The cold and flu season is no treat. With this year bringing added challenges, consider taking a few simple actions to boost your body’s immunity and keep illness at bay. Exercising regularly, limiting alcohol, caffeine, and sugar, eating healthy meals that contain plenty of fruits and vegetables, and drinking lots of water are the best places to start. Vitamin C is a frequently recommended supplement for use during the common cold. Learn more about this water-soluble vitamin.
HOW TO USE IT
For otherwise healthy, non-smoking adults, the recommended dietary allowance (RDA) for vitamin C is 75 mg per day for women and 90 mg per day for men. Most clinical vitamin C studies have investigated the effects of a broad range of higher vitamin C intakes (100–1,000 mg per day or more), often not looking for (or finding) the “optimal” intake within that range. Some vitamin C experts propose that adequate intake be considered 200 mg per day because of evidence that the cells of the human body do not take up any more vitamin C when larger daily amounts are used.
However, in the case of the common cold, a review of published trials found that larger intakes of vitamin C may be more effective than smaller amounts, at least for this condition.
COMMON COLD/SORE THROAT
A review of 21 controlled trials using 1 to 8 grams of vitamin C per day found that “in each of the twenty-one studies, vitamin C reduced the duration of episodes and the severity of the symptoms of the common cold by an average of 23%.” The optimum amount of vitamin C to take for cold treatment remains in debate but may be as high as 1 to 3 grams per day, considerably more than the 120 to 200 mg per day that has been suggested as optimal intake for healthy adults. A review of 23 controlled trials found that vitamin C supplementation produces a greater benefit for children than for adults. The same review found that a daily amount of 2 grams or more was superior to a daily amount of 1 gram at reducing the duration of cold symptoms.
Vitamin C has antiviral activity, and may help prevent viral infections or, in the case of the common cold, reduce the severity and duration of an infection.
Dockworkers given 100 mg of vitamin C each day for ten months caught influenza 28% less often than did their coworkers not taking vitamin C. Of those who did develop the flu, the average duration of illness was 10% less in those taking vitamin C than in those not taking the vitamin.
WHERE TO FIND IT
Citrus fruits, broccoli, red peppers, currants, Brussels sprouts, parsley, potatoes, and strawberries are good sources of vitamin C. Rose hips, harvested from rose bushes and sold as a supplement, are particularly high in vitamin C.
Although scurvy (severe vitamin C deficiency) is uncommon in Western societies, many doctors believe that most people consume less than optimal amounts. Fatigue, easy bruising, and bleeding gums are early signs of vitamin C deficiency that occur long before frank scurvy develops.
BEST FORM TO TAKE
Vitamin C can be taken as ascorbic acid (a weak acid) or in buffered forms (such as sodium ascorbate, calcium ascorbate, or other mineral ascorbates). Buffered forms may be less likely to produce gastrointestinal distress, but they may be more likely to deliver excessive amounts of minerals. There is some limited evidence to suggest that vitamin C from natural sources (such as citrus extract) is more bioavailable than synthetic vitamin C. Therefore, if synthetic vitamin C is taken, it may be wise to obtain additional flavonoids and supporting nutrients from eating more fruits and vegetables. Fat-soluble forms of vitamin C (such as ascorbyl palmitate) are not preferred since vitamin C is naturally a water-soluble compound.
INTERACTIONS WITH SUPPLEMENTS, FOODS, & OTHER COMPOUNDS
Intake of large amounts of vitamin C can deplete the body of copper, an essential nutrient. People should be sure to maintain adequate copper intake at higher intakes of vitamin C. Copper is found in many multivitamin-mineral supplements. Vitamin C increases the absorption of iron and should be avoided by people with iron overload diseases. Vitamin C helps recycle the antioxidant, vitamin E. People with the following conditions should consult their doctor before supplementing with vitamin C: glucose-6-phosphate dehydrogenase deficiency, iron overload (hemosiderosis or hemochromatosis), history of kidney stones, or kidney failure.
Vitamin C is not known to reduce the effectiveness or interact negatively with any drugs. Please find detailed information on interactions here.
Information courtesy of Health Notes. Find full list of references here.