Here are eight foods (or food groups) with the strongest scientific evidence:
1. Cruciferous Vegetables
Examples:
- Broccoli
- Cauliflower
- Brussels sprouts
- Cabbage
- Kale
- Bok choy
Why they’re beneficial:
- Rich in glucosinolates, which break down into compounds such as sulforaphane and indole-3-carbinol.
- These compounds have shown anti-cancer effects in laboratory studies by:
- Helping remove carcinogens.
- Reducing inflammation.
- Supporting DNA repair.
- Encouraging damaged cells to die (apoptosis).
Evidence:
Population studies suggest eating more cruciferous vegetables is associated with a lower risk of colorectal, lung, and some other cancers, though the evidence is stronger for prevention than for treatment.
How much:
Aim for 3–5 servings per week.
2. Berries
Examples:
- Blueberries
- Strawberries
- Blackberries
- Raspberries
Why they’re beneficial:
Berries contain:
- Anthocyanins
- Vitamin C
- Ellagic acid
- Fiber
These nutrients:
- Act as antioxidants.
- Help reduce inflammation.
- May protect DNA from damage.
Evidence:
Human studies suggest diets rich in berries may reduce oxidative stress and inflammation, although they are not a treatment for cancer.
Serving:
About 1 cup several times per week.
3. Tomatoes
Tomatoes are especially rich in:
- Lycopene
- Vitamin C
- Potassium
Potential benefits:
Lycopene has been studied extensively for prostate cancer prevention.
Cooking tomatoes (such as tomato sauce) actually increases lycopene absorption.
Best sources:
- Tomato sauce
- Cooked tomatoes
- Tomato paste
4. Garlic and Onions
These belong to the allium family.
They contain:
- Allicin
- Organosulfur compounds
Research suggests these compounds may:
- Reduce inflammation.
- Help detoxify harmful substances.
- Slow growth of abnormal cells in laboratory studies.
Some studies associate higher intake with lower risks of stomach and colorectal cancers.
5. Beans and Lentils
Examples:
- Black beans
- Kidney beans
- Chickpeas
- Lentils
Benefits:
- High in fiber
- Rich in folate
- Plant protein
- Polyphenols
Fiber supports healthy gut bacteria and is associated with a lower risk of colorectal cancer.
Aim for:
3 or more servings each week.
6. Whole Grains
Examples:
- Oats
- Brown rice
- Whole wheat
- Barley
- Quinoa
Whole grains provide:
- Fiber
- Selenium
- B vitamins
Large studies have found that people who eat more whole grains tend to have a lower risk of colorectal cancer.
7. Fatty Fish
Examples:
- Salmon
- Sardines
- Mackerel
- Trout
Rich in:
- Omega-3 fatty acids
- Vitamin D
- High-quality protein
Omega-3 fats may:
- Reduce inflammation.
- Support immune function.
Some evidence suggests benefits for overall health, though results for cancer prevention are mixed.
Aim for:
2 servings weekly.
8. Green Tea
Green tea contains:
- EGCG (epigallocatechin gallate)
- Catechins
Laboratory research suggests these compounds may:
- Reduce oxidative stress.
- Influence cell growth.
- Help protect cells from damage.
Human studies have shown mixed results, but drinking unsweetened green tea can be part of a healthy diet.
Foods Associated with a Higher Cancer Risk
Evidence is stronger for limiting certain foods than for emphasizing any single “anti-cancer” food. Consider reducing:
- Processed meats (bacon, sausage, hot dogs, deli meats)
- Large amounts of red meat
- Sugar-sweetened beverages
- Highly processed foods
- Alcohol (even moderate intake increases the risk of several cancers)
- Foods high in salt, especially heavily salted or preserved foods
Overall Eating Pattern Matters Most
Research from organizations such as the American Cancer Society and the World Cancer Research Fund suggests that overall dietary patterns are more important than any single food. A cancer-supportive eating pattern includes:
- Plenty of vegetables and fruits
- Whole grains
- Beans and lentils
- Nuts and seeds
- Fish in moderation
- Healthy fats like olive oil
- Limiting processed meats, alcohol, and ultra-processed foods
- Maintaining a healthy body weight and staying physically active
No food can prevent or cure cancer by itself, but a balanced diet combined with other healthy lifestyle habits can contribute to lowering the risk of several cancers and support overall health. If someone is undergoing cancer treatment, it’s important to discuss dietary changes with their oncology team or a registered dietitian, since nutritional needs can vary depending on the type of cancer and treatment.