Echinacea as a dietary supplement

• DEFINITION: Herbal product promoted as a dietary supplement for specific health benefits.
• PRINCIPAL PROPOSED USE: Treatment of colds and flu
• OTHER PROPOSED USES: Chronic bronchitis (acute flare-ups), genital herpes
• PROBABLY NOT EFFECTIVE USES: Cold and flu prevention, general immune support

Overview

The decorative plant Echinacea purpurea, or purple coneflower, has been one of the most popular herbal medications in the United States and Europe for over a century. Native Americans used the related species E. angustifolia for various problems, including respiratory infections and snake bites. Herbal physicians among the European colonists quickly added the herb to their repertoire. Echinacea became tremendously popular toward the end of the nineteenth century when businessman H. C. F. Meyer promoted an herbal concoction containing E. angustifolia. The garish, exaggerated, and poorly written nature of his labeling helped define the characteristics of a “snake oil” remedy.

Serious manufacturers also developed an interest in echinacea. By 1920, the respected Lloyd Brothers Pharmaceutical Company of Cincinnati, Ohio, counted echinacea as its best-selling product. In Europe, physicians took up the American interest in E. angustifolia with enthusiasm. Demand soon outstripped the supply coming from the United States, and in an attempt to rapidly plant echinacea locally, the German firm Madeus mistakenly purchased a quantity of E. purpurea seeds. This historical accident is why most modern echinacea belongs to the purpurea species instead of angustifolia. Another family member, E. pallida, is also used.

Echinacea was the leading cold and flu remedy in the United States until it was displaced by sulfa antibiotics. Ironically, antibiotics are not effective for colds, whereas echinacea appears to offer some real help. Echinacea remains the primary remedy for minor respiratory infections in Germany.

Uses and Applications

In Europe, and increasingly in the United States, echinacea products are widely used to treat colds and flu. The best scientific evidence about echinacea concerns its ability to help one recover from colds and minor flu more quickly. It also appears to significantly reduce symptoms. Echinacea may also “abort” a cold if taken at the first sign of symptoms. However, taking echinacea regularly throughout the cold season is unlikely to offer benefits, as evidence suggests it does not prevent colds.

It was earlier believed that echinacea acted by stimulating the immune system. Test-tube and animal studies had found that various constituents of echinacea can increase antibody production, raise white blood cell counts, and stimulate the activity of key white blood cells. However, later studies have tended to cast doubt on this theory. The fact that regular use of echinacea does not appear to help prevent colds (or genital herpes) also somewhat argues against an immune-strengthening effect. Thus, it can only be said that it is not understood how echinacea affects cold symptoms.

Echinacea has been proposed for the treatment and prevention of other acute infections too. One small double-blind study found that the use of an herbal combination containing echinacea enhanced the effectiveness of antibiotic treatment for acute flare-ups of chronic bronchitis. However, two other studies failed to find benefit for ear infections in children.

Finally, echinacea is frequently proposed for general immune support. However, there is some reason to think that it is not effective for this purpose.

Scientific Evidence

Reducing the symptoms and duration of colds. Double-blind, placebo-controlled studies enrolling more than one thousand people have found that various forms and species of echinacea can reduce cold symptoms and help with a faster recovery. The best evidence regards products that include the above-ground portion of E. purpurea.

In one double-blind, placebo-controlled trial, eighty people with early cold symptoms were given either an above-ground E. purpurea extract or placebo. The results showed that those who were given echinacea recovered significantly more quickly–only six days in the echinacea group versus nine days in the placebo group.

Another study found evidence that above-ground E. purpurea can reduce the severity of cold symptoms but that E. purpurea root may not be effective. In this double-blind trial, 246 people with recent onset of respiratory infection were given either placebo or one of three E. purpurea preparations: two formulations of a product made of 95 percent above-ground herb (leaves, stems, and flowers) and 5 percent root, and one formulation made only from the roots of the plant. The results showed significant improvements in symptoms such as runny nose, sore throat, sneezing, and fatigue with the above-ground preparations, but the root preparation was ineffective.

