Good News: Diet Can Help Prevent Cancer

Can eating the right foods actually help prevent cancer? According to Dena McDowell, MS, RD, a registered dietician for the Froedtert & Medical College of Wisconsin Cancer Center, the answer is yes. Studies indicate that if you eat a well-balanced diet and maintain other healthy habits like exercising and eliminating tobacco, it will help reduce your risk of cancer by as much as 70%.

"There is a strong connection between what you eat and whether you develop cancer in your lifetime," says McDowell. "The American Cancer Society Nutrition Guidelines call for a diet that is as plant-based as possible. That means more fruits, vegetables and legumes," she said. "I tell people that when they are in the grocery store, shop the perimeter of the store first. That is where the fresh produce, dairy products and meats are located."

Mix It Up
It is important to eat a wide variety of foods each day, such as fruits and vegetables, whole grains or cereals, lean meats, poultry without skin, and fish, legumes (beans), and low-fat dairy products. "Most of us eat a diet that is too low in fiber. I recommend increasing the amount of fiber in your diet by eating more fruit, vegetables, whole grain breads and cereals, and legumes," McDowell said.

Just how much of the various foods should you eat? "There is a new food guide pyramid that helps you decide how much of each food group to eat," McDowell said. "Try to include vegetables and fruits at every meal and as snacks." You can take a look at the new pyramid and other useful information including a plan for your daily needs based on age and gender by going to mypyramid.gov (free registration is required for using some areas of the website.)

As for carbohydrates, McDowell suggests choosing whole-grain, complex carbohydrates. Despite their popularity, she is not a proponent of low-carbohydrate diets. "If you don't eat carbohydrates, you won't have any energy. However, I do recommend avoiding white bread, white potatoes, and pasta, otherwise known as refined carbohydrate foods," she said.

Foods to Choose
With all of the food choices available to us, how can you tell which ones are the best? "Ten foods have been labeled 'super foods' by the American Cancer Society because of their cancer-fighting abilities," McDowell said. Try to incorporate these foods into your diet whenever you can:

• Berries (raspberries, blueberries, etc.)
• Broccoli
• Cold water fish (salmon, tuna)
• Flax seed (use as a food additive or in bread)
• Legumes ("Go meatless at least once a week," McDowell said.)
• Low-fat dairy products
• Spinach (fresh)
• Soy foods such as tofu; although "You may want to avoid soy foods if you have breast cancer. There is a potential relationship between the two," McDowell said.
• Sweet potatoes/pumpkin/squash (rich in Vitamin A or Beta Carotene)
• Walnuts (rich in Omega 3 fatty acids)

Portion Size Counts
Determining serving sizes can be confusing - and people tend to underestimate how much they're actually eating. What counts as a serving? Following are some examples:

• 1 medium piece of fruit
• 2 cups leafy greens
• 1 cup fresh or frozen fruits and vegetables
• 1 slice bread, ½ hamburger bun, ½ bagel
• ½ cup pasta, rice or mashed potato
• ½ cup cooked cereal
• 1 oz. dry cereal
• 3 oz. cooked meat, poultry or fish
• 3 slices of thin sliced deli meats
• ½ cup beans
• 1/3 cup nuts

"Buy fresh food as often as possible. Learn to read product labels because they can help you choose foods that are better for you," McDowell said.

Cancers Linked to Diet
Several types of cancer are directly linked to diet, according to research. In the typical American's diet, about 40% of calories come from fat. "Some evidence indicates that diets high in fat might increase the risk of cancers of the colon, breast, prostate, and the lining of the uterus (the endometrium). Diets low in fat may reduce these risks while they help to control weight and also reduce risk of heart attack and stroke," McDowell said.

Obesity is also a risk factor for kidney, pancreatic, and oral/esophageal cancers. "To reduce the fat in your diet, choose more low-fat or fat-free dairy, legumes, lean meats, poultry or fish. Skip rich sauces that are made with butter, cream or mayonnaise, and limit fried foods," McDowell said.

Diets rich in foods containing vitamin A, vitamin C, and beta carotene may also reduce the risk of certain cancers, such as bladder, breast, colorectal, and stomach cancer. Many vegetables and fruits contain vitamins A and C and beta carotene, such as dark green leafy vegetables, red, yellow and orange vegetables and fruits and citrus fruits and juices.

Using Herbs and Supplements
"The supplement market is a multibillion dollar industry that is not regulated by the FDA (Food and Drug Administration), therefore, consumers must be well informed," McDowell said. To make the best choice, look for the USP label on the product, which means it has been standardized; take no more than 150% of the daily value of any given nutrient; look at current research regarding the supplement and make sure the research is peer reviewed - not just a claim that the company has made. "Make sure to inform your doctor of any supplements that you are taking, and talk to your pharmacist about the possibility of any nutrient-drug interactions," she said.

Changing Your Habits
The benefits of a healthy diet rich in fruits, vegetables and grains are numerous. "Not only will you decrease your risk of cancer, you will be able to better manage your weight, and reduce your risk of heart disease," McDowell said.

Speaking of managing your weight, McDowell recommends trying to lose some weight if you are overweight. Most importantly, get some exercise. "A goal for adults is to exercise for 60 minutes or more five days a week. Children and teens should get sixty minutes every day," she said.

If you drink alcohol, limit your consumption to one drink a day for women and two drinks a day for men. "Avoid mixed drinks with sugar or juice. Instead, choose dark beers and wines," McDowell said. "If you don't drink, don't start."

Likewise, don't smoke. Tobacco causes about one-third of all cancer deaths - more than all the other reliably known cancer causing agents added together, according to the National Institutes of Health. Heart disease and emphysema caused by smoking kill even more people than cancer.

It takes years to form bad habits, so don't expect to change them overnight. Instead, consider some ongoing changes. For example, add fruits and vegetables gradually over a period of weeks. Each time you shop, choose a low-fat dairy product in place of one made with whole milk. Instead of buying a loaf of white bread, try one made with 100% whole grain flour such as whole wheat or rye.

"It isn't necessary to give up all the foods you like to help protect yourself from cancer. Instead, try to increase the number of times you choose foods that may reduce your risk of cancer," McDowell said.

JoAnn Petaschnick
HealthLink Contributing Writer

MCW Health News presents up-to-date information on patient care and medical research by the physicians of the Medical College of Wisconsin.