Oranges: Treasure trove of Health benefits

Oranges are an excellent source of vitamin C. They are also a very good source of dietary fiber. In addition, oranges are a good source of B vitamins including vitamin B1 and folate as well as vitamin A, calcium and potassium.

1. In recent research studies, the healing properties of oranges have been associated with a wide variety of phytonutrient compounds. These phytonutrients include citrus flavanones(types of flavonoids that include the molecules hesperetin andnaringenin), anthocyanins, hydroxycinnamic acids, and a variety of polyphenols. When these phytonutrients are studied in combination with orangesâ€"vitamin C, the significant antioxidant properties of this fruit are understandable.


2. You may already know that oranges are an excellent source ofvitamin Câ€"just one orange supplies 116.2% of the daily value for vitamin Câ€"but do you know just how important vitamin C and oranges are for good health? Vitamin C is the primary water-soluble antioxidant in the body, disarming free radicals and preventing damage in the aqueous environment both inside and outside cells. Inside cells, a potential result of free radical damage to DNA is cancer. Especially in areas of the body where cellular turnover is especially rapid, such as the digestive system, preventing DNA mutations translates into preventing cancer. This is why a good intake of vitamin C is associated with a reduced risk of colon cancer.

Free radical damage to other cellular structures and other molecules can result in painful inflammation, as the body tries to clear out the damaged parts. Vitamin C, which prevents the free radical damage that triggers the inflammatory cascade, is thus also associated with reduced severity of inflammatory conditions, such as asthma, osteoarthritis, and rheumatoid arthritis.

Free radicals also oxidize cholesterol. Only after being oxidized does cholesterol stick to the artery walls, building up in plaques that may eventually grow large enough to impede or fully block blood flow, or rupture to cause a heart attack or stroke. Since vitamin C can neutralize free radicals, it can help prevent the oxidation of cholesterol.

Vitamin C, which is also vital for the proper function of a healthy immune system, is good for preventing colds and may be helpful in preventing recurrent ear infections.

3. Consuming vitamin C supplements does not provide the same protective benefits as drinking a glass of orange juice, shows research by Italian researchers in the Division of Human Nutrition at the University of Milan, Italy (Guarnieri S, Riso P, et al., British Journal of Nutrition).

Seven healthy test subjects were given each of three drinks, two weeks apart: blood-orange juice containing 150 milligrams of vitamin C, fortified water containing 150 milligrams of vitamin C, and a sugar and water solution containing no vitamin C. Blood samples were collected immediately before the drink was consumed, then every hour for 8 hours, and finally 24 hours after consumption of each drink.

4. A 248-page report, "The Health Benefits of Citrus Fruits," released December 2003 by Australian research group, CSIRO (The Commonwealth Scientific and Industrial Research), reviews 48 studies that show a diet high in citrus fruit provides a statistically significant protective effect against some types of cancer, plus another 21 studies showing a non-significant trend towards protection.

Citrus appears to offer the most significant protection against esophageal, oro-phayngeal/laryngeal (mouth, larynx and pharynx), and stomach cancers. For these cancers, studies showed risk reductions of 40-50%.

The World Health Organization's recent draft report, "Diet, Nutrition and the Prevention of Chronic Disease," concludes that a diet that features citrus fruits also offers protection against cardiovascular disease due to citrus fruits--folate, which is necessary for lowering levels of the cardiovascular risk factor, homocysteine; their, potassium, which helps lower blood pressure, protecting against stroke and cardiac arrhythmias; and the vitamin C, carotenoids and flavonoids found in citrus fruits, all of which have been identified as having protective cardiovascular effects.

5. In animal studies and laboratory tests with human cells, compounds in citrus fruits, including oranges, called limonoids have been shown to help fight cancers of the mouth, skin, lung, breast, stomach and colon. Now, scientists from the US Agricultural Research Service have shown that our bodies can readily absorb and utilize a very long-acting limonoid called limonin that is present is citrus fruits in about the same amount as vitamin C.

In citrus fruits, limonin is present in the form of limonin glucoside, in which limonin is attached to a sugar (glucose) molecule. Our bodies easily digest this compound, cleaving off the sugar and releasing limonin.

