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Cancer Prevention Diet

How to Lower Your Risk with Cancer-Fighting Foods

Woman feeding man broccoli

Whether you have a history of cancer in your family, or are currently battling the disease, lifestyle factors, including your diet, can make a huge difference in helping you fight off cancer. Some foods actually increase your risk of cancer, while others support your body and strengthen your immune system. By making smart food choices, you can protect your health, feel better, and boost your ability fight off cancer and other diseases.

The link between cancer and diet

Not all health problems are avoidable, but you have more control over your health than you may think. Research shows that a large percentage of cancer-related deaths are directly linked to lifestyle choices such as smoking, drinking, a lack of exercise, and an unhealthy diet. Avoiding cigarettes, limiting alcohol, reaching a healthy weight, and getting regular exercise are a great start to preventing cancer. But to best support your health, you also need to look at your eating habits.

What you eat—and don’t eat—has a powerful effect on your health, including your risk of cancer. Without knowing it, you may be eating many foods that fuel cancer, while neglecting the powerful foods and nutrients that can protect you. For example, a daily serving of processed meat increases your risk of colorectal cancer, whereas eating soy foods such as tofu or edamame can help reduce your risk of breast cancer and eating more fruits and vegetables can lower your risk for a variety of common cancers. By making small changes to your diet and behaviors, you can lower your risk of disease. And if you’ve already been diagnosed, eating a nutritious diet can help support your mood and health during this challenging time.

Focus on fruits and vegetables

While there’s no single food you can eat to prevent or fight cancer on its own, a balanced plant-based diet filled with a variety of vegetables, fruits, soy, nuts, whole grains, and beans can help lower your risk for many types of cancer. Eating a colorful variety gives you the best protection. Plant-based foods are rich in nutrients that boost your immune system and help protect against cancer cells. Fruits and vegetables are the best sources of antioxidants such as beta-carotene, vitamin C, vitamin E, and selenium. These powerful vitamins can protect against cancer and help the cells in your body function optimally.

There is also evidence that plant-based foods may be effective at preventing specific cancers. For example:

  • Diets high in fruit may lower the risk of stomach and lung cancer.
  • Eating vegetables containing carotenoids, such as carrots, Brussels sprouts, and squash, may reduce the risk of lung, mouth, pharynx, and larynx cancers.
  • Diets high in non-starchy vegetables, such as broccoli, spinach, and beans, may help protect against stomach and esophageal cancer.
  • Eating oranges, berries, peas, bell peppers, dark leafy greens and other foods high in vitamin C may also protect against esophageal cancer.
  • Foods high in lycopene, such as tomatoes, guava, and watermelon, may lower the risk of prostate cancer.

The less processed these plant-based foods are—the less they’ve been cooked, peeled, mixed with other ingredients, stripped of their nutrients, or otherwise altered from the way they came out of the ground—the better.

How to add more cancer-fighting fruits and veggies to your diet

There are many ways to add plant-based foods to your diet. A nice visual reminder is to aim for a plate of food that is filled at least two-thirds with whole grains, vegetables, beans, or fruit. Dairy products, fish, and meat should take up no more than a third of the plate.

Keep in mind that you don’t need to go completely vegetarian. Instead, focus on adding “whole” foods, which are foods close to their original form. Just as important, try to minimize or reduce the amount of processed foods you eat. Eat an apple instead of drinking a glass of apple juice, for example. Or enjoy a bowl of oatmeal with raisins instead of an oatmeal raisin cookie.

Breakfast: Add fruit and a few seeds or nuts to your whole grain, low-sugar breakfast cereal (such as oatmeal).

Lunch: Eat a big salad filled with your favorite beans and peas or other combo of veggies. Always order lettuce and tomato (plus any other veggies you can) on your sandwiches, which should be made with whole grain bread. Have a side of veggies like carrots, sauerkraut, or fruit.

Snacks: Fresh fruit and vegetables. Grab an apple or banana on your way out the door. Raw veggies such as carrots, celery, cucumbers, jicama, peppers, etc. are great with a healthy dip such as hummus. Keep trail mix made with nuts, seeds, and a little dried fruit on hand.

Dinner: Add fresh or frozen veggies to your favorite pasta sauce or rice dish. Top a baked potato with broccoli and yogurt, sautéed veggies, or with salsa. Replace creamy pasta sauces with sautéed vegetables or tomato sauce made with healthy olive oil.

Dessert: Choose fruit instead of a richer dessert. Or a single square of dark chocolate.

Why fruits and vegetables are cancer-fighting powerhouses

It comes down to this: Fruit and vegetables have less unhealthy fat, more fiber, and more cancer-fighting nutrients. These three elements work together to support your immune system and help your body fight off cancer.  Currently, most people are falling short of the recommended daily minimum of five servings of fruit and vegetables. In fact, most of us need to double the amount we currently eat to stay healthy and help prevent or fight cancer.

