Echinacea leads the pack with strong clinical and consumer support. Here's the latest.
While certainly unpleasant, symptoms of the common cold or flu are generally short-lived. But that doesn’t mean consumers need to take getting sick lying down. Many natural remedies on the market can help shore up good health to guard against the times when, inevitably, we will get sick. Among them, the botanical echinacea is perhaps the most well known, and for good reason.
The echinacea plant is indigenous to North America and was traditionally used by Native Americans for its health benefits. Often referred to by the common name of purple coneflower, there are three major species used medicinally: Echinacea purpurea, Echinacea angustifolia, and Echinacea pallida.1 Current studies indicate the plant’s benefits for the prevention and treatment of colds and flu, as well as for preventing complications arising from these viral infections.
Echinacea is also one of the top-selling botanicals in the United States, according to a recent report published last year in the American Botanical Council’s journal HerbalGram.2 Sales of echinacea in the mainstream retail channel (includes supermarkets, drugstores, mass-market retailers, and buyer’s clubs) surpassed $50 million in 2014-a 79% increase from 2013-making it the third top-selling medicinal herb behind horehound and cranberry. Echinacea also made the top-10 list in the natural channel, totaling over $7 million in retail sales.
These numbers are a tribute to echinacea’s popularity with consumers, who strongly believe in the plant’s ability to support immune health. It is also a testament to the research that has been performed on the botanical for prevention of colds and flu as well as related complications. While a recent review concluded that overall evidence of echinacea’s ability to prevent the common cold is weak (although there was evidence that echinacea reduces the incidence of cold episodes3), additional recent studies point to substantial positive effects from echinacea supplementation as a potent immune-system enhancer.
Clinical Evidence for Echinacea
A recent trial conducted in the Czech Republic by Karel Raus and colleagues aimed to evaluate the effectiveness of a hot drink (Echinaforce by A. Vogel Bioforce AG, Roggwil, Switzerland) containing echinacea (Echinacea purpurea) compared to the drug oseltamivir (the generic name for Tamiflu) against the influenza virus.4 In the double-blind, multicenter study, 473 patients with early influenza symptoms (onset of 48 hours or less) were randomized to treatment with oseltamivir (5 days) followed by placebo (5 days), or the echinacea-based hot drink for 10 days. After five days of treatment, the rate of recovery from illness for the echinacea group was 50.2%, while 48.8% of patients in the oseltamivir group recovered from influenza. At 10 days, 90.1% of those in the echinacea group had recovered, while 84.8% of those on oseltamivir recovered.
Based on the results of the trial, the investigators deemed the echinacea-based hot drink to be as effective as oseltamivir (the gold-standard treatment for influenza) for the early treatment of clinically diagnosed influenza virus infection.
Furthermore, influenza sufferers often develop additional complications frequently associated with the lower respiratory tract, a major cause for hospitalization. In the current study, the rate of complications in the oseltamivir group was 6.5%, but it was lower in the echinacea group, at 2.5%. Overall reported side effects were also lower with echinacea treatment, particularly indicated by a five-fold lower incidence of nausea and vomiting compared to oseltamivir. The reduced rate of complications and side effects attributed to echinacea make it a favorable option for the early treatment of influenza.
An earlier study evaluated the ability of Echinacea purpurea to prevent the common cold. In this large European study led by Martez Jawad of the Common Cold Centre at Cardiff University (Wales, United Kingdom), 755 healthy individuals received an alcoholic extract of Echinacea purpurea (Echinaforce; 0.9 ml of extract three times per day) or a placebo for four months.5 Over the four-month period, there were a total of 149 episodes (672 episode days) of the common cold in the echinacea-treated group versus 188 episodes (850 episode days) in the placebo group. The difference in episode days between groups was statistically significant. Furthermore, the difference in rate of recurrent infection was significantly lower with echinacea treatment than with placebo. In addition, the use of pain medication to treat cold-related symptoms was substantially higher in the placebo group than with echinacea therapy. The echinacea preparation also had an excellent safety profile comparable to the placebo treatment.
Francisco Di Pierro and colleagues from Velleja Research in Italy evaluated the ability of a standardized extract from the roots of Echinacea angustifolia (the branded ingredient Polinacea from supplier Indena in Milan, Italy) to prevent respiratory tract infections.6 The researchers conducted two pilot studies; one in adults with chronic respiratory issues (including asthma, chronic bronchitis, and respiratory insufficiency) and another in healthy children.
The first study looked at the ability of the echinacea preparation to reduce respiratory complications associated with ailments diagnosed as the common cold (secondary to the influenza and parainfluenza viruses) in adults with existing respiratory issues who received the flu vaccine. In other words, the researchers wanted to evaluate the ability of echinacea to enhance the immune response to the flu vaccine. The second study in children assessed the ability of the echinacea product to prevent or decrease the number of episodes of influenza or parainfluenza over a four-month period.