Symptom reduction with a whole-plant formulation of E. purpurea was seen in a double-blind, placebo-controlled study of 282 people. However, another double-blind, placebo-controlled study of above-ground E. purpurea, enrolling 120 people, failed to find benefits compared with placebo treatment. An even larger trial (407 participants) failed to find a widely used above-ground E. purpurea extract helpful for treating children with respiratory infections. The reasons for these negative outcomes are unclear.

In other studies, benefits were seen with a preparation of E. pallida root and an herbal beverage tea containing above-ground portions of E. purpurea and E. angustifolia (and some E. purpurea root extract). A double-blind, placebo-controlled study failed to find benefit with a dry herb product consisting largely of E. purpurea root and E. angustifolia root. Another study failed to find benefit with E. angustifolia root extract. The best supporting evidence for echinacea involves the above-ground portion or whole-plant extract of E. purpurea, but even here, the results are less than fully consistent.

“Aborting” a cold. A double-blind study suggests that echinacea not only can make colds shorter and less severe but also can stop a cold that is just starting. In this study, 120 people were given E. purpurea or a placebo as soon as they started showing signs of getting a cold.

Participants took either echinacea or placebo at a dosage of twenty drops every two hours for one day, then twenty drops three times a day for up to ten days of treatment. The results were promising. Fewer people in the echinacea group felt that their initial symptoms developed into “real” colds (40 percent of those taking echinacea versus 60 percent taking the placebo actually became ill). Also, among those who did get real colds, improvement in the symptoms started sooner in the echinacea group (four days instead of eight days). Both of these results were statistically significant.

Preventing colds. Several studies have attempted to discover whether the daily use of echinacea can prevent colds from even starting, but the results have not been promising. In one double-blind, placebo-controlled trial, 302 healthy volunteers were given an alcohol tincture containing either E. purpurea root, E. angustifolia root, or placebo for twelve weeks. The results showed that E. purpurea was associated with perhaps a 20 percent decrease in the number of people who got sick, and E. angustifolia with a 10 percent decrease. However, the difference was not statistically significant. This means that the benefit, if any, was so small that it could have been caused by chance alone.

Another double-blind, placebo-controlled study enrolled 109 people with a history of four or more colds during the previous year and gave them either E. purpurea juice or placebo for eight weeks. No benefits were seen in the frequency, duration, or severity of colds. Similar results were seen in four other studies that enrolled more than 350 people.

A study often cited as evidence that echinacea can prevent colds actually found no benefit in the 609 participants taken as a whole. Only by looking at subgroups of participants (a statistically questionable procedure) could researchers find any evidence of benefit, and it was still slight.

However, a later study using a combination product containing echinacea, propolis, and vitamin C did find preventive benefits. In this double-blind, placebo-controlled study, 430 children aged one to five years were given either the combination or placebo for three months during the winter. The results showed a statistically significant reduction in the frequency of respiratory infections. It is not clear what components of this mixture were responsible for the apparent benefits seen.

Patients with severe COVID-19 who took echinacea, in addition to medical treatments, seemed to recover more quickly. Researchers speculate that the supplement boosted the immune system's response. Because of this, researchers asserted that clinical trials were warranted. In a randomized, controlled study of 120 healthy adults ranging from eighteen to seventy-five, researchers investigated the impact of echinacea on upper respiratory illnesses, specifically COVID-19 infections. The test group received the echinacea supplement Echinaforce, which contains high doses of Echinaceapurpurea extract. Over several weeks this supplement was found to shorten the number of days individuals with SARS-CoV-2 had a fever. Individuals who took the supplement also spent fewer days in the hospital and experienced a significant reduction in viral load. Further research is needed to confirm these findings, but echinacea may be instrumental in treating and preventing upper respiratory illnesses.

