It would be great if there were a simple dietary prescription for preventing cancer—if eating one food or skipping another could keep you safe. Unfortunately, the truth about diet and cancer is more complex.
No single food or food group can ward off cancer. And you can't count on protection from dietary supplements either. That said, making good food choices overall may help lower your risk.
"You do have some control over your cancer risk, and eating well is a part of that," says Colleen Doyle, MS, RD, managing director of nutrition and physical activity at the American Cancer Society (ACS).
Scientists are still investigating connections between diet and cancer risk. Some findings suggest nutrients in certain foods may guard against specific types of cancer or that other food choices may raise some risks.
How much we eat also plays a role. Oversized, calorie-rich portions can lead to excess weight, which is estimated to cause 7% of cancer deaths, according to the ACS.
"We know that being overweight increases the risk of a lot of different types of cancer," Doyle says.
What you can do
Here's a look at some healthy dietary habits that may help reduce your cancer risk.
Choose more plant-based foods. Studies suggest diets rich in fruits and vegetables may help protect against a number of cancers, including those of the lung, mouth, esophagus, stomach, and colon.
One way plant foods may help is by providing vitamins, minerals, and antioxidants and phytochemicals—substances that might protect cells from damage that can lead to cancer.
No one knows which nutrients might help most though. So make sure your diet includes a variety of vegetables, fruits, beans and whole grains.
It's also important to get your nutrients from food rather than supplements.
"Nutrients may interact with each other in a synergistic way that just can't be duplicated in a supplement," Doyle says.
In addition to providing nutrients, a diet rich in plant foods may also lower cancer risk by helping people manage their weight.
"We're seeing more and more evidence that people who consume higher amounts of fruits and vegetables have healthier weights," Doyle says.
Limit red and processed meat. Eating too much red meat may increase the risk for colon and possibly prostate cancers. Processed meats, such as hot dogs or bologna, may boost that risk even more.
"There are very clear data that indicate people who eat even relatively small amounts of red or processed meats over time have an increased risk of colon cancer," Doyle says.
Red meat's iron or fat content might contribute to the risk. Cancer-causing compounds may also be formed when red meat is cooked over high heat, charred or grilled over flames.
With processed meats, smoking, curing, salting or adding preservatives may help explain the link, according to the American Institute for Cancer Research.
Try replacing red meat with healthier protein options such as fish, poultry or beans sometimes. If you do eat red meat, choose lean portions and limit your intake to three portions (totaling 12 to 18 ounces) per week.
Know the risks of alcohol. Alcohol is linked to an increased risk of breast, oral, esophageal, colon and other cancers.
The big picture
When it comes to reducing cancer risk, your efforts should go beyond diet. Here are a few additional habits that can help you avoid the disease:
- Don't smoke. Smoking increases the risk for a variety of cancers, including those of the lungs, throat, mouth, esophagus, bladder and cervix.
- Stay active. Exercising may reduce the risk of breast, colon and other cancers—independently and by promoting weight control.
- Get screened. Finding cancer or precancerous changes early is among the best ways to guard against some types of cancer. Ask your doctor about recommended screenings.
For more information on what you can do to reduce your risk for cancer, talk to your healthcare provider.