Fill up on cancer-fighting fiber

Another benefit of eating plant-based foods is that it will also increase your fiber intake. Fiber, also called roughage or bulk, is the part of plants (grains, fruits, and vegetables) that your body can’t digest. Fiber plays a key role in keeping your digestive system clean and healthy. It helps keep food moving through your digestive tract, and it also moves cancer-causing compounds out before they can create harm. Eating a diet high in fiber may help prevent colorectal cancer and other common digestive system cancers, including stomach, mouth, and pharynx.

Fiber is found in fruits, vegetables, and whole grains. In general, the more natural and unprocessed the food, the higher it is in fiber. There is no fiber in meat, dairy, sugar, or “white” foods like white bread, white rice, and pastries. As you up your fiber intake, make sure to drink plenty of water, as fiber absorbs water.

Simple ways to add more fiber to your diet:

  • Use brown rice instead of white rice
  • Substitute whole-grain bread for white bread
  • Choose a bran muffin over a croissant or pastry
  • Snack on popcorn instead of potato chips
  • Eat fresh fruit such as a pear, a banana, or an apple (with the skin)
  • Have a baked potato, including the skin, instead of fried potatoes
  • Enjoy fresh carrots, celery, or bell peppers with a hummus or salsa, instead of fried chips
  • Use beans instead of always using ground meat in chili, casseroles, tacos, and even burgers (bean burgers can taste great)
  • Drink plenty of water. Fiber absorbs water so the more fiber you add to your diet, the more fluids you should drink. Water is also essential for fighting cancer. It stimulates the immune system, removes waste and toxins, and transports nutrients to all of your organs.
High-fiber, cancer-fighting foods

Whole grains: whole-wheat pasta, raisin bran, barley, oatmeal, oat bran muffins, popcorn, brown rice, whole-grain or whole-wheat bread

Fruit: raspberries, apples, pears, strawberries, bananas, blackberries, blueberries, mango, apricots, citrus fruits, dried fruit, prunes, raisins

Legumes: lentils, black beans, split peas, lima beans, baked beans, kidney beans, pinto, chick peas, navy beans, black-eyed peas

Vegetables: broccoli, spinach, dark green leafy vegetables, peas, artichokes, corn, carrots, tomatoes, Brussels sprouts

Cut down on red and processed meat

Why does there appear to be a link between some types of meat and cancer risk? First, meat lacks fiber and other nutrients that have been shown to have cancer-protective properties. Secondly, industrially-raised meat in some countries, such as the U.S., often contains antibiotics and hormones and the animals may have been raised on feed containing GMOs, markers for an increased cancer risk. 

Most red meat also contains saturated fat, although the health consequences of that are debated in the nutrition world. While many health organizations maintain that eating saturated fat from any type of meat can compromise your health, other experts suggest that saturated fat from organic, grass-fed meat doesn’t pose the same health risks as meat from industrially-raised animals.

Nutrition experts tend to agree that processed meats such bacon, sausages, hotdogs, pepperoni, and salami contain the highest cancer risk, likely due to the nitrate preservatives or other substances used in the processing of the meat.

Making healthier meat and protein choices

You don’t need to cut out meat completely and become a vegetarian. But most people consume far more industrially-raised or processed meat than is healthy. You can cut down your cancer risk substantially by reducing the amount of animal-based products you eat, choosing healthier meats, and substituting more fruit and vegetables in your diet.

Eat red meat less often. Try replacing it with fish, poultry, or vegetarian sources of protein for some dishes.

Reduce the portion size of meat in each meal. The portion should be able to fit in the palm of your hand.

Use meat as a flavoring or a side, not the main focus of a meal. You can use a little bit of meat to add flavor or texture to your food, rather than using it as the main element.

Add beans and other plant-based protein sources to your meals.

Avoid processed meats such as hotdogs, sausage, deli meats, and salami.

Select organic meat. Organic livestock must have access to the outdoors and be given organic feed, free of GMOs. They may not be given antibiotics, growth hormones, or any animal-by-products.

Choose your fats wisely

Eating a diet high in fat increases your risk for many types of cancer. But cutting out fat entirely isn’t the answer, either. In fact, some types of fat may actually protect against cancer. The trick is to choose your fats wisely and eat them in moderation.

Avoid fats that increase cancer risk – The most damaging type of fat is trans fat. Also called partially hydrogenated oils, trans fats are created by adding hydrogen to liquid vegetable oils to make them more solid and less likely to spoil—which is very good for food manufacturers, and very bad for you. While some saturated fats—such as from whole milk dairy and eggs—may have health benefits, unhealthy saturated fats from fast and fried foods can increase cancer risk.

