- Eating more vegetables every day can help reduce your risk of cancer.
- Vegetables’ fiber, antioxidants, and bioactive compounds can help protect your cells.
- Mix up your vegetables – Variety offers the most comprehensive health and cancer-fighting benefits.
There is no one-size-fits-all way to prevent cancer, but what you eat appears to play a role in risk. Decades of studies suggest that about 30% of various cancers could be prevented through a healthy diet. And eating more vegetables seems to be at the top of the list.
“If one food group were to be described as protective, it would be vegetables.” Cynthia Thomson, PhD, RDa professor at the University of Arizona who studies the connection between diet and cancer risk, pointing to high levels of bioactive compounds, or naturally occurring chemicals, that can promote health.
But how many servings of vegetables should you aim for? Here’s what science says, why they’re important, and how they can enrich your day.
The Science: How Many Servings Make a Difference?
There is no exact number of vegetable servings that will surely reduce your risk of cancer, but it’s best to aim for a specific amount of vegetable servings at least three servings a day, says Thomson.
Research backs up that number, says Sarah Pflugradt, Ph.D., RDN, CSCS, pointing to a 2021 meta-analysis of more than two dozen cohort studies. That research found that eating five servings of fruits and vegetables daily — divided into two servings of fruit and three servings of vegetables — is associated with a lower risk of cancer and other causes to die.
These results are consistent with the 2020-2025 Dietary Guidelines for Americans and National Cancer Institute recommendations:
To put the portions in perspective:
- 1 cup raw, cooked, frozen or canned vegetables = 1 serving
- 2 cups raw leafy greens = 1 serving
Why vegetables help reduce the risk of cancer
There are three main reasons why vegetables can help reduce the risk of cancer.
They are rich in bioactive compounds
Vegetables contain hundreds of bioactive compounds, which are naturally occurring chemicals with anti-cancer properties, says Thomson. An example is glucosinolates.
“Cruciferous vegetables such as Brussels sprouts, broccoli, cauliflower and kale contain nutrients called glucosinolates, which have been shown to protect against certain cancers such as prostate, breast, liver and colon cancer,” says Pflugradt.
More specifically, these compounds can protect your cells from damage, reduce inflammation, help inactivate cancer-causing compounds, and even inhibit tumor growth.
Pflugradt gives further examples of bioactive compounds that could be useful for cancer prevention:
- Vitamin C and beta-carotene: is found in many orange and red vegetables such as peppers, carrots and sweet potatoes.
- Organic sulfur compounds: occurs in alliums, for example in onions, garlic, leeks and shallots.
They support a healthy weight
Vegetables are naturally low in calories and high in fiber, which helps you feel fuller for longer. Since obesity and overweight are linked to a higher risk of cancer, vegetables can be a helpful part of weight management, says Thomson.
“This is one reason why supplements are not a one-to-one replacement for vegetables,” says Lauren Manaker, MS, RDN, LD, CLEC. “Of course, you can get your vitamin C needs with a supplement, but you would be missing out on the fiber and many other beneficial compounds that work together in whole vegetables to protect your health. It’s the synergy of these nutrients that makes vegetables so powerful.”
They often come with other healthy options
“People who choose a diet high in vegetables also generally eat other healthy options,” adds Thomson. This is not a direct benefit of eating vegetables, but it is important to remember that eating plenty of vegetables is just one component of a healthy lifestyle that helps prevent cancer.
This way you get more portions every day
Variety is key. “Not all vegetables have the same nutrients,” says Plfugradt. So make sure you have a colorful mix.
Try these tips from our experts:
- Shop with your vegetarian goal in mind: “Every time you go to the grocery store, start by shopping for fruits and vegetables and buy enough for 15 to 20 servings per week,” says Thomson. Choose a rainbow of colors and try a new vegetable every week.
- Prepare vegetables easily: “Wash, chop, and refrigerate so they’re ready to snack on or add to meals,” says Manaker.
- Add vegetables to hot dishes: Stir vegetables like kale or spinach into soups, pastas, or grain bowls, says Pflugradt.
- Blend vegetables into smoothies. Frozen grated cauliflower adds creaminess and adds an extra helping of vegetables without changing the flavor, says Manaker. Leafy greens are another option.
- Stock your freezer: Have frozen vegetables like peas, corn, and green beans on hand if you’re pressed for time, recommends Pflugradt.
- Use prepackaged salads: “Pre-washed greens are a lifesaver on busy days,” says Manaker. “Add some protein and a simple dressing and you have a quick, vegetarian meal.”
- Make it a challenge: Get competitive with a friend, colleague or family member, suggests Thomson. You can decide the exact rules yourself – maybe see who can reach their vegetarian goal the most in a month or who can eat the largest variety of vegetables in a week.
“I really like to challenge people to eat more vegetables for three to four weeks and see if they feel so much better,” says Thomson. “At the very least, they’re happy to have regular bowel movements and more energy overall.”
Recipes to try
25 Vegetarian Side Dishes You’ll Want to Make Forever
Our expert opinion
While many factors influence cancer risk, nutrient-dense foods such as fruits, vegetables, whole grains and nuts have been shown to help reduce cancer risk. But if you had to prioritize just one of them, it would have to be vegetables, says Thomson.
Aim to eat at least three servings a day – ideally more – and mix up the types you eat to get the most benefit. And remember, vegetables are just one part of a healthy lifestyle, which includes staying active, getting enough sleep and limiting alcohol consumption.