Antioxidants protect cells against free radicals, which are unstable substances found in the environment. According to the National Cancer Institute, damage from free radicals can lead to cancer. There is laboratory evidence that antioxidants may slow and even prevent cancer. Examples of antioxidants found in food sources include beta-carotene, lycopene and vitamins A, C and E. These are ten top sources of antioxidants.

Broccoli

Broccoli belongs to the cruciferous family of vegetables which also includes cauliflower, cabbage and Brussels sprouts. It is also a source of beta-carotene. Cruciferous vegetables contain the potent antioxidant, indole-3- carbinol, which breaks down estrogen. This reduces the risk of breast, ovarian and cervical cancers.

Tomatoes

Tomatoes are rich in lycopene, which is a potent antioxidant that is twice as powerful as beta-carotene. Tomatoes reduce the risk of prostate, lung, colon and breast cancer. They contain glutathione, which is an antioxidant that boosts the immune system. Two tips on how to get the maximum health benefits from tomatoes- cook tomatoes and dress with olive oil. Heat releases more desirable antioxidants and oil improves absorption because lycopene is fat-soluble.

Berries

Beneficial berries contain two cancer fighting agents. Blueberries, raspberries and blackberries are rich in proanthocyanidin, which is an antioxidant that protects against cancer and heart disease. Strawberries, raspberries and blackberries contain ellagic acid which is a plant compound that fights carcinogens.

Garlic

Some studies show that an increase intake of garlic causes a reduced risk of developing gastrointestinal cancers, such as stomach, colon, pancreatic and esophageal cancers. Garlic belongs to the Allium class of plants contains flavonoids and selenium which have potential health benefits.

Carrots

Carrots contain beta-carotene which is also found in other yellow- orange vegetables such as sweet potatoes. Research from the United Kingdom found that carrots contain the anti-cancer compound, falcarinol. It is believed that cooking the carrots whole before cutting provide the highest levels of falcarinol. The beta-carotene in carrots protects against lung, bladder, breast, esophageal and stomach cancers.

Tea

Tea contains catechins which are antioxidants that selectively inhibit specific enzyme activities that lead to cancer. Green tea is less processed than black tea and contains higher levels of antioxidants than black tea. Steeping either green or black tea for about five minutes releases 80 percent of its catechins. Instant iced tea mixes contain negligible amounts of this antioxidant.

Red Wine

Red wine is a rich source of catechins and resveratrol which are thought to have antioxidant properties. These two polyphenols are found in the skin and seeds of grapes. Red wine contains more polyphenols than white wine because in the process of making white wine, the skin is removed after the grapes are crushed.

Kale

Kale is a dark green leafy vegetable that is a rich source of vitamins A, B-complex, C, E and K and antioxidants. Studies show that eating kale lowers the risk for lung, colon, colorectal, ovarian and prostate cancers.

Whole Grains

Whole grains offer protection against gastrointestinal cancers , especially gastric and colon cancer, and hormone-dependent cancers, such as breast and prostate cancer. Whole grains are an excellent source of dietary fiber, antioxidants and a significant source of phytoestrogens, which have hormonal effects related to cancer prevention.

Flaxseed

Flaxseed is a good source of omega-3-fatty acids which help prevent colon cancer. It has a high lignan content. Lignan is an antioxidant that reduces the proliferation of cancerous cells. Preliminary research has shown a decrease in tumor size among breast cancer patients who followed a controlled diet with the addition of supplemental flax lignan capsules.