Anticancer Benefits of Oranges
On average, orange trees (Citrus sinensis) grow to a height of 7.5 meters, although relatively old ones may reach 15 meters. The crowns are rounded with slender branches and white fragrant flowers. Orange is thought to have originated from southeastern Asia (Indochina), southern China and northeastern India. The Spaniards are believed to have introduced sweet oranges into North and South America in the mid-1500s. Currently, the U.S.A. is the leading producer of oranges in the world. (i.236, 237)
Tangerines are actually a plant class in its own right, which is composed of oranges with loose and thin peels. Scientifically known as Citrus reticulata, fruit of mandarin trees are commonly called tangerines. Although the trees resemble sweet orange trees, they are generally thornier. The peels are either red-orange or bright orange when ripe and separate from the segments easily. (i.238)
Nutritional Value of Oranges
Oranges and tangerines are low in sodium, cholesterol, and saturated fat. On the other hand, they are rich in vitamin A and vitamin C. They also contain plenty of dietary fiber, and the peels are rich in essential oils. Other important nutrients include: (i.239-, 240)
Anticancer Benefits
Vitamin C is a known antioxidant that can protect cells from the kind of damage which can lead to cancer. Clinical studies show that adults who had high vitamin C levels had less risk of infection from ulcer-causing Helicobacter pylori, believed to be a risk factor for stomach cancer. However, researchers have determined that the vitamin C content in oranges represent only part of its cancer-fighting antioxidant power. (i.229, 237)
Fiber and phytonutrients, such as the various carotenoids that give the fruits their color, and various flavonoids, may also help protect cellular DNA and exert other anti-cancer effects: (i.53, 136, 138, 139, 237)
- A population study involving 60,000 people in China found that high intake of one flavonoid, a xanthin-type carotenoid in oranges and tangerines, was associated with substantially lower risk of lung cancer. This benefit was also found in smokers — unlike beta-carotene, a carotenoid that may increase cancer risk if taken in high amounts (alone, as a supplement) by those who smoke.
- Oranges contain the cancer-fighting antioxidant and anti-inflammatory flavonoid apigenin, which suggest can protect against cancer. For example, topical application of apigenin in animal studies inhibited UV-light damage from causing skin cancer, while multiple lab and animal experiments show it can help inhibit harmful free radicals and transformation of normal cells into malignant ones. Further research (lab, animal, and human clinical and population studies) indicates apigenin may also have potential as a natural chemotherapy agent against adrenal gland, brain, breast, cervical, colon, endometrial, leukemia, liver, lung, ovarian, prostate, stomach, and thyroid. Mechanisms of action include inhibiting tumor growth, invasion, and lung metastases to actually inducing cancer cell death.
- Hesperidin and nariutin are flavonoids in oranges that lab and animal studies show have antioxidant and anti-inflammatory properties.
- The dietary fiber in oranges can bind up toxins in the digestive tract and help protect cells there from damage that may cause colon cancer.
Animal studies suggest that flavones from the peels (tangeretin and nobiletin) can help lower dangerous cholesterol levels — potentially another anticancer benefit from eating oranges and tangerines. The fiber and natural sugars from these low-glycemic index whole fruits can help regulate blood sugar levels as well. High levels of glucose and LDL-type cholesterol in the blood and triglyceride accumulation in the liver can lead to conditions such as diabetes, heart disease, and non-alcoholic fatty liver disease (NAFLD). These chronic inflammatory conditions often contribute to increased risk of cancer. (i.155, 228, 237, 239, 240)
Adding Oranges to Your Diet
Both organic and non-organic oranges may have brown or partially green color when ripe, but these variations from a bright orange color don't necessarily detract from flavor or quality. However, avoid light-weight fruit with soft spots, bruises, or wrinkled skin. Choose organic oranges if possible to avoid pesticide residues. Heavier, smaller oranges with smooth-textured skin tend to have more juice content. Fully ripe fruits have the highest antioxidant content. (i.1, 237)
You may store your oranges either in a refrigerator or at room temperature. Whichever method you use, the oranges will last for two weeks and still retain the levels of vitamins as fresher fruit. However, tangerines decay relatively fast and are frequently harvested early and shipped with diphenyl fungistat. Although some suggest putting them in plastic bags in the refrigerator crisper drawer, horticultural experts disagree. They caution against storing in plastic bags to avoid excess moisture that can lead to the development of mold. You can also store orange juice or dried orange zest (grated orange peel) in the freezer. (i.1, 237, 238)
Preparation
If you want orange juice, you may squeeze the fruits by hand or use a juicer. Juice them when they are warm, such as at room temperature, to get more juice. Alternatively, you may simply peel and eat the fruits. Mandarin oranges can be peeled by hand with relative ease. Choose organically grown oranges if you want zest to avoid artificial coloring or pesticide residues. You can remove the zest (the orange portion of the peel) using a vegetable peeler, paring knife or zester. Take care to avoid the underneath white pith, which is bitter. (i.237)
Orange juice and zest are often included in sauces and baked desserts. Try grating some into a salad to take advantage of its potentially cholesterol-lowering benefits. Mandarin oranges are usually eaten out-of-hand although their sections may also be used in puddings, gelatins, or salads as well as on cakes. (i.237, 238)
Growing Oranges
Although both types of oranges are mostly grown commercially in warm, subtropical climates (e.g., Florida and Mexico) mandarin orange trees are more tolerant to drought and colder temperatures than C. sinensis trees. Cold damages the fruit from C. sinensis easily, but if protected mature trees can survive up to ten hours of below-freezing temperatures. (i.236, 238)
Orange trees can be grown in well-drained soil in warm climates. Plants should be chosen that are suitable for the soil in the area (such as sandy in Florida and loamy in California). (i.236)