Nutrition Column – is There Help for the Common Cold?

The cold season is here! It’s estimated that over 60 million of us this year will have colds severe enough to seek medical attention.

If you’re one of the unlucky ones and are coming down with or already have a nasty cold, you may be wondering how best to treat your symptoms. Are over-the-counter cold medications the only way to go, or do alternative remedies such as vitamin C, echinacea and zinc really help? Here’s the latest from research studies on the subject.

Vitamin C: Vitamin C has had a long association with the common cold – adequate intake of vitamin C is necessary to help fight infections and keep the immune system healthy. However, more than 60 studies that have evaluated the influence of vitamin C on the common cold have been inconclusive. Those that have seen positive results have tended to be smaller studies and with population groups that typically have low dietary intakes of vitamin C. For example, a recent study in the United Kingdom, where vitamin C intake generally is low, showed the group that took two vitamin C tablets daily from November to February had significantly fewer colds and colds of shorter duration than the group that took a placebo.

The recommended dietary allowance, or RDA, for vitamin C is 75 milligrams per day for women and 90 milligrams for men. Although no specific "magic" dosage of vitamin C has been shown to be optimal for treating cold symptoms, megadoses – more than 2,000 mg per day – can actually do more harm than good. In some instances, taking large amounts of vitamin C can cause side effects such as nausea, abdominal cramps and diarrhea.

Echinacea: Over the past several years, echinacea has become one of the hottest herbal remedies in the United States. While little research has been done in the United States, a 2001 German study found

echinacea was effective in alleviating symptoms more rapidly than the placebo in patients with common colds. However, two more recent studies, one in Germany and one in the United States, concluded that treating patients with echinacea did not significantly decrease the incidence, duration or severity of colds and respiratory infections.

Echinacea does not appear to cause adverse side effects when used by otherwise healthy people on an occasional short-term basis. Since possible adverse effects from long-term use have not been studied, most sources recommend that echinacea only be taken when symptoms of a cold first appear and then only for a week or two. Because echinacea is an immune-system stimulant, people with autoimmune diseases like lupus, multiple sclerosis and rheumatoid arthritis should not take the herb. It is also not recommended for pregnant or lactating women or for people taking corticosteroids and other immunosuppressants.

Zinc: Another alternative cold remedy is the use of zinc lozenges to help reduce the duration and severity of cold symptoms. The research on zinc’s effectiveness continues to be contradictory. For example a 2002 study published in the American Journal of Therapy showed that over the 3½ year period of the study, students taking zinc gluconate glycine lozenges had fewer and shorter colds and used fewer antibiotics to manage colds than those not using the lozenges. Also, a 2000 study published in the Annals of Internal Medicine showed that those who took a zinc lozenge every two to three hours, beginning with the first symptoms, had shorter colds than those who took a placebo. In contrast, a U.S. clinically controlled trial published in 2000 and 2001 in Clinical and Infectious Diseases found that zinc lozenges and nasal sprays did not help reduce the length or severity of cold symptoms among study participants when compared to subjects receiving placebos. It has been suggested that the different results seen may be due in part to differences in zinc ion availability among the various lozenge preparations used.

If you choose to take zinc to try to alleviate cold symptoms, you should be aware that, while a zinc deficiency can depress immune function, so can taking too much zinc. The RDA for zinc is 12 mg per day for adult women and 15 mg per day for adult men. Most experts recommend taking no more than 100 mg of zinc over the course of a day.

The bottom line is that additional research is still needed to better understand these alternative remedies and their effectiveness in fighting the common cold. While there is probably no harm in taking these supplements in moderate doses when you feel a cold coming on, they may be no more effective than frequent hand washing in helping ward off a cold.