Do Walnuts Help Fight Cancer?


Jennifer Larson

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hands holding large scoop of walnuts

Like pecans, Brazil nuts, and cashews, walnuts belong to the tree nut family. They’re a tasty source of health benefits, and it’s easy to incorporate a serving of walnuts into your diet—one serving, or about an ounce, is equal to about 14 walnut halves. Could a daily afternoon snack of walnuts or a sprinkling of walnut halves on top your morning bowl of oatmeal or yogurt help reduce your risk of developing cancer?

Perhaps. It’s worth considering the health benefits of walnuts and how they might contribute to an overall healthier lifestyle and a lower risk of cancer.

A Great Source of Omega-3 Fatty Acids

Talk to any registered dietitian, and they’re likely to extoll the virtues of foods high in omega-3 fatty acids. Omega-3 fatty acids are one category of the essential fatty acids that the body and brain need to be healthy. But your body can’t make these fatty acids itself, so you have to get them from foods such as salmon, halibut, tuna, and, yes, walnuts.

In fact, making an effort to eat more foods high in omega-3 fatty acids like walnuts can also help you keep a better ratio of omega-3 fatty acids to omega-6 fatty acids. Omega-6 fatty acids are another essential fatty acid that you must get from food (like vegetable oil) because your body doesn’t produce it, either. However, omega-6 fatty acids tend to increase inflammation in the body, so inflammation-reducing omega-3s can keep that in check and maintain a healthy balance. Eating a diet rich in omega-3 fatty acids also seems to reduce the risk of developing breast and prostate cancers. In fact, some research suggests that diets containing walnuts may affect the way some genes regulate cell growth, which may lead to a slower growth rate of certain tumors.

There are other benefits of eating walnuts and foods containing omega-3 fatty acids. A healthier balance of these fatty acids also seems to reduce your risk of developing heart disease.

A Source of Ellagic Acid

But walnuts are more than just a source of omega-3 fatty acids. A compound known as ellagic acid is found in walnuts and pecans, as well as in fruits like strawberries, raspberries and cranberries. Ellagic acid is a phytochemical. Phytochemicals, which given plants their colors and flavors, are known for reducing inflammation and blocking oxidative damage to cells that can lead to cancer.

When you eat foods containing ellagic acid, some of the bacteria in your digestive tract zeroes in on the acid and converts it into a substance called urolithin. Some research suggests that one particular type of urolithin, known as urolithin A, may have cancer-inhibiting effects.

More Research Needed

At this point, you want to put walnuts in the category of “won’t hurt/might help.” Many researchers note it’s possible that walnuts are helpful in the fight against cancer. In fact, a 2016 study published in the journal Cancer Prevention Research suggested that eating walnuts may help you ward off colon cancer.

But overall, the evidence is still limited enough that no one has drawn a definitive conclusion. Some of the most promising research has only been conducted with mice, and scientists hope to conduct future research using actual people before they can make a recommendation for eating walnuts as a cancer-protection measure.

However, walnuts are still good for you, regardless of whether or not they’re specifically fighting off cancer. And if you enjoy the flavor, consider adding them to a salad or yogurt for a little extra healthy crunch.