Along with the colder weather comes cold and flu season. In the United States, most colds occur during the fall and winter. Beginning in late August or early September, the rate of colds increases slowly over a few weeks and remains high until March or April, when it declines. The seasonal variation may relate to the opening of schools and to cold weather, which prompt people to spend more time indoors and increase the chances that viruses will spread from person to person.
While basic measures such as frequently washing hands and sleeping at least eight hours each night may reduce the risk of contracting a cold, several integrative therapies may also provide benefits.
Echinacea: Echinacea species belong to the aster family (Asteraceae) that originated in eastern North America. Of the nine identified species, only three are used as medicine. The roots and herbs of the species have been studied for potential immune benefits. Taking echinacea by mouth is often suggested as a treatment for the common cold. Echinacea may help reduce the length and severity of the common cold. Much research has focused on the potential benefits of echinacea for this purpose. Although most studies report positive effects, some recent high-quality trials found negative results in adults and children. More research is needed before a firm conclusion can be made.
Goldenseal: Goldenseal is one of the five top-selling herbal products in the United States. Studies on the effectiveness of goldenseal are limited to one of its main chemical ingredients, berberine salts. A small amount of berberine is actually present in most goldenseal preparations. Goldenseal has become a popular treatment for the common cold and upper respiratory tract infections, and is often added to echinacea in commercial herbal cold remedies. Berberine may have effects against bacteria and inflammation. However, due to the very small amount of berberine in most goldenseal preparations, it is unclear whether goldenseal contains enough berberine to have the same effects.
Zinc: Available studies report conflicting results on the impact of zinc on the common cold. Overall, studies suggest that if taken when symptoms begin, zinc may help treat cold symptoms. Effects are strongest in adults. Zinc gluconate is not recommended for sore throats. Further research is needed to clarify which zinc formulas are effective for reducing symptoms. More studies are needed before a firm conclusion may be drawn.
Green tea: Green tea is made from the dried leaves of Camellia sinensis, an evergreen shrub. Polyphenols, compounds found in green tea, have been shown to have antiviral effects. Early research suggests that specific green tea formulas may help prevent cold and flu symptoms. In children, drinking one to five cups daily has been linked to a reduced risk of developing the flu. More studies are needed to confirm these results.
For more information about integrative therapies for the common cold, please visit Natural Standard's Comparative Effectiveness Database.