Add fats that decrease cancer risk – The best fats are unsaturated fats, which come from sources such as olive oil, nuts, and avocados. Also focus on omega-3 fatty acids, which fight inflammation and support brain and heart health. Good sources include salmon, tuna, and flaxseeds.

Tips for choosing cancer-fighting fats and avoiding the bad
Limit fast food, fried foods, and packaged foods, which tend to be high in trans fats and unhealthy saturated fat. This includes foods like pizza, potato chips, cookies, crackers, French fries, and doughnuts.
Eat fish once or twice a week. Good choices include wild salmon, sardines, herring, and sablefish (black cod.
Cook with olive oil instead of vegetable oil or other unsaturated oil unless it’s cold-pressed. Only cold-pressed oils are made without the use of high heat or toxic chemicals.
Check the ingredient list on food labels and avoid anything with “hydrogenated” or “partially hydrogenated” oils, which are usually found in stick margarines, shortenings, salad dressings, and other packaged foods, even if they claim to be trans fat-free.
Add nuts and seeds to cereal, salads, soups, or other dishes. Good choices include walnuts, almonds, pumpkin seeds, hazelnuts, pecans, and sesame seeds.
Use flaxseed oil in smoothies, salad dressings, or mixed in snacks such as applesauce. But do not cook with flaxseed oil, as it loses its protective properties when heated.

Prepare your food in healthy ways

Choosing healthy food is not the only important factor. It also matters how you prepare and store your food. The way you cook your food can either help or hurt your anti-cancer efforts.

Boosting the cancer-fighting benefits of food

Here are a few tips that will help you get the most benefits from eating all those great cancer-fighting foods, such as fruit and vegetables:

Eat at least some raw fruits and vegetables. These have the highest amounts of vitamins and minerals, although cooking some vegetables can make the vitamins more available for our body to use.

When cooking vegetables, steam until just tender using a small amount of water. This preserves more of the vitamins. Overcooking vegetables removes many of the vitamins and minerals. If you do boil vegetables, use the cooking water in a soup or another dish to ensure you’re getting all the vitamins.

Wash all fruits and vegetables. Use a vegetable brush for washing. Washing does not eliminate all pesticide residue, but will reduce it. Choose organic produce if possible, grown without the use of pesticides or GMOs.

Flavor food with immune-boosting herbs and spices. Garlic, ginger, and curry powder not only add flavor, but they add a cancer-fighting punch of valuable nutrients. Other good choices include turmeric, basil, rosemary, and coriander. Use them in soups, salads, casseroles, or any other dish.

Tips for cutting down on carcinogens

Carcinogens are cancer-causing substances found in food. Carcinogens can form during the cooking or preserving process—mostly in relation to meat—and as foods start to spoil. Examples of foods that have carcinogens are cured, dried, and preserved meats (e.g. bacon, sausage, beef jerky); burned or charred meats; smoked foods; and foods that have become moldy. Here are some ways reduce your exposure to carcinogens:

Do not cook oils on high heat. Low-heat cooking or baking (less than 240 degrees) prevents oils or fats from turning carcinogenic. Instead of deep-frying, pan-frying, and sautéing, opt for healthier methods such as baking, boiling, steaming, or broiling.

Go easy on the barbecue. Burning or charring meats creates carcinogenic substances. If you do choose to barbecue, don’t overcook the meat and be sure to cook at the proper temperature (not too hot).

Store oils in a cool dark place in airtight containers, as they quickly become rancid when exposed to heat, light, and air.

Choose fresh meats, ideally organic and grass-fed, instead of processed meat that has been cured, dried, preserved, or smoked.

Avoid foods that look or smell moldy, as they likely contain aflatoxin, a strong carcinogen. Aflatoxin is most commonly found on moldy peanuts. Nuts will stay fresh longer if kept in the refrigerator or freezer.

Be careful what you put in the microwave. Use waxed paper rather than plastic wrap to cover your food in the microwave. And always use microwave-safe containers.

The five worst foods to grill

  • Chicken breast, skinless, boneless, grilled, well done
  • Steak, grilled, well done
  • Pork, barbecued
  • Salmon, grilled with skin
  • Hamburger, grilled, well done

Source: Physicians Committee for Responsible Medicine

What about GMOs, pesticides, and cancer risk?

Genetically Modified Organisms (GMOs) are plants or animals whose DNA has been altered in ways that cannot occur in nature or in traditional crossbreeding, most commonly in order to be resistant to pesticides or produce an insecticide. While the U.S. Food and Drug Administration (FDA) and the biotech companies that engineer GMOs insist they are safe, many food safety advocates point out that these products have undergone only short-term testing to determine their effects on humans.