In the first study, adults aged 38–79 with diagnosed chronic respiratory issues were divided into one of three groups: group 1 received the flu vaccine only, group 2 received the echinacea product, while group 3 received both.6 Echinacea was administered for 90 days (2 tablets per day, with 100 mg of extract per tablet) for 15 days, followed by one tablet per day for the next 15 days and 1 tablet every other day for 60 days. Participants were monitored over a four-month period.
In the group receiving the vaccine only, 5 of 14 individuals developed cold-like symptoms, while three individuals experienced respiratory complications. In the echinacea group, 2 of 12 suffered from cold-like symptoms, and one individual developed respiratory complications. In the combination therapy group, only 1 of 12 participants developed cold-like symptoms, and none of the individuals developed complications. This indicated a protective effect of echinacea against influenza and parainfluenza and further suggests that echinacea may bolster the immune response associated with the flu vaccine.
The second study enrolled 34 healthy children between the ages of 9 and 15.6 Participants received the echinacea product (one tablet daily for 30 days followed by one tablet every other day for the next 60 days) or a B-complex vitamin on the same dosing regimen. Evaluation included the development of cold symptoms and the onset of respiratory complications over a four-month period.
Two of the 14 children in the echinacea group developed cold or flu symptoms, while in the group receiving B vitamins, 8 of 20 children developed cold or flu symptoms. None of the individuals in either group developed respiratory complications associated with their infections.
While larger trials are needed, these preliminary studies support a potential clinical benefit of echinacea for the prevention of cold and flu and indicate the plant’s ability to enhance the immune response associated with flu vaccination.
A new meta-analysis of randomized controlled studies confirms the benefit of echinacea in reducing the risk of recurrent respiratory tract infections and associated complications. Led by Andreas Schapowal from the Allergy Clinic in Landquart, Switzerland, the group of researchers identified studies with a primary endpoint of recurrent infection risk.7 After narrowing down their focus to 12 clinical studies on echinacea addressing this endpoint, six trials with a total of 2,458 participants met final inclusion criteria and were included in the analysis.
The results of the meta-analysis showed that echinacea extracts were significantly associated with reduced risk of recurrent respiratory tract infections. Furthermore, in individuals more susceptible to infections or with increased stress and immunological weakness, echinacea administration cut the risk of recurrent infections in half. Common complications such as pneumonia, ear infections, tonsillitis and pharyngitis were also less frequent in those taking echinacea. The authors concluded that the use of echinacea potently lowers the risk of recurrent infections and complications, and these benefits appear to be strongest in those most susceptible.
Immune-Stimulating, Anti-inflammatory, and Antiviral
Echinacea species confer their preventive benefits on colds and flu through several mechanisms. These include direct antiviral effects, immune-modulating benefits, and anti-inflammatory activity.
A study led by Margaret Ritchie of Napier University in Edinburgh, United Kingdom, aimed to examine the effects of supplementation with an ethanol extract of Echinacea purpurea for eight days in 30 volunteers by examining blood samples for changes in cytokine profiles.8 The research team drew blood on a daily basis and stimulated it with various inflammatory agents. Echinacea supplementation was found to reduce the levels of pro-inflammatory cytokines tumor necrosis factor-α (TNF-α) and interleukin-1-β (IL-1β) by up to 24% while increasing the levels of the anti-inflammatory cytokine interleukin-10 (IL-10) by 13% when compared to baseline values.
Further subgroup analyses performed by the authors also found differential effects in individuals with higher stress or greater susceptibilities to infection. For example, in those individuals treated with the echinacea extract during a stressful period or those individuals reporting greater than two colds per year, the echinacea extract caused a significant transient increase in interferon-γ (IFN-γ) levels of over 25%. As IFN-γ is a powerful activator of natural killer cell and macrophage activity, this is a highly beneficial effect in fighting off viral infections. These results together demonstrate that echinacea supports anti-inflammatory effects and further modulates the immune system to achieve higher levels of immune activity in individuals requiring additional protection.
Similar benefits in cytokine profiles have been shown for Echinacea angustifolia. Barbara Dapas and colleagues from the University of Trieste in Trieste, Italy, assessed the effects of an echinacea-based syrup given daily for four weeks in 10 healthy subjects aged 26–53 years.9 The investigators evaluated changes in cytokine expression in lymphocytes and monocytes (immunologically active white blood cells) in plasma samples by measuring levels in cellular messenger RNA. A fasting baseline blood sample was drawn each week for five weeks prior to commencement of the echinacea syrup. A further weekly blood sample was taken for the four-week trial period. Results indicated that levels of IL-2 and IL-8 increased, suggesting improved lymphocyte proliferation and neutrophil activation and thus enhanced immunological activity; in addition, levels of the pro-inflammatory cytokines TNF-α and IL-6 decreased.
