Vitamin C has often been associated with helping to alleviate symptoms of the flu and colds, such as coughing, sore throat and runny nose, because of its antioxidant properties that strengthen the immune system. Eating oranges is a good way to increase your vitamin C intake. However, controversy exists as to whether vitamin C in oranges is helpful in reducing or curing the common cold except in certain cases.
Oranges originated in Southeast Asia, and today they thrive in many countries including Portugal, Spain, North Africa and the United States, which is the world’s largest producer. Three basic types of orange include sweet, loose-skinned and bitter. Sweet oranges are large with skin that is difficult to remove. Seedless varieties, such as the navel, Valencia and the blood orange are best eaten raw. Loose-skinned oranges are easy to peel and include the mandarin orange family. Bitter oranges, used in marmalade, are too sour to eat raw.
Oranges, despite their beneficial vitamin C content, may have no effect on preventing the common cold or helping to reduce the duration and severity of symptoms. If cold weather or heavy exercise has placed a drain on your immune system, vitamin C may be of benefit. Researchers at the Australian National University used 29 trial comparisons involving 11,077 study participants to analyze the effects of high doses of vitamin C – 200 mg or more daily – to reduce the occurrence, length and severity of the common cold.
Results of all the trials, published in the “Cochrane Database of Systematic Reviews,” found a consistent reduction in incidence and duration of colds in 8 percent of adults and 13.5 percent of children. In five trials involving participants exposed to extreme physical stress, including soldiers, skiers and marathon runners, vitamin C reduced the risk of contracting a cold by one-half. Seven trials showed no benefits in length or severity of colds. One trial reported some advantage from an 8-g dose at the onset of symptoms – equal to the amount of vitamin C in 11 oranges – but no advantage to doses up to 4 g of vitamin C daily, which is more than four times the RDA. Conclusions of the study showed an advantage of vitamin C for persons who undergo strenuous physical exercise or in cold environments but, to reap these benefits, you would need to consume about 30 oranges a day.