Quoted from The Hundred Year Lie:

Broccoli is another powerful ally for the human immune system. A study by a research team at Johns Hopkins University published in a 2005 issue of Proceedings of the National Academy of Sciences uncovered strong evidence that phytochemicals in broccoli detoxify certain cancer-causing agents and also act in producing enzymes that fight pain and inflammation, making broccoli potentially more effective than Vioxx and other prescription drugs commonly issued for arthritic conditions.

Almost every major medical condition is either caused by or affected by what you eat, says Isadore Rosenfeld. “Yet very few medical doctors are knowledgeable about nutrition. As a result, they rarely give nutritional advice—even when specific foods can help curb symptoms or correct underlying problems as well as or better than prescription medications.”

Nutritionists and physicians who have taken the time to study nutrient values generally recommend these natural foods for health: Mushrooms are high in B vitamins and selenium, and studies have shown they boost immune system activity, elevate antioxidants, and lower blood pressure and insulin levels. Blueberries and spinach are both high in vitamins and antioxidants. Walnuts, Brazil nuts, and almonds are immune system boosters from the nut family. Most of the cruciferous vegetables—broccoli, cabbage, cauliflower, collard greens, turnips, kale, and radishes—have demonstrated their effectiveness against colon cancer and intestinal polyps.

When fruits and vegetables are analyzed for their antioxidant potential, a score known as oxygen radical absorbance capacity, five foods in each category stand out for their health benefits: among fruits, prunes score 5,770, raisins 2,830, blueberries 2,400, blackberries 2,036, and strawberries 1,540; among vegetables, kale scores 1,770, spinach 1,260, brussels sprouts 980, alfalfa sprouts 930, and broccoli 890.

Fitzgerald, Randall. The Hundred-Year Lie: How to Protect Yourself from the Chemicals That Are Destroying Your Health (pp. 182-183). Plume. Kindle Edition.