A number of scientific studies over the years show that certain vegetables, fruits and other healthy products can protect you against cancer. But did you know you can boost your defenses even more? Evidence is mounting that combining specific foods can provide powerful protection through a process called synergy, in which nutrients in foods, such as vitamins, minerals, and phytochemicals, combine to work together better than they do individually, board-certified family practitioner Dr. David Brownstein tells Newsmax Health.

 Take advantage of the cancer-fighting potential of the following combinations:

• Tomatoes and broccoli. Tomatoes are packed with lycopene, vitamin C, and vitamin A, and broccoli contains the phytochemicals beta-carotene, isothiocyanates, and indoles, all of which are cancer-fighters by themselves, but pack a powerful blow to prostate cancer when combined. An animal study at the University of Illinois found that the tomato/broccoli combination shrank prostate tumors more than either food alone. The only treatment that was as effective as the food combo was castration. 

• Tea and lemon. Tea is high in antioxidant polyphenols, including catechins and flavonoids. According to the USDA, a single cup of green tea has the same amount of flavonoids as almost five glasses of red wine or nine apples. Catechins, a particularly potent cancer-fighter, break down quickly in the intestinal tract, and usually only about 20 percent is available for absorption after digestion. However, scientists at Purdue University found that adding lemon to green tea allowed 80 percent of the catechins to remain after digestion.

• Kale and lemon. Citrus fruits provide generous amounts of vitamin C, and dark, green leafy vegetables are rich in iron.   "The vitamin C from both foods make the plant-based iron more absorbable," says Dr. Brownstein.

• Beef and rosemary. Grilling protein-rich foods like red meat forms heterocyclic amines (HCAs) and polycyclic aromatic hydrocarbons (PAHs), carcinogens that cause changes in DNA linked to cancer. A study at the University of Minnesota found that well-done meats, regardless of cooking style, increased the risk of pancreatic cancer by 60 percent, as well as raised the risk of prostate, breast, liver, lung, and breast cancers. Rosemary contains the antioxidants rosmarinic acid, carnosol, and carnosic acid, and a study found that marinating grilled foods in rosemary extract lowered the amount of cancer-causing chemicals when grilled. A study published in The Journal of Food Science found that high concentrations of rosemary reduced cancer-causing chemicals by more than 90 percent.

• Turmeric and black pepper. Many studies show that turmeric, a staple in Indian dishes, has anticancer and anti-inflammatory properties due to its active ingredient curcumin. Curcumin has been shown to thwart stomach, liver, lung, and breast cancer. Peperine, black pepper's spicy component may play a key role in deterring cancer.

• Tomatoes and avocado. Tomatoes are loaded with lycopene, an antioxidant that's a type of carotenoid. One study found that eating more than 10 servings of lycopene a week reduced the total risk of prostate cancer by 35 percent and the risk of aggressive prostate cancer by 53 percent. "The fat from avocados increases the bioavailability of the carotenoids in tomatoes," says Dr. Brownstein.

• Strawberries and oatmeal. All whole grains contain antioxidants, but oatmeal has higher levels than most other grains, and the phytochemicals it contains fight inflammation, a condition that's been linked to cancer. Strawberries have high amounts of ellagic acid, which studies have shown deactivate specific carcinogens and help prevent cancers of the lung, breast, bladder, esophagus, and skin.