In the ARS study, 16 volunteers were given a dose of limonin glucoside in amounts ranging from those that would be found in from 1 to 7 glasses of orange juice. Blood tests showed that limonin was present in the plasma of all except one of the subjects, with concentrations highest within 6 hours after consumption. Traces of limonin were still present in 5 of the volunteers 24 hours after consumption!

6. The ARS team is now investigating the potential cholesterol-lowering effects of limonin. Lab tests indicate that human liver cells produce less apo B when exposed to limonin. Apo B is a structural protein that is part of the LDL cholesterol molecule and is needed for LDL production, transport and binding, so higher levels of apo B translate to higher levels of LDL cholesterol.

7. A class of compounds found in citrus fruit peels called polymethoxylated flavones (PMFs) have the potential to lower cholesterol more effectively than some prescription drugs, and without side effects, according to a study by U.S. and Canadian researchers that was published in the Journal of Agricultural and Food Chemistry.

In this study, when laboratory animals with diet-induced high cholesterol were given the same diet containing 1% PMFs (mainly tangeretin), their blood levels of total cholesterol, VLDL and LDL (bad cholesterol) were reduced by 19-27 and 32-40% respectively. Comparable reductions were also seen when the animals were given diets containing a 3% mixture of two other citrus flavonones, hesperidin and naringin.

8. Oranges' health benefits continue with their fiber; a single orange provides 12.5% of the daily value for fiber, which has been shown to reduce high cholesterol levels thus helping to prevent atherosclerosis. Fiber can also help out by keeping blood sugar levels under control, which may help explain why oranges can be a very healthy snack for people with diabetes. In addition, the natural fruit sugar in oranges, fructose, can help to keep blood sugar levels from rising too high after eating. The fiber in oranges can grab cancer-causing chemicals and keep them away from cells of the colon, providing yet another line of protection from colon cancer. And the fiber in oranges may be helpful for reducing the uncomfortable constipation or diarrhea in those suffering from irritable bowel syndrome.

In addition to oranges' phytonutrients, vitamin C and fiber, they are a good source of thiamin, folate, vitamin A (in the form of beta-carotene), potassium and calcium.

9. Want to reduce your risk of calcium oxalate kidney stones? Drink orange juice. A study published in the British Journal of Nutrition found that when women drank 1/2 to 1 litre of orange, grapefruit or apple juice daily, their urinary pH value and citric acid excretion increased, significantly dropping their risk of forming calcium oxalate stones.

10. An orange a day may help keep ulcers away, according to a study published in the Journal of the American College of Nutrition. In this study, researchers evaluated data from over 6,000 adults enrolled in the Third National Health and Nutrition Examination Survey. Study participants with the highest blood levels of vitamin C had a 25% lower incidence of infection withHelicobacter pylori (H. pylori), the bacterium responsible for causing peptic ulcers and in turn, an increased risk for stomach cancer. Researchers are uncertain whether H. pylori lowers blood levels of vitamin C or if high blood levels of vitamin C help protect against infection--either way, eating an orange or drinking a glass of orange juice each day may help prevent gastric ulcers. Lead researcher in this study, Dr. Joel A. Simon at the San Francisco VA Medical Center, urges people who have tested positive for H. pylori to increase their consumption of vitamin C-rich foods since this may help them combat H. pyloriinfection.

11. Consuming foods rich in beta-cryptoxanthin, an orange-red carotenoid found in highest amounts in oranges, corn, pumpkin, papaya, red bell peppers, tangerines, and peaches, may significantly lower one's risk of developing lung cancer. A study published in the September 2003 issue of Cancer Epidemiology, Biomarkers and Prevention reviewed dietary and lifestyle data collected from over 60,000 adults in Shanghai, China. Those eating the most crytpoxanthin-rich foods showed a 27% reduction in lung cancer risk. When current smokers were evaluated, those who were also in the group consuming the most cryptoxanthin-rich foods were found to have a 37% lower risk of lung cancer compared to smokers who ate the least of these health-protective foods.

12. New research published in the American Journal of Clinical Nutrition adds to the evidence that enjoying a daily glass of freshly squeezed orange juice can significantly lower your risk of developing rheumatoid arthritis.