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Immunity – Colds & Flu

Immunity – Colds & Flu

Altern Med Rev. 2007 Mar;12(1):25-48.

Colds and influenza: a review of diagnosis and conventional, botanical, and nutritional considerations.Roxas M, Jurenka J.


The common cold is the leading cause of doctor visits in the United States and annually results in 189 million lost school days. In the course of one year the U.S. population contracts approximately 1 billion colds. Influenza infection is still a leading cause of morbidity and mortality, accounting for 20-25 million doctor visits and 36,000 deaths per year in the United States. Conventional therapies for colds and flu focus primarily on temporary symptom relief and include over-the-counter antipyretics, anti-inflammatories, and decongestants. Treatment for influenza also includes prescription antiviral agents and vaccines for prevention. This article reviews the common cold and influenza viruses, presents the conventional treatment options, and highlights select botanicals (Echinacea spp., Sambucus nigra, larch arabinogalactan, Astragalus membranaceous, Baptisia tinctoria, Allium sativa, Panax quinquefolium, Eleutherococcus senticosus, Andrographis paniculata, olive leaf extract, and Isatis tinctoria) and nutritional considerations (vitamins A and C, zinc, high lactoferrin whey protein, N-acetylcysteine, and DHEA) that may help in the prevention and treatment of these conditions.


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.1 Other trials have reported that taking vitamin C in high amounts (2 grams per hour for 12 hours) can lead to rapid improvement of influenza infections.2-3 Such high amounts, however, should only be used under the supervision of a healthcare professional.  Long-term high doses of vitamin C can deplete the nutrient copper levels in the body.


Echinacea has long been used for colds and flu. Double-blind trials in Germany have shown that infections associated with flu-like symptoms clear more rapidly when people take echinacea.4  Echinacea appears to work by supporting the immune system. The usual recommended amount of echinacea is 3–5 ml of the expressed juice of the herb or tincture of the herb or root, or 300 mg of dried root powder three times per day.


The effect of a syrup made from the berries of the black elderberry on influenza has been studied in a small double-blind trial.5 Sambucol was shown to be effective in vitro against 10 strains of influenza virus. People receiving an elderberry extract (four tablespoons per day for adults, two tablespoons per day for children) appeared to recover faster (by 3-4 days) than did those receiving a placebo.


Sambucol products, in addition to its antiviral properties, have been shown to activate the healthy immune system by increasing inflammatory cytokine production6. The authors of this study conclude that Sambucol might therefore be beneficial to the immune system activation and in the inflammatory process in healthy individuals or in patients with various diseases. It is likely that Sambucol could also have an immunoprotective or immunostimulatory effects.


1.  Renker K, Wegner S. Vitamin C-Prophylaxe in der Volkswertf Stralsund. Deutsche Gesundheitswesen 1954;9:702–6.

2. Klenner FR. The treatment of poliomyelitis and other virus diseases with vitamin C. South Med Surg 1949;111:210–4.

3.  Pauling L. Vitamin C, the Common Cold and the Flu. San Francisco: W. H. Freeman & Company, 1976 [review].


4.  Braunig B, Dorn M, Limburg E, et al. Echinacea purpurea radix for strengthening the immune response in flu-like infections. Z Phytother 1992;13:7–13 [in German].

5.  Zakay-Rones Z, Varsano N, Zlotnik M, et al. Inhibition of several strains of influenza virus in vitro and reduction of symptoms by an elderberry extract (Sambucus nigra L) during an outbreak of influenza B Panama. J Altern Complement Med 1995;1:361–9.

6. Eur Cytokine Netw. 2001 Apr-Jun;12(2):290-6. The effect of Sambucol, a black elderberry-based, natural product, on the production of human cytokines: I. Inflammatory cytokines.

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