Cancer is not a single disease, but many related diseases that occur within the body. There is no single cause of cancer.
Cancer occurs due to a variety of factors, including some you cannot control, like genetics, and others you can control, like diet and lifestyle. Research shows some foods are associated with a higher risk of certain types of cancers.
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At least 18% of all cancers and about 16% of cancer deaths in the United States are related to excess body weight, physical inactivity, alcohol consumption, and/or poor nutrition.
How Your Diet Impacts Cancer Risk
While no human studies have shown that any single food by itself causes or prevents cancer, research does show that certain foods are associated with increasing or decreasing the risk of developing cancer.
Maintaining a healthy body weight, consuming a healthful diet, and avoiding or limiting alcohol can help reduce the risk of developing or dying from cancer. This includes a healthy eating pattern focusing on nutrient-rich foods and avoiding foods like:
- Highly processed foods
- Red meat
- Refined foods
- Sugary drinks
A Word From Verywell
A diet focusing on fruits, vegetables, and whole grains can help lower cancer risk. Reduce foods like processed meats, refined grains, sugary drinks, and alcohol, and enjoy them in appropriate portions once or twice a month rather than weekly or daily.
Foods That May Cause Cancer
Certain foods, such as processed meats, fried food, sugar and refined carbohydrates, and alcohol, are known to increase the risk of cancer.
Processed Meats
Processed meat has been salted, cured, fermented, smoked, or undergone other steps to enhance flavor or improve how long it can be stored.
Processed meat is classified as a group 1 carcinogen because certain ingredients in it are known to cause cancer. Some meat-processing methods, such as curing, involve adding nitrates and nitrites, which can lead to the formation of potentially cancer-causing chemicals in the meat.
Higher processed meat consumption is strongly associated with an increased risk of developing colorectal cancer. Research shows the association is stronger for bacon and breakfast sausage than for lunch meats, hot dogs, or dinner sausages.
Red Meats
Some compounds and heme iron in red meat are believed to promote the growth of cancerous tumors. Eating red meat is strongly linked with an increased risk of colorectal cancer, with risk rising with a higher quantity and frequency of eating red meat. How red meat is cooked, such as by grilling, or barbecuing, is also associated with an increased risk of colorectal cancer.
Red meat is also strongly associated with a higher risk of most gastric cancers and breast cancer. Some compounds in red meat have a strong correlation with pancreatic cancer, although more research is needed.
Fried Foods
During the frying process, food and oils undergo chemical changes, forming substances that can potentially cause cancer. Results of studies connecting fried food consumption to increased cancer risks have had mixed results, although fried food is associated with an increased risk of gastric cancer.
Overcooked Foods
Frying or grilling meat, poultry, pork, and fish at high temperatures over an open flame is linked to an increased risk of breast, colon, liver, lung, prostate, and other cancers in animal studies. Cooking these foods at high temperatures produces chemicals that might increase cancer risk.
Grilling certain types of red meat, including steak, hamburgers, pork chops, bacon, and sausages, at high temperatures is linked to an increased risk of colorectal cancer.
Sugar and Refined Carbohydrates
Excess sugar consumption has been linked to the development and progression of certain cancers, including breast, colorectal, and pancreatic cancers. Whether the increased risk is due to weight gain, a known risk factor for cancer, or another reason is not known.
Study results on whether refined carbohydrates raise the risk of certain cancers have been mixed, although these foods can also promote weight gain.
Dairy
Some studies link dairy with an increased risk of premenopausal (the time of life leading up to menopause, when the menstrual cycle completely stops) breast cancer, prostate cancer, and colorectal cancer. However, there is a lack of definitive research linking dairy consumption to increased cancer risk.
Alcohol
Drinking alcohol is known to raise the risk of developing several types of cancers, with the risk increasing the more a person regularly drinks over time. Alcohol raises the risk of cancers of the:
Can Some Foods Lower Your Risk of Cancer?
Consuming certain foods regularly, like whole grains, nuts and seeds, fruits and vegetables, and more are linked to a lower risk of cancer.
Fruits and Vegetables
Fruits and vegetables are full of nutrients that can help protect against cancer and should be part of an overall healthy diet to lower cancer risk. Dark green, red, and orange vegetables and whole fruits in various colors are recommended to protect against cancer.
People whose diets are rich in fruits and vegetables have a lower risk of several cancers, including cancers of the:
Nuts
Nuts contain a high amount of nutrients with anticancer properties. Research shows that consuming 28 grams of nuts daily is associated with a 21% reduction in the risk of dying from cancer.
Beans
There is evidence that the fiber, resistant starch, and other compounds found in pulses (lentils, dry beans, and peas) may all support a healthy gut microbiome and protect against cancer, although more research is needed.
Whole Grains
Whole grains are foods with an entire grain kernel, including the bran, germ, and endosperm. Some whole-grain examples are bulgur (cracked wheat), oatmeal, and brown rice.
Whole grain consumption over time is associated with lower overall cancer risk. Even one serving a day of whole grains may reduce cancer risk, with protection increasing with the number of servings.
Fish
Although there is some evidence that eating fish might reduce the risk of certain cancers, including liver, colon, and breast cancers, there is a lack of solid evidence. More research is needed.
Are There Cancer-Fighting Foods?
If you have cancer, a healthful diet is important because it helps your body function and maintain weight and energy. While the best diet varies, fruits, vegetables, legumes, nuts, seeds, and whole grains are all known to help fight cancer naturally.
What Are the Common Cancer-Causing Chemicals in Foods?
Certain chemicals in foods are linked to helping cause or raising the risk of cancer. They include:
- Acrylamide: A chemical produced when certain vegetables are heated to high temperatures. Primary food sources of acrylamide are French fries, potato chips, crackers, bread, cookies, and breakfast cereals.
- N-nitroso-compounds (NOC) and polycyclic aromatic hydrocarbons (PAH): These chemicals can form when nitrates or nitrites are added to processed meats.
- Heterocyclic amines (HCAs): These chemicals form when muscle meat, including beef, pork, fish, or poultry, is cooked at high temperatures, such as pan frying or grilling over an open flame.
Summary
Several different factors cause cancer. Some foods, such as red or processed meat, alcohol, fried foods, dairy, and more, are known to raise the risk of developing certain cancers. Avoiding these foods might help lower your cancer risk.
Foods such as fruits, vegetables, whole grains, nuts, and seeds, if regularly consumed, may also help reduce the risk of developing cancer. To lower your cancer risk, it's important to maintain an overall pattern of healthy eating with a diet rich in nutrient-dense foods.