Doing a search for foods that prevent cancer is not for the faint of heart: You get results that skew more Wild West than American Medical Association.
Cleveland Clinic is a non-profit academic medical center. Advertising on our site helps support our mission. We do not endorse non-Cleveland Clinic products or services. Policy
“The first things that tend to pop up are lists of foods you should eliminate because they cause cancer to grow. But we shouldn’t be fearful of food,” says cancer dietitian Joseph Dowdell, RDN, LD. “Instead, take a step back and look at the big picture. That will allow you to focus on the diet changes that will have the most impact.”
Dowdell explains what’s currently known about diet and cancer risk — and how to eat to lower yours.
The connection between diet and cancer
While food has not been shown to prevent cancer, diet plays a big role in cancer prevention. According to the American Cancer Society, having excess weight or obesity is a risk factor for many cancers, including:
- Breast cancer (among women who have gone through menopause).
- Colon and rectal cancer.
- Endometrial cancer (cancer in the lining of the uterus).
- Esophageal cancer.
- Kidney cancer.
- Liver cancer.
- Ovarian cancer.
- Pancreatic cancer.
- Stomach cancer.
- Thyroid cancer.
- Multiple myeloma (white blood cell cancer).
- Meningioma (a tumor in the lining of the brain and spinal cord).
And at least 18% of all cancers and about 16% of cancer deaths are related to:
- Excess body weight.
- Physical inactivity.
- Alcohol consumption.
- Poor nutrition.
“Food can help prevent many of the chronic conditions that increase your risk of cancer,” says Dowdell. “Genetics and other health conditions can impact cancer prevalence as well, but those are usually out of our control. Obesity is something we can control through food and exercise.”
Six ways to reduce cancer risk with diet
To help reduce cancer risk, Dowdell says it’s all about balance to maintain a healthy weight. He recommends:
1. Go Mediterranean
A Mediterranean diet focuses on eating plant-based foods. It includes:
- Fruits and vegetables.
- Whole grains.
- Healthier fats, such as extra virgin olive oil, nuts and seeds.
- Lean sources of protein, such as poultry, fish and legumes.
It also involves limiting:
- Red meat.
- High-fat dairy.
- Added sugars.
- Saturated fats.
Dowdell says that the Mediterranean diet has been linked to cancer prevention and other positive impacts on long-term health. And high-fiber diets like the Mediterranean diet are associated with a decreased risk of colon cancer.
2. Eat at least five to nine servings of fruits and vegetables each day
“Eat the rainbow” is a good rule of thumb, according to The American Cancer Society, which reports that the pigment that gives fruits and vegetables their color has ingredients that may reduce cancer risk. “And all those vitamins and minerals play a role in cell health, keeping our body functioning at its peak levels,” says Dowdell.
To incorporate more plants into your diet, try to:
- Eat at least three different colors of fruits and vegetables each day.
- Make 50% of your plate fruits and vegetables. Split the other half between lean or plant-based proteins and whole grains.
3. Limit added sugars
When it comes to cancer, some view sugar as public enemy No. 1. But Dowdell says there’s more to it. “While sugar fuels cancer cells, it fuels us, too. It helps our organs function properly. So it is nearly impossible to eliminate sugar. But the problem isn’t foods with natural sugar. It’s the added sugars that can lead to obesity and heart disease, which increase your risk of cancer,” he says.
Watch out for the usual suspects — sugary beverages, candies and desserts — as well as “healthier” foods that contain added sugars:
- Granola bars.
- Salad dressings.
“Food is powerful. Some use it for comfort. Others use it for fuel or to be social. So it’s important to still embrace those things but in the healthiest way possible,” Dowdell adds. “You can eat that piece of cake on your birthday or indulge a little during a barbecue. Having an occasional treat is perfectly fine. It’s when those practices happen daily that negative long-term effects come into play.”
4. Cut down on alcohol
Alcohol use is associated with an increased risk of esophageal, throat and breast cancer. People who drink a lot of beer also have an increased risk of rectal cancer. And people with alcohol use disorder have increased incidences of liver cancer.
5. Go easy on the salt
Avoid cured, smoked and nitrite-preserved foods. International studies reveal higher incidences of stomach and esophageal cancers in people who consume large amounts of these products.
6. Take vitamin D supplements (1,000 to 2,000 IU daily)
Low levels of vitamin D are associated with an increased risk of breast, colon and pancreatic cancer.
Healthy eating: Start small for big change
If your diet is currently more fast-food fodder than plant-based paradigm, Dowdell says to start small. “Making any change is difficult. But setting small, achievable goals makes big goals much easier to accomplish.”
- Reduce portion size: Try to reduce portion sizes first before eliminating unhealthy foods.
- Reduce unhealthy foods incrementally: “If you’re used to drinking four sodas a day, shoot for one a day for the next week,” Dowdell says. “And then the following week, shoot for one every other day and see how that goes. Slowly cut down even more. You can make drastic health impacts without feeling deprived.”
But Dowdell has an important reminder: “Everyone’s body reacts to food differently.”
“While all of these are healthy guidelines, nutrition should be individualized. If you have digestive issues, for example, you should seek medical help,” Dowdell adds. “And always use reliable sources of information like the Academy of Nutrition and Dietetics, the American Heart Association and the American Cancer Society.”