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An apple a day — plus some spinach, a handful of nuts and a helping of flaxseed — may help keep cancer away.

Many foods already associated with a healthy diet could help prevent some types of cancer, says Brooke Schoonenberg, a Woman’s Hospital dietitian who teaches a class called “Cancer Fighting Foods.”

“These foods, of course they have anti-cancer benefits,” Schoonenberg says, “but they’re also heart healthy and they are great for weight management and preventing diabetes. You can’t go wrong with fruits and vegetables.”

Based on research from the American Institute for Cancer Research, Schoonenberg’s list includes high-fiber foods that fight colon and rectal cancers and healthy fruits and vegetables that prevent weight gain. Obesity has been linked to several types of cancer, including esophageal, pancreatic and post-menopausal breast cancer, in studies by the National Cancer Institute.

Many of the foods on the list also contain antioxidants — certain molecules that fight free radicals, which are compounds that can hurt cells. When damaged cells reproduce, they can cause cancer, Schoonenberg says.

“Your body can produce some antioxidants itself, but in this day and age, we don’t produce enough to fight all the environmental toxins,” she says. “You have to get an outside source of antioxidants, and that is where your food comes in.”

However, following a strict diet cannot prevent all cancers.

“Unfortunately, even the healthiest of humans that exercise every day and eat right, that doesn’t mean you’re not going to get cancer,” Schoonenberg says. “This is really just doing everything in your control to prevent it.”

Flaxseed

A great source of dietary fiber, flaxseed can lower the risk of colorectal cancer. Flaxseed also contains omega 3 fatty acids, which doctors recommend for several health-related issues, from asthma to depression.

The seeds can be eaten whole in oatmeal or cooked in meatloaf. Schoonenberg advises patients to grind the seeds, which can be used as an egg replacement in recipes.

“If you grind it up, it has more of those Omega 3 fatty acids available,” she says. “If you keep it whole, it acts more like a fiber, an insoluble fiber. If you grind it up, then you’re able to absorb more of those fatty acids.”

Apples

An apple a day may not actually keep the doctor away, but one does provide 10 percent of your dietary fiber and vitamin C.

Pectin in apples also protects colon cells, according to the AICR, and the fruit contains antioxidants such as quercetin and triterpenoids.

It might be most helpful to eat the whole thing. According to the AICR, a third of an apple’s antioxidants are found in the peel.

Spinach

All green leafy vegetables contain fiber, which can protect against colorectal cancers, and carotenoids, pigments that some researchers have found fight the growth of some types of cancer cells.

Schoonenberg recommends spinach as the most versatile leafy green.

“You can do a salad,” she says. “That’s the one vegetable I tell people to blend into their smoothies, too. It turns it toxic green, but you can’t taste it. For people who are not veggie lovers, that’s a great way to sneak them in, as long as you don’t drink it in a clear cup.”

Walnuts

These popular nuts have several antioxidant polyphenols, including some that lower blood cholesterol.

Nuts are also associated with brain health, making them a great all-around snack, Schoonenberg says.

Walnuts are great to eat cooked or raw.

“The amount of toasting they are going to go through isn’t the equivalent of taking a raw piece of broccoli and boiling it to death, where you’re exposed to that kind of extreme heat,” she says.

Tomatoes

This versatile fruit contains lycopene, a phytochemical that has received a lot of attention for its cancer-fighting properties.

While you get lycopene from all tomatoes, a good marinara sauce might pack more of the antioxidant power.

“The lycopene is enhanced when you cook it,” Schoonenberg says. “That doesn’t mean that it’s not good for you if it’s not cooked. It still is.”