Foods that help prevent cancer are all around us, but many people are leaving the benefits of an anti-cancer diet on the table, nutritionists say.
No single food can protect against cancer, but eating more foods that fight it will help reduce the risk of developing the disease, the American Institute for Cancer Research notes.
Diet absolutely plays a role in a cancer preventive lifestyle, says Tracy Crane, Ph.D., director of lifestyle medicine and digital health for survivorship at the Sylvester Comprehensive Cancer Center — part of the University of Miami.
“We know cancer generally takes a long time to develop, so what we eat every day — the choices we make every day — have this compounding effect on our overall cancer risk,” Crane, who is also a registered dietitian nutritionist, tells TODAY.com.
But many Americans aren’t eating enough of foods with cancer-preventive compounds, which are mostly found in a plant-based diet, she adds.
“Unfortunately, the typical American is not doing well,” Maya Vadiveloo, Ph.D., a registered dietitian and an associate professor of nutrition at the University of Rhode Island, tells TODAY.com.
“We tend to exceed intake of refined grains, added sugars, foods that are high in saturated fat, too much salt.”
How is cancer related to a diet?
A healthy diet can reduce cancer risk in several ways:
Reduced inflammation: Inflammation can increase the risk of cancer, but a healthier diet can reduce inflammation in the body, Crane notes.
Fiber benefits: Fiber can reduce the circulating levels of estrogen in the body and is linked to lower breast cancer risk, studies have found.
Fiber also increases the bulk of stool, reducing transit time through the bowels, so any carcinogenic material going through your gut will be exposed to the lining of your intestinal tract for less time — one reason fiber can reduce colon cancer risk, Vadiveloo says.
Protection from antioxidants and phytochemicals: Certain foods contain antioxidants, which prevent damage to cells, she adds. Plant-based foods also contain phytochemicals — compounds that aren’t vitamins or minerals, but also seem to have benefits for the body, Vadiveloo says.
Many phytochemicals act as antioxidants, and some can increase cancer cells’ “tendency to self-destruct,” according to the American Institute for Cancer Research. The benefits don’t seem to be there when the compounds are extracted and put into pill form.
“We don’t fully understand how they’re working together with one another to provide the benefit,” Crane says. “We just know when you eat the whole food, you’re getting it all together and that’s part of the magic that happens in the cancer prevention space.”
Avoiding obesity: A diet full of fruits, vegetables and fiber can also help people feel full and maintain a healthy weight, avoiding obesity-related cancers, Vadiveloo says.
What are the top cancer-fighting foods?
The overall goal is to eat a plant-based diet that’s rich in non-starchy fruits and vegetables, whole grains, nuts, seeds and legumes, both experts say. You don’t need to be a vegetarian, but simply aim to eat more plant-based foods.
Deep color signals the presence of antioxidants and phytochemicals, so go for intensely red, blue, green and orange fruits and vegetables, and eat a rainbow of colors to get the biggest variety of nutrients.
Good choices include:
Lycopene is a powerful antioxidant that gives tomatoes their red color. There’s evidence it’s protective against prostate cancer, both experts say. It’s particularly well absorbed when it’s eaten with a fat — such as cooked tomato sauce made with olive oil, Vadiveloo notes.
It’s one of the cruciferous vegetables, which also include cauliflower, cabbage, kale, bok choy, arugula, Brussels sprouts, collards, watercress and radishes.
“They really pack quite a punch,” Crane says. “Within the cruciferous vegetables is this compound called isothiocyanates, which we know is quite cancer protective.”
Cruciferous vegetables also are rich in fiber and low in calories, the Academy of Nutrition and Dietetics notes.
Orange vegetables, like carrots, butternut squash and sweet potatoes, and orange fruits, like cantaloupe, apricots and mangos, contain carotenoids such as beta carotene — pigments that are considered antioxidants.
Tea and coffee
A number of studies show people who have higher levels of consumption of tea and coffee have reduced risk of cancer, Crane says.
Both drinks are rich in antioxidants, Vadiveloo adds.
But it’s important to remember that adding lots of sugar, cream and syrups to coffee and tea can reverse their health effects, both experts caution.
Flaxseeds play a role in fighting inflammation and contain up to 800 times more lignan — a phytochemical that has antioxidant, anti-tumor, anti-inflammatory and antiviral properties — than other plant foods, as TODAY.com previously reported.
They also contain lots of fiber and omega-3 fats, which may suppress the growth, size and expansion of cancer cells.
“Increasing your intake of these richly colored spices may increase certain anti-cancer properties of your foods,” Vadiveloo says.
There’s no evidence to support that spices taken in supplement form have the same effect.
It contains beta-carotene, fiber and potential cancer-protective phytochemicals that make it a “nutritional powerhouse,” the American Institute for Cancer Research notes.
Look for other dark leafy greens such as kale, mustard greens and collard greens to add to your diet.
It’s a whole grain and a plant-based protein, both of which reduce the risk of cancer, Crane says.
Other whole grains include brown rice, farro, bulgur and sorghum.
What foods increase the risk of cancer?
They include lunch meat, bacon, hot dogs and sausage. “If I were to pick one food (to avoid), it would be processed meat,” Vadiveloo says.
The World Health Organization has classified processed meat as carcinogenic to humans.
Drinking alcohol raises the risk of getting cancer of the breast, liver, colon, and mouth and throat, according to the Centers for Disease Control and Prevention.
Too much added sugar
Sugar itself doesn’t necessarily lead to cancer, but too much sugar in the diet leads to weight gain and obesity, which raises cancer risk, the University of Texas MD Anderson Cancer Center notes.
“In particular, sugar-sweetened beverages are a key culprit to the rising obesity rates,” Crane says.
Studies have found that men who ate large amounts of ultra-processed foods — such as potato chips, candy, store-bought cookies and soft drinks — had a 29% greater risk of colorectal cancer than men who consumed smaller amounts.
Meats cooked at high temperatures
Grilling and pan-frying beef, pork, fish or poultry can prompt potentially cancer-causing chemicals to form, according to the National Cancer Institute.