Some animal studies have indicated that consuming GMOs may cause certain types of cancer. Since most GMOs are engineered for herbicide tolerance, the use of toxic herbicides like Roundup has substantially increased since GMOs were introduced. Some studies have indicated that the use of pesticides even at low doses can increase the risk of certain cancers, such as leukemia, lymphoma, brain tumors, breast cancer, and prostate cancer. However, research into the link between GMOs, pesticides, and cancer remains inconclusive.

If you're in doubt about GMOs and pesticides, buy organic or local foods

In most countries, organic crops contain no GMOs and organic meat comes from animals raised on organic, GMO-free feed. Locally grown produce is less likely to have been treated with chemicals to prevent spoilage.

For more, read Organic Foods: All You Need to Know

Cancer prevention: The bottom line

Research shows that about a third of the most common cancers are preventable through changes in diet and lifestyle.

10 Ways to reduce your cancer risk

1. Be as lean as possible without becoming underweight. Weight gain, overweight and obesity increases the risk of a number of cancers, including bowel, breast, prostate, pancreatic, endometrial, kidney, gallbladder, esophageal, and ovarian cancers.

2. Be physically active for at least 30 minutes every day. Physical activity decreases the risk of colon, endometrial, and postmenopausal breast cancer. As fitness improves, aim for 60 minutes or more of moderate, or for 30 minutes or more of vigorous, physical activity every day.

3. Avoid sugary drinks and limit comsumption of energy-dense food. Foods that are high in fats, added sugars, and/or low in fiber, such as many fast and convenience foods, as well as sodas and energy drinks, promote weight gain that is associated with a higher cancer risk.

4. Eat more of a variety of vegetables, fruits, whole grains, and pulses such as beans.

5. Limit consumption of red meats (such as beef, pork, and lamb) and avoid processed meats.

6. Limit alcoholic drinks. Limit consumption to no more than two drinks a day for men and one drink a day for women.

7. Limit consumption of salt and avoid moldy grains and cereals. Limit consumption of processed foods with added salt to ensure an intake of less than 2.4g sodium a day. Do not eat moldy cereals (grains) or pulses (legumes).

8. Where possible, aim to meet nutritional needs through diet alone, instead of using supplements to try and protect against cancer.

9. It is best for mothers to breastfeed exclusively for up to 6 months and then add other liquids and foods. Babies who are breastfed are less likely to be overweight as children or adults.

10. After treatment, cancer survivors should follow the recommendations for cancer prevention. Follow the recommendations for diet, healthy weight, and physical activity from your doctor or trained professional.

Source: World Cancer Research Fund International

Related HelpGuide articles

Resources and references

Cancer prevention and cancer-fighting foods

Cancer Trends Progress Report: Prevention – Learn about the relationship between human behaviors such as diet and cancer, with links to fact sheets on  Fruit and Vegetable Consumption, Red Meat Consumption, and  Fat Consumption. (National Cancer Institute)

The Anti-cancer Diet – This article gives very detailed information on 12 dietary recommendations that lower your cancer risk. (Ask Dr. Sears)

Cancer Prevention: Ask the Expert: Nutrition – Brief answers to some common questions about the relationship between diet and cancer. (Michigan State University)

Cancer Prevention Recommendations – Recommendations to help prevent some of the most common cancers. (World Cancer research Fund International)

Foods that Fight Cancer – Information on specific foods and their role in protecting your health. (American Institute for Cancer Research)

Cancer Facts: Meat Consumption and Cancer Risk – Information on the relationship between eating meat and how that affects your risk for cancer. (The Cancer Project)

Cancer prevention and the immune system

Strengthening Immune Function: Choose Immune-Boosting Foods – This article has information on immune boosting foods and includes recipes as well as information on specific nutrients. (NutritionMD)

Where to find farmer’s markets

Eat Well Guide – Find local, organic, sustainable food from farms, markets, restaurants and more in the U.S. and Canada. (Eat Well Guide)

Local Harvest – Find farmers' markets, family farms, and other sources of sustainably grown food in your area of the U.S. (Local Harvest)

Sustainable seafood choices

NRDC Walletcard (PDF) – This downloadable walletcard from The Natural Resource Defense Counsel lists the mercury levels in fish and offers recommendations for how often to eat those types of fish.

Seafood Watch – Get recommendations on which seafood to buy and which to avoid. Includes a free iPhone or Android app you can download. (Monterey Bay Aquarium)

Authors: Maya W. Paul, Melinda Smith, M.A., and Lawrence Robinson. Last updated: December 2016.