Once upon a time in the Victorian era, citrus fruits were rare and expensive, a delicacy to be enjoyed only on special occasions. Earlier still, the presence of oranges or lemons literally could make the difference between life and death for sailors suffering from scurvy on long voyages. Today, we take oranges, mandarins, grapefruits, lemons, and limes for granted, drinking their juice or eating their flesh as a snack, without batting an eye. Now, as then, oranges and other citrus are delicious snacks that include powerful nutrients and antioxidants and provide multiple health benefits, including reducing the risk of some cancers, stroke, and cardiovascular disease.
Citrus fruits contain fiber, folate, potassium, calcium, vitamins A & C, and many other nutrients, including carotenoids and flavonoids. A joint 2003 report by the World Health Organization and the U.N. Food and Agriculture Organization, as well as a 2003 report from Australia’s national science agency, found that regular fresh citrus consumption is protective against a huge array of illnesses, including reducing the risk of esophageal, mouth, and stomach cancers by 40-50 percent and reducing stroke risk by nearly 20 percent.
An orange has more than 170 different phytonutrients and more than 60 flavonoids, many of which have been shown to have anti-inflammatory, anti-tumor, and blood-clot-inhibiting properties, as well as strong antioxidant activity. One example, the flavonoid hesperidin, has strong anti-inflammatory properties, lowers high blood pressure and cholesterol in animal studies, as well as potentially treating osteoporosis, and is the object of much ongoing research.
Citrus consumption has benefits against arthritis, asthma, Alzheimer's disease, cognitive impairment, Parkinson's disease, macular degeneration, diabetes, gallstones, multiple sclerosis, cholera, gingivitis, respiratory problems, cataracts, ulcerative colitis, and Crohn's disease. And if that long list isn’t enough, citrus fruits may also be protective against obesity.
Real Vitamin C
Citrus fruits’ most well known component is vitamin C, the most widely consumed nutritional supplement in the U.S. after multivitamins. Yet studies show that vitamin C in supplemental pill form does not have the same antioxidant effects as when consumed from fresh citrus or juice, likely due to complex interactions with the many other antioxidants available in citrus, as shown in a 2007 study in the British Journal of Nutrition.
Vitamin C and other antioxidants protect our cells from damage by free radicals, which form in our body as a result of respiration and metabolism. Free radicals cause inflammation in the body, damage our DNA, and cause cholesterol to become “sticky” and adhere to the walls of arteries, leading to cardiovascular disease. In fact, vitamin C is so critical to life that most animals can produce it themselves, but not so with humans, who must consume it. It is also important for our immune system to function properly.
Another powerful antioxidant in citrus fruits is limonin. A potent anti-carcinogen, it remains in the body up to 24 hours, which is 3 to 6 times longer than similar compounds from tea, according to a 2005 study by U.S. Department of Agriculture scientists. Limonin is mainly found in the zest, or outside peel, of citrus fruits. Zest can be obtained from grating the peel of a lemon or orange. Always wash fruit well in fresh cold water before grating, and choose organic when possible to avoid possible pesticide residue.
Use and Storage
Citrus are winter fruits that grow in warm climates and then are shipped to colder zones. Most are harvested from November through May, but California’s Valencia Orange is called a “summer” orange because its harvest runs from February to October. In the U.S., the biggest citrus growing areas include Florida (oranges, mandarins, grapefruit, lemons), Southern California (oranges, mandarins, grapefruit, lemons, and limes), southwestern Arizona (oranges, satsumas), southern Texas (grapefruit), and southeastern Louisiana (satsumas). About 80 percent of U.S.-grown citrus comes from Florida, and much of that is made into juice.
Pick firm oranges without soft spots. An exception is the Satsuma tangerine, which tends to have a puffy peel when it is ready to eat. Ripe oranges may not be totally orange, but could have a green tinge to them. Oranges that are grown in colder regions tend to be more orange, while oranges grown in hotter areas send green chlorophyll to their outer skin to protect from sunburn. Green oranges still taste sweet. Oranges can be stored at room temperature for about two weeks or refrigerated for up to several months.
A medium orange has only about 60 calories yet provides 116 percent of the Daily Value for vitamin C; 12 percent of dietary fiber; 10 percent folate; 7 percent vitamin B1; 7 percent potassium; 6 percent vitamin A; and 5 percent calcium.
Most citrus can be simply washed, peeled, and eaten out of hand or added to salad. The outer peel of the orange is both delicious and fragrant—try grating a little in your yogurt or salad. To juice citrus: roll a room temperature orange or lemon on the counter first to soften it, then cut in half and juice. The pulp contains much of the fiber so don’t strain it if you want all the health benefits citrus has to offer.