Dosage

Echinacea is usually taken at the first sign of a cold and continued for seven to fourteen days. Longer-term use of echinacea is not recommended. The best (though not entirely consistent) evidence supports the use of products made from the above-ground portions of E. purpurea (specifically, the flowers, leaves, and stems). E. pallida root has also shown promise, but E. purpurea root appears to be ineffective.

The typical dosage of echinacea powdered extract is 300 milligrams three times a day. Alcohol tincture (1:5) is usually taken at a dosage of 3 to 4 milliliters (ml) three times daily, echinacea juice at a dosage of 2 to 3 ml three times daily, and whole dried root at 1 to 2 grams three times daily. There is no broad agreement on what ingredients should be standardized in echinacea tinctures and solid extracts.

In a 2003 analysis of available echinacea products, about 10 percent had no echinacea; about one-half were mislabeled as to the species of echinacea present; more than one-half the standardized preparations did not contain the labeled amount of standardized constituents, and the total milligrams of echinacea stated on the label generally had little to do with the actual milligrams of herb present. A subsequent analysis performed in 2004 by a respected testing organization also found many problems. While consumers began holding manufacturers to higher standards following this research, labeling inconsistencies and misleading products remained prevalent.

Many herbalists feel that liquid forms of echinacea are more effective than tablets or capsules because they believe part of echinacea’s benefit comes from the activation of the tonsils through direct contact. However, there is no real evidence to support this contention.

Finally, goldenseal is frequently combined with echinacea in cold preparations. However, there is no evidence that oral goldenseal stimulates immunity; traditional herbalists did not use it for this purpose.

Safety Issues

Echinacea appears to be generally safe. Even when taken in very high doses, it has not been found to cause any toxic effects. However, the National Center for Complementary and Integrative Health believes that taking echinacea in the short-term seems safe but the safety of long-term use is not yet known. Reported side effects are also uncommon and usually limited to minor gastrointestinal symptoms, increased urination, and mild allergic reactions. However, severe allergic reactions have occurred occasionally, some of them life-threatening. In Australia, one survey found that 20 percent of allergy-prone people were allergic to echinacea.

Other concerns relate to echinacea’s possible immune-stimulating properties. Immunity is a complex and delicate process. Excessively strong immune reactions can be dangerous, particularly for individuals with certain illnesses. Echinacea should be used only with caution (if at all) by persons with autoimmune disorders, such as multiple sclerosis, lupus, pemphigus vulgaris, and rheumatoid arthritis.

Furthermore, a late case report strongly suggests that the use of echinacea can trigger episodes of erythema nodosum (EN), an inflammatory condition that involves tender nodules under the skin. These nodules often arise after cold-like symptoms. In this report, a forty-one-year-old man took echinacea on four separate occasions when he thought he was developing a cold, and each time he developed EN instead. When he stopped using echinacea, he remained free of EN outbreaks for a full year of follow-up. The cause of EN is not known, but it involves increased activity of certain immune cells; echinacea has been observed to cause similar effects in the same immune cells, suggesting that the relationship is not coincidental.

One study raised questions about possible antifertility effects of echinacea. When high concentrations of echinacea were placed in a test tube with hamster sperm and ova, the sperm were less able to penetrate the ova. However, because it is not known whether this much echinacea can actually come in contact with sperm and ova when they are in the human body rather than a test tube, these results may not be meaningful in real life.

Animal studies of echinacea support its safety in pregnancy. One human study found a bit of evidence that the use of echinacea during pregnancy does not increase the risk of congenital abnormalities, but confirmatory research is needed.

Furthermore, studies dating to the 1950s suggest that echinacea is safe in children. Nonetheless, the safety of echinacea in young children and pregnant or nursing women cannot be regarded as established. In addition, safety in those with severe liver or kidney disease has not been established.

Two studies suggest that echinacea might interact with various medications by affecting their metabolism in the liver, but the significance of these largely theoretical findings remains unclear. A review of the research literature found no verifiable reports of drug-herb interactions with any echinacea product. Those taking echinacea should avoid any products containing caffeine, such as coffee, cola, and sports drinks.

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