Cancer is a leading cause of death worldwide, and while survival rates are on the rise, many cases are preventable. In fact, more than 40 percent of both cancer cases and deaths in the United States are tied to controllable risk factors, according to the American Cancer Society (ACS).
Of course, some risks are beyond our control, such as age and genes. But we’re able to influence many others, such as wearing sunscreen and avoiding tobacco. We can also control cancer risk factors related to diet, including obesity, alcohol consumption, and the types of food we eat.
A May 2019 study published in Journal of the National Cancer Institute Cancer Spectrum estimated that diet-related factors accounted for 80,110—or 5.2 percent—of new invasive cancers (those that have spread beyond the initial tumor) in adults in 2015. Alcohol consumption may contribute a similar percentage to cancer risk.
Read on to learn about foods linked to an increased risk for cancer, and foods that may help prevent cancer.
Foods associated with greater cancer risk
When it comes to diet and cancer, eating patterns, not just individual foods, may make a difference.
“One specific food is not going to cause cancer. But as part of an overall pattern, what you eat can increase your risk,” says Kelly K. Rashid, RDN, CSO, a clinical dietitian and certified specialist in oncology nutrition in Fort Lauderdale, Florida.
Still, certain types of food are linked to a greater cancer risk, so it’s best to take steps to limit or avoid them. These include the following.
Processed meats
Processed meats are meats that are preserved via salting, curing, smoking, or other, similar methods. These meats include bacon, hot dogs, ham, sausage, and deli slices, among other items.
“Processed meats are one of the foods we have the most research on when it comes to cancer of the colon [the large intestine] and rectum [the last several inches of the large intestine],” Rashid says.
Studies tie eating too much processed meat to a 20- to 30-percent higher risk of developing colorectal cancer. “Even a small amount increases your risk,” Rashid adds. For this reason, the ACS recommends eating processed meat sparingly, if at all.
The preservation methods used to make these products may contribute to the risk. Another factor: Processed meats are often red meats. (More on that next.)
Red meat
Red meats such as beef, veal, lamb, and pork are also associated with cancer. The connection may be related to:
- The saturated fat content of many red meats. Eating too much saturated fat can lead to inflammation and weight gain. Being overweight or obese is a major risk factor for several cancers, including those of the esophagus, breast, colon, rectum, stomach, pancreas, and liver.
- The heme iron found in red meat, which may lead to the production of cancer-causing compounds
- Carcinogens (cancer-causing agents) that form when the meat is cooked at high temperatures or charred on the grill
Eating too much red meat is also tied to a higher risk of heart disease. That’s why many leading health organizations, including the ACS and American Heart Association (AHA), recommend opting for lean proteins instead, such as chicken breast, fish, beans, and tofu. If you do eat red meat:
- Choose leaner cuts and trim off fat when you can.
- Be aware of your overall saturated fat intake. The AHA recommends no more than 13 grams for a person who eats 2,000 calories each day.
- Eat moderate portions. A single serving is 3 ounces, or about the size of a deck of cards.
- Limit cooking time if you’re grilling. Pre-cooking in a microwave, oven, or stove can help.
Alcohol
Experts believe alcohol is responsible for about 5 percent of cancer cases. Even one alcoholic drink per day raises the risk of many types, including cancer of the breast, colon, rectum, esophagus, throat, and mouth. And the more you drink, the higher your risk.
There are several potential explanations for the link. It’s believed that the ethanol in alcoholic drinks may directly cause cancer. Alcohol may also increase the ability of other carcinogens to enter your body’s cells and cause changes that lead to cancer. It could raise levels of the hormone estrogen, as well, and influence your body’s ability to absorb folate, a key nutrient that helps protect against colon cancer.
Your genes, medical history, weight, and lifestyle will also play roles. But when it comes to cancer prevention, avoidance of alcohol is the best bet. If you do drink alcohol, don’t exceed guidelines for light or moderate drinking: No more than two drinks daily for men, and one drink per day for women.
Sugar
Sugar has not actually been found to directly increase cancer risk, but there is an indirect link. “Sugar in general does not provide any nutritional value, and it causes obesity—and obesity is linked to at least 12 different types of cancer,” Rashid explains.
“If you drink a sugary beverage on a special occasion, is it going to cause you cancer? No,” Rashid adds. “But the risk increases if you consume excess calories and sugar, and it causes obesity. There are also a number of other health concerns associated with sugar-sweetened beverages.” These include a higher risk of type 2 diabetes and heart disease.
The ACS advises limiting added sugar. The AHA recommends that it make up no more than 6 percent of your calorie intake each day. For many healthy adult men, that works out to around 150 calories daily. For women, it’s 100 calories.
Foods linked to lower cancer risk
While some foods are tied to higher cancer risk, many others are tied to lower risk—and you may be eating them already.
“The recommendations for a healthy, cancer-prevention diet are not really different at all from your standard dietary recommendations,” Rashid points out. They include the following foods, many of which come from plant sources.
Whole grains
Whole grains are essential sources of dietary fiber. Not getting enough fiber can increase your cancer risk. In fact, a low-fiber diet is associated with roughly 10 percent of all colorectal cancer cases, according to the ACS.
Eating whole grains such as brown rice, oatmeal, and whole wheat bread can ensure you get enough fiber, along with other key nutrients that could help lower the risk of cancer. The ACS recommends eating whole grains as part of a healthy overall diet, and the AHA advises getting about three servings each day.
Fruits and vegetables
Produce also contains plenty of fiber. Eating a range of colorful fruits and veggies supports healthy weight management, as well, and provides phytochemicals—plant compounds that may reduce the risk of certain cancers, including lung cancer and oral cancers.
“Different color groups have different types of phytochemicals, and they work in different ways to fight off cancer,” says Rashid.
Legumes
Like produce and whole grains, legumes (beans, peas, and lentils) are plant-based foods that are rich in fiber. Legumes are also good sources of protective nutrients like folate, as well as protein, which makes them excellent substitutes for red meat. Try swapping them into soups, stews, chilis, and other main dishes in place of ground beef or pork.
Dairy
“There’s a lot of mixed research with dairy, though with some cancers, it’s now looking like dairy may have a protective effect,” says Rashid. Many experts suggest choosing low-fat or fat-free dairy options.
Fermented dairy products often also contain beneficial bacteria called probiotics, which some research suggests are associated with lower cancer risks. Good sources of these microorganisms include yogurt with live, active cultures and kefir, a drink made from fermented cow's milk. Probiotics are also found in other non-dairy fermented foods like pickles, sauerkraut, and kimchi.
Make healthy choices when you can
You don’t have to give up the foods you love entirely. But it’s good to be aware of which ones to emphasize and which ones to limit. It comes down to variety, portions, and making healthy choices when you can.
“I would never tell someone they can’t ever have certain foods or never use their grill again. Just try to save them for special occasions,” says Rashid. “We want more of a plant-based diet. It doesn’t have to be plant-only, but you should focus on more plant foods and less on processed or animal products.”
