio of height to weight, can be another indicator of above-average colon-cancer risk, Davis said.

Multiple studies have found a higher risk of colon cancer is associated with having a BMI above 25 (considered "overweight") or 30 (in the "obesity" range), with some evidence finding nearly double the risk in people with a higher BMI.

As a result, obesity is a factor that should be considered in evaluating colon cancer risk, Chiang said.

BMI is controversial because it's not always an accurate measure of health, and some experts say it contributes to weight stigma and worse healthcare access for people with larger bodies.

But managing your weight may be protective against colon-cancer risk, particularly in conjunction with the other lifestyle changes, like diet, exercise, smoking, and alcohol use, research suggests.

And some evidence indicates how much body fat you have, and where it is, may be an important factor, with belly fat seeming to pose the biggest risk.

"Maintain a healthy body weight," Davis said. "Avoid overall body fat, especially fat around your waist."

Other medical conditions, like type 2 diabetes or gastrointestinal issues, may be risk factors for cancer.

Your overall health, and digestive health, specifically, can influence your odds of developing colon cancer, the experts say.

Inflammatory bowel disease, Crohn's disease, and ulcerative colitis affect the intestines and can make you at higher risk for colon cancer, according to the Centers for Disease Control and Prevention.

Having type 2 diabetes is also linked to a higher risk, independent of other risk factors such as BMI and exercise habits.

Talk to your doctor about your medical history so they can better understand and recommend a prevention plan, Davis said.

"It's important to see a doctor who understands your personal risks and the nuances of colorectal cancer. High-risk patients will need to be screened more often," she said.

Chiang said it's recommended that most adults start screening at age 45, and younger if there are underlying conditions.

"The most important thing is colon cancer is one of the few cancers we actually can prevent by taking out pre-cancerous polyps before they transform into cancer," he said.

Genetics also play a role in cancer risk.

Not all risk factors for colon cancer can be changed, and up to 20% of colon cancers have a hereditary link, Giardiello wrote.

A family history of colon cancer or colon polyps (growths inside the digestive system) can increase your risk of colon cancer.

Black people are also at higher risk of colon cancer, though experts aren't entirely sure why. A 2020 study found Black Americans were significantly more likely to die of colon cancer because they were less likely to get life-saving treatments than their white peers.

Because of genetic and other factors, you can get colon cancer even if you have a healthy lifestyle, so it's still important to be aware of your risk and get screened regularly, according to Davis.

"We have met many patients, especially early-age onset colorectal-cancer patients who followed the lifestyle recommendations for cancer prevention, and they were still diagnosed with colorectal cancer," she said. "Lifestyle changes are important, but they do not replace screening."

Keep an open conversation with your doctor and family to help reduce risks, Chiang said.

"If there's been a family history of colon cancer it would also be important to let everyone in the family know so they can take the appropriate precautions and share that information with their doctors too," he said.

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