By Clayton Simmons, published on April 2, 2009 - last reviewed on December 31, 2012
How can you make sure you're eating a balanced diet? Forget frantically calculating the relative benefits of bananas, tomatoes, spinach, and kale. Just think in technicolor. The compounds that give fruits and vegetables their color also have unique nutritional properties, so by eating a wide array of colors, you can maximize these benefits. A colorful diet protects your body against a multitude of ailments: cancer, heart disease, arthritis, and vision loss, among others. Here's a handy color-coded food guide:
Fruits with a red hue, such as tomatoes, guava, and papaya, contain lycopene, a reddish pigment and nutrient. Large studies indicate that this substance protects against a variety of cancers, including that of the prostate, stomach, and lung. As an antioxidant, lycopene protects cell structures and DNA against the nefarious effects of free radicals—small particles that damage healthy cells and allow tumor cells to develop. Indeed, one study in Nutrition and Cancer showed that lycopene was better than two other antioxidants—alpha and beta carotene—at stopping uterine, breast, and lung cancer cells from developing in test tubes.
Carrots, mangoes, apricots, pumpkins, and sweet potatoes, are brimming with cryptoxanthin and beta-carotene—two substances that reduce the risk for a variety of mental and physical ailments. For example, cryptoxanthin protects against arthritis and cancer, while beta-carotene keeps the mind sharp. In a 2005 study from the Archives of Internal Medicine, cryptoxanthin protected individuals from developing rheumatoid arthritis, even as other antioxidants did not; other studies suggest it reduces risk for lung cancer. Beta-carotene, for its part, kept cognition and memory from declining in a group of doctors who took part in an 18-year study published in the Archives of Internal Medicine.
Spinach, salad, and other leafy vegetables protect the eyes and the heart, among other important body parts. Lutein and zeaxanthin, two nutrients found in these foods, keep us from going blind by reducing the risk of cataracts in old age. Even better are the effects that greens have on the heart. For every daily serving you eat, you reduce your risk for heart disease by 11 percent, found a study published in the Journal of the National Cancer Institute. Leafy greens also contain vitamins A and C, which help keep the body from creating oxidized cholesterol—the stuff that sticks in the arteries and clogs them.
The dark red-purple hues of berries, beets, and purple cabbages are derived from anthocyanins. These prevent tumor growth and may have anti-inflammatory properties that reduce pain from arthritis and protect against heart disease. Even in individuals undergoing cancer treatment, berries may be helpful—there is some evidence they aid in chemotherapy by diminishing cancer cells' ability to survive the onslaught of poison contained in anti-cancer drugs, noted Navindra Seeram, MD, in the Journal of Agricultural and Food Chemistry.
Although not technically fruits or vegetables, beans can play an important role in maintaining a healthy diet. Lentils, black beans, and chickpeas are an excellent source of folate, a B vitamin that helps to prevent damage to arteries by reducing homocysteine. Homocysteine, an amino acid, can cause harm to arteries and allow clots to form more easily, which in turn ups the risk for heart disease, heart attack, and stroke. By reducing blood levels of homocysteine, folate keeps blood vessels pristine.