Because of the limited benefits provided by pharmaceuticals in the treatment and prevention of common cold, people often turn to natural products like vitamin C, zinc, or herbs.  The antiviral drug oseltamivir only reduces cold symptom duration by 0.55 days in otherwise healthy adults.  Can natural options do better? Let’s see what research reveals.

Several studies and a published review of the literature provides some answers.  Keep in mind that prevention and treatment are considered different goals.  Many common natural products are more appropriate for prevention of the common cold while others are more effective at reducing the duration and/or severity (relief or treatment is not just about duration but also about symptom
severity)  of the common cold. Rarely is a single remedy suited for both instances; find out which is which in the overview below:

Vitamin C:  Of 7 trials, one study found that in the early symptom stage using a dose of 8 grams per day significantly reduced the duration of cold symptoms compared to a dose of 4 grams.  None of the other 6 trials showed any treatment benefits, even when the same dosage was used.  It’s difficult to draw any conclusions from this information.

In 30 studies assessing prevention, a very slight reduction in the number of colds was seen.  There was no reduction in severity of symptoms; however, the duration of colds was reduced by 8 percent, which is only somewhat meaningful, assuming a 12-day duration can be reduced to 11 days.  The daily dosage was 1 gram or more.

One other interesting finding was that when dealing with the added stress of cold weather or intense exercise, Vitamin C in doses of up to 2000 mg per day was shown to help to reduce the incidence of colds.

Echinacea:  In 6 trials that evaluated Echinacea purpurea, symptom severity was reduced in 4 of the 6 trials.  The duration of symptoms was also reduced in all but one of the trials.

There were also two trials assessing prevention which found no reduction in the number of colds and when someone caught a cold neither the symptom severity nor the dur5636925576_0a5783edc7_oation were reduced.

Ginseng:  There are no studies evaluating ginseng as a treatment for common cold; however, four studies have assessed the preventive benefits of two types of ginseng, American and Asian ginseng.  The chemical constituents in the two ginsengs are very similar, but Asian ginseng is considered warming to the body which is very different from the cooling effect imparted by American ginseng.
Three studies evaluated an extract of American ginseng that is sold in Canada as Coldfx.  Two of these studies found no reduction in the number of colds or the duration or severity of symptoms.  The third study found no reduction in the number of colds, but the duration of colds was reduced from 16.5 to 10.8 days.

One study evaluated Asian ginseng for prevention of common cold.   Those who took Asian ginseng for 2-4 months experienced far fewer colds than the placebo group, especially in the 3rd and 4th months.

Probiotics:  No trials were found that evaluated probiotics for the treatment of common cold symptoms.  However, there were 6 trials that assessed preventive benefits of probiotics using different strains and concentrations as measured by colony forming units.  The number and severity of colds was reduced in only one of the 6 studies.

Zinc:  There is very little data on the use of zinc for prevention; however, 13 trials for the treatment of common cold were found.  A zinc nasal spray was evaluated in 4 trials and was successful in reducing symptom duration and severity in 2 of the 4 studies.  Zinc lozenges were more consistently beneficial, showing a reduction in both duration and severity when using higher doses of 13 to 23 mg per lozenge every 2 hours.

Zinc trials that were not successful were criticized for using formulations that included citric or tartaric acids, sorbitol, and/or mannitol.  Apparently all these bind to and inactivate elemental zinc.

29039244921_bdbeec7f45_mAllicin:  Garlic cloves contain 5 to 9 mg of allicin which is inactivated by cooking.  Most extracts contain lower amounts of allicin.  However, one study that used a high dose of allicin (180 mg) daily for 12 weeks reduced the incidence of colds by 64% and reduced duration of symptoms as well.  Safety data on this high dose of allicin is not available but the only side effect reported was “malodorous belching.”

Herbal Formulas:  There are a number of proprietary herbal formulations on the market that can be found in the supplement isles of stores.  Only one, ImmuneDx, has any research data to support its use to maintain healthy immune function.  The data showed that ImmuneDx significantly increases the production of both T and B lymphocytes and increases the activity of macrophages.   Another ImmuneDx study was undertaken over a 4-month winter that was not specifically looking at common cold but rather at the maintenance of immune health.  The results demonstrated a significant benefit in maintaining healthy immune function compared to placebo.

Conclusion:  Given the lack of conventional options for the prevention and treatment of colds, and the fact that roughly 40% of reported sick days are the result of common cold, you might be wise to consider one or more of the above natural options to stay healthy this fall-winter-spring.