You can believe in the power of superfoods — to help you live longer, lose weight, manage type 2 diabetes and stave off cardiovascular disease — and still question whether any green or grain is super enough to reduce your risk for cancer. After all, the science on the cancer-preventing powers of specific foods is ongoing.
But this much is clear: Regularly filling your plate with foods that protect your immune system, support a healthy weight, reduce inflammation and promote gut health can help reduce your risk for cancer, according to the American Cancer Society. Further, not doing so comes at a price. One study published in 2019 in JNCI Cancer Spectrum suggests that a poor diet — meaning one that skimps on fruits, vegetables, whole grains and dairy and goes heavy on red meat and processed foods — may account for more than 5 percent of new invasive cancers in adults in the U.S.
“There are not specific foods that have been shown to prevent cancer, but there are eating habits over a long period of time that have been shown to help reduce the risk of developing cancer,” says Stacy Kennedy, a registered dietitian and board certified specialist in oncology nutrition in Wellesley, Massachusetts.
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She compares the impact of healthy eating habits to regular exercise. “We know that physical activity can help support a healthy weight and help reduce the risk for cancer, but we don’t generally call out one specific form of exercise as being advantageous over another. There are a lot of forms of exercise that would be helpful because they all fall under that umbrella of physical activity.” Same goes with the superfoods that land under the umbrella of healthy eating habits. “It’s that healthy pattern that helps [reduce the risk for cancer] more than specific foods,” Kennedy says.
With that in mind, here are seven standout superfoods that should be a part of any cancer-preventing eating plan.
1. Pulses (beans, peas, lentils)
You know a food has true superpowers when it appears on virtually every nutritionist’s must-eat list. In a report published in 2020 in The Journal of Nutrition, the World Cancer Research Fund and the American Institute for Cancer Research (AICR) recommend following a diet that provides at least 30 grams of fiber per day; five or more servings a day of plant foods; and whole grains, nonstarchy vegetables, fruit and pulses at most meals.
The beans, peas, chickpeas and lentils — collectively known as pulses, or legumes — check all those boxes. “This food group holds its status as a superfood for more than just one reason,” says Kristin Kirkpatrick, a registered dietitian at the Cleveland Clinic. “Legumes are low in fat and high in protein. They’re also high in insoluble fiber, which aids in digestion and an overall healthy gut.” Research also suggests that eating plant-based foods rich in fiber can reduce the risk of colorectal cancer.
Broccoli and its cruciferous cousins — cauliflower, cabbage, brussels sprouts, kale and collard greens — have long been associated with a reduced risk of cancer thanks to a molecule in each of these veggies that inactivates a gene that plays a role in a variety of cancers, according to the AICR.
Broccoli — the most commonly consumed cruciferous vegetable in the U.S. — tends to get star billing if only because it’s the richest source of that cancer-thwarting molecule, sulforaphane. Research from a Harvard team also suggests that broccoli and brussels sprouts have tumor-suppressing capabilities. And let’s not overlook the fact that this family of vegetables is packed with other health-boosting nutrients.
When researchers at Pennsylvania State University reviewed 17 cancer studies published between 1966 and 2020, they found that people who included mushrooms in their daily diets had a lower risk of cancer. The secret ingredient? Ergothioneine, a unique and potent antioxidant that protects cells. Turns out mushrooms — especially shiitake, oyster, maitake and king oyster mushrooms — have more ergothioneine than any other food.
The study, published in 2021 in Advances in Nutrition, analyzed the data of more than 19,000 cancer patients and found that those who ate about a quarter-cup of mushrooms every day had a 45 percent lower risk of cancer than those who didn’t eat mushrooms. “Mushrooms have properties that may help some of our immune cells do their job in an optimal way,” Kennedy explains. “Our immune system is what helps protect us against cancer.”
Walnuts have long interested cancer researchers, and it’s easy to see why. Animal studies suggest that walnuts slow the growth of breast, prostate, colon and renal cancers, thanks to a number of compounds that are believed to ward off the disease.
But that’s not to say walnuts are the only nuts that play a role in a cancer-preventing eating plan. A review of nine studies found that people who ate an ounce of nuts daily — that’s around 18 walnut halves, 15 pecan halves or 24 almonds — have a 15 percent lower overall cancer risk than those who didn’t eat nuts, according to AICR research.
“All nuts have fiber, protein and healthy fat,” Kennedy notes. But each one offers additional nutrients, so there are benefits to mixing things up. For instance, “almonds have vitamin E, walnuts have omega-3s, pistachios have calcium, Brazil nuts have selenium, which is an important antioxidant. You could go on and on.” Important to note, however: Nuts are high in calories, so keep an eye on portion sizes.
That humble bowl of steel-cut oatmeal may help bolster protection against cancer, including colorectal cancer, studies show. Whole grains like oats are loaded with fiber, antioxidants and phytoestrogens (plant-based compounds that have a slew of health benefits, including a lowered risk of osteoporosis, heart disease and breast cancer), all of which help protect against cancer.
Not a fan of oatmeal? Bulgur, brown rice, barley, corn, quinoa and whole wheat couscous have the same cancer-fighting properties.
Berries earn their cancer-fighting bona fides in a couple of ways. For starters, all berries — strawberries, blueberries, blackberries, raspberries — are packed with cancer-fighting plant compounds known as phytochemicals. When you eat them, these phytochemicals interact with one another, other nutrients and your gut bacteria to help fend off chronic diseases like cancer, says Jill Weisenberger, a Virginia-based registered dietitian nutritionist and author of The Overworked Person’s Guide to Better Nutrition.
They’re also low in calories, so they play an equally big role in maintaining a healthy weight. Excess body weight is thought to be responsible for about 7 percent of all cancer deaths, according to the American Cancer Society. “Eat a variety of berries because each one has a different array of protective compounds,” Weisenberger suggests.
There’s no wrong way to eat any fruit or vegetable, but tomatoes kick into overachiever mode when cooked. Why? The amount of lycopene — the cancer-fighting carotenoid responsible for making tomatoes red — is often much higher in processed foods like tomato juice and pizza and pasta sauce than in fresh foods.
“Lycopene is a fat-soluble nutrient, and so cooking helps to release more of it,” Kennedy explains. “When consuming cooked tomatoes, have a healthy fat with it — whether it’s avocado, nuts, olive oil — to boost absorption by the body.”
Kimberly Goad is a New York–based journalist who has covered health for some of the nation’s top consumer publications. Her work has appeared in Women’s Health, Men’s Health and Reader’s Digest.