What do you do for the common cold? While upping your intake of vitamin C has been the age-old answer, zinc and echinacea now seem to be the alternative remedy of choice. There have been many, many studies carried out on the use of vitamin C, which luckily have been nicely summarized in a huge meta-study. This investigated the six biggest UK trails, which included over 5000 episodes of illness. Patients were treated with either with, on average, one milligram per day vitamin C or a placebo from the first sign of the cold, but none of the studies could show a significant difference in either symptom severity or duration of illness. This study does report that in general, in the UK, plasma vitamin C levels are low in the population, especially in males. Four studies with males of school age who were supplemented with daily vitamin C did show a significant reduction in the incidence of infections. This would indicate that although high doses of vitamin C at the start of a cold do not help, having a healthy level of vitamin C on a daily basis may be beneficial in the resistance to infection (Hemila H, 1997).
A few studies have been carried out on the efficacy of extracts of the plant Echinacea purpurea on cold symptoms. Of three studies, two showed significant results, whereby if therapy was started as soon as symptoms were felt, and dampening of symptoms as ascertained by either personal report (Hentshcel C, 1997) or doctor’s record (Brikeborn RM, 1999). These studies both used commonly available formulas with the former study using the preparation Esberitox N (fluid extract of radix echinacea 15mg, radix baptisiae 20mg and herba thujae 4mg), and the latter using either Echinaforce (95% herba and 5% radix), Echinacea purpurea concentrate (as before but seven times more concentrated) or ‘special Echinacea purpurea radix preparation’. From these studies Esberitox N, Echinaforce and Echinacea purpurea concentrate helped to alleviate some of the symptoms of a cold, when taken as soon as they are noticed, with little to no side effects. However, a study of long-term twice daily use of 4mL fluid extract of Echinacea purpurea in people with a history of frequent infection with the cold virus did not find a reduction in the number of colds or respiratory infections (Grimm W, 1999).
Zinc preparations are also popularly used for treating cold symptoms. The scientific rational behind the use of zinc is that rhinoviruses, which cause the common cold, attach to the epithelium in the nose via the receptor for intracellular adhesion molecule-1 (ICAM-1), part of the bodies own defense system. Zinc can also attach to ICAM-1 receptors, thus is thought to act by blocking the availability of these receptors to the rhinovirus. A meta-study of ten clinical trails using zinc gluconate, prepared according to homeopathic principals, shows that when taken as soon as symptoms are felt, there is a significant beneficial effect (Godfrey JC, 1984). A closer look at the precise effects of zinc compared 100 patients who took either 13.3mg of zinc two hourly, in the form of zinc gluconate lozenges, or a placebo. This study found that all symptoms resolved quicker with the zinc lozenges, over a median of four and a half days compared to seven and a half days with no medication. The zinc group had fewer days with coughing, headache, hoarseness, nasal congestion, nasal drainage and sore throat, although no difference was shown for fever, muscle ache, scratchy throat or sneezing. The drawback of this study was that patients in general found the lozenges made them nauseous and had a bad-taste (Mossad SB, 1996). A similar study in children (Macknin ML, 1998), did not however find any significant differences between taking zinc or placebo lozenges. The problems in these studies were scientific – is ingested zinc effective at blocking ICAM-1 receptors in the nose, and practical – many report the taste of the preparations unbearable. To overcome this, present studies are investigating zinc nasal gel with one recent one (Hirt M, 2000) showing that over the counter Zicam significantly reduced the duration of symptoms from an average of nine days to an average of two and a half days, as long as the gel was administered within the first day of symptoms occurring.
So in conclusion: Vitamin C = debatable as an immediate remedy, Echinacea = may be helpful, Zinc nasal spray = could be very beneficial if taken early. As always, consult a medical professional before taking any of these formulations, especially if you are already on medication.
Brinkeborn RM, Shah DV, Degenring FH. Exhinaforce and other Echinacea fresh plant preparations in the treatment of the common cold. A randomized, placebo controlled, double-blind clinical trial. Phytomedicine. 1999; 6 (1): 1-6
Godfrey JC, Godfrey NJ, Novick SG. Zinc for treating the common cold: review of all clinical trails since 1984. Alt Ther Health Med. 1996; 2 (6): 63-72
Grimm W, Muller HH. A randomized controlled trail of the effect of fluid extract of Echinacea purprea on the incidence and severity of colds and respiratory infections. Am J Med. 1999; 106 (2): 138-43
Hemila H. vitamin C intake and susceptibility to the common cold. BJ Nutrition. 1997; 77 (1); 59-72
Hentschel C, Zeppelin HH, Kohnen R, Kohler G, Wustenberg P, Ernst E. Clinical efficacy of Esberitox in common cold – results of a (GCP) randomized double-blind placebo-controlled multicener study (presented at the 4th Annual Symposium on Complementary Healthcare, 10-12 Dec, 1997, Exeter). Focus on Alt and Comp Ther. 1997; 2(4): 189
Hirt M, Nobel S, Barron E. Zinc nasal gel for the treatment of common cold symptoms: a double-blind, placebo-controlled trial. Ear Nose Throat J. 2000 Oct; 79 (10):778-80, 782
Macknin ML, Piedmont M, Calendine C, Janosky J, Wald E. Zinc gluconate lozenges for treating the common cold in children: a randomized controlled trial. JAMA. 1998; 279 (24): 1962-7
Mossad SB, Macknin ML, Medendorp SV, Mason P. Zinc gluconate lozenges for treating the common cold. A randomized, double-blind, placebo-controlled study. Ann Int Med. 1996; 125 (2): 81-8