A recently published review of the pharmacology of echinacea by Azadeh Manayi and colleagues from Tehran University of Medical Sciences (Iran) and the University of Saskatchewan (Saskatoon, Canada) affirms the herb’s immune modulating and anti-inflammatory benefits.10 The authors also reviewed cell studies demonstrating direct antiviral activities of echinacea against various viral agents, including human, avian, and swine-origin strains of influenza, while additional assays indicated that the extract tested had the ability to block viral entry into treated cells. Together, the multiple mechanisms of action of echinacea species make it an attractive botanical choice for immune support.
In addition to this trifecta of benefits supporting immune defenses, echinacea appears to have a very positive safety profile. In a recently published paper, Karin Ardjomand-Woelkart and Rudolf Bauer from the Institute of Pharmaceutical Sciences at the University of Graz (Graz, Austria) conducted a systematic review of literature on echinacea preparations for evidence of drug interactions, contraindications, adverse events, and duration of safe use.11 Based on their findings, the authors concluded that echinacea preparations are well tolerated and safe for children and adults alike.
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An Ounce of Prevention
Echinacea is a botanical that continues to show promise in preventing colds, flu, and related complications. The clinical results described here are extremely positive in that the difficulty associated with developing preventive treatments for the common cold and flu viruses stem from the fact that multiple viruses are implicated in symptoms. Vaccines can often miss their marks, as well, by not including active seasonal strains. The fact that echinacea supports immune health through multiple mechanisms makes it an effective primary or adjunct preventive measure with a high level of safety.
Sidebar: The Price of Poor Immune Health
Most will recover from the common cold and flu relatively quickly, so we may not always remember that these diseases can have significant health and economic consequences.
A study conducted by the Centers for Disease Control and Prevention (CDC), which looked at data from 1979–2001 from 500 hospitals across the United States, estimated that over 200,000 people are hospitalized each year from respiratory and other complications related to influenza virus12, while flu-associated deaths on a yearly basis ranged from 3,000–49,000 people between 1976–200613.
While the common cold is usually much milder in comparison, estimates suggest that there are more than one billion cases on a yearly basis, with an annual economic cost of $40 billion per year. The common cold accounted for more than 100 million visits to healthcare providers annually, leading to a cost of $20 billion per year due to missed work days.1 In both cases, effective preventive measures are of paramount importance.
1. Ross SM, “Echinacea purpurea: A proprietary extract of Echinacea purpurea is shown to be safe and effective in the prevention of the common cold,” Holistic Nursing Practice, vol. 30, no. 1 (January–February 2016): 54–57
2. Tyler Smith et al., “Herbal dietary supplement sales in US increase 6.8% in 2014," HerbalGram, Issue 107 (2015): 52–59
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4. RauÅ¡ K et al., “Effect of an echinacea-based hot drink versus oseltamivir in influenza treatment: A randomized, double-blind, double-dummy, multicenter, noninferiority clinical trial,” Current Therapeutic Research, Clinical and Experimental, vol. 77 (April 20, 2015): 66–72
5. Jawad M et al., “Safety and efficacy profile of Echinacea purpurea to prevent common cold episodes: A randomized, double-blind, placebo-controlled trial,” Evidence-Based Complementary and Alternative Medicine. Published online September 16, 2012.
6. Di Pierro F et al., “Use of a standardized extract from Echinacea angustifolia (Polinacea) for the prevention of respiratory tract infections,” Alternative Medicine Review: A Journal of Clinical Therapeutic, vol. 17, no. 1 (March 2012): 36–41
7. Schapowal A et al., “Echinacea reduces the risk of recurrent respiratory tract infections and complications: A meta-analysis of randomized controlled trials,” Advances in Therapy, vol. 32, no. 3 (March 2015): 187–200
8. Ritchie MR et al., “Effects of Echinaforce® treatment on ex vivo–stimulated blood cells,” Phytomedicine, vol. 18, no. 10 (July 15, 2011): 826–831
9. Dapas B et al., “Immunomodulation mediated by a herbal syrup containing a standardized echinacea root extract: A pilot study in healthy human subjects on cytokine gene expression,” Phytomedicine, vol. 21, no. 11 (September 25, 2014): 1406–1410
10. Manayi A et al., “Echinacea purpurea: Pharmacology, phytochemistry and analysis methods,” Pharmacognosy Reviews, vol. 9, no. 17 (January–June 2015): 63–72
11. Ardjomand-Woelkart K et al., “Review and assessment of medicinal safety data of orally used echinacea preparations,” Planta Medica. Published online October 5, 2015.
12. Centers for Disease Control and Prevention. Seasonal Influenza-Associated Hospitalizations in the United States. www.cdc.gov/flu/about/qa/hospital.htm. Accessed January 5, 2016.
13 Centers for Disease Control and Prevention. Key Facts about Influenza (Flu) & Flu Vaccine. https://www.cdc.gov/flu/. Accessed January 5, 2016.