Posted by kathryn in All In A Day's Work, Health News and Seasonal Health

Every few months it seems there’s a different story about echinacea. One study “proves” it works, and then two months later along comes another that trashes the herb.

Last week, results from a University of Connecticut (UConn) study were published, saying that echinacea reduces the chances of catching the common cold by 58 percent and reduces the duration of a cold by 1.4 days. Moreover echinacea, taken in conjuction with vitamin C, reduced the incidence of colds by 86 per cent.

This research is a meta-analysis, which combined the results of fourteen other studies, examined them together and came up with a list of conclusions. As the lead author of the study, Assistant Professor of Pharmacy Practice Craig Coleman says:

“The take home message from our study is that Echinacea does indeed have powerful cold prevention and cold treatment benefits. The significance of that finding becomes clear when you consider Americans suffer from one billion colds annually and spend about $1.5 billion annually for doctor’s visits and another $2 billion annually on non-prescription cough and cold treatments.”

New England Journal of Medicine study

This research also included results from the 2005 New England Journal of Medicine (NEJM) study that found against the efficacy of echinacea. The NEJM study was widely reported around the world and led to significantly reduced sales of echinacea. Nutraingredients reports that in Europe, sales fell from the 2003 peak of €6.1m, to €4.9m in 2005.

The methodology of the NEJM study has been widely questionned by herbalists, and also the current UConn study. In particular the study used a dose of echinacea more than three times lower than recommended . They also innoculated subjects with rhinovirus, which is only one of the more than 200 viruses capable of causing the common cold.

Species does matter

Echinacea is a genus of plants that contains a number of different species . The research into echinacea is confusing because groups use different species and also different parts of the plants – stalks and leaves, roots, or flowers. While all this research is reported under the banner of “echinacea”, not all species or preparations of echinacea are equally medicinally effective.

There are many, many products containing echinacea that are currently available. They often contain different species, different parts of the plant and recommend different doses. This compounds the confusion and contradictory results that are found in “echinacea” research.

While a large-scale study would confirm the best practices to use, this is unlikely to happen due to lack of funding.

Echinacea products in Australia

Here in Australia products tend to use either one, or both of two species: Echinacea angustifolia and Echinacea purpurea . Different parts of the plants are used, although products tend to contain either the root or flowering tops of the herb.

Current research indicates it’s the root of these two species which is the most medicinally effective, with the flowering tops of Echinacea purpurea coming second. The roots are also the most expensive parts of the plant and therefore often not used.

At this time of year I use loads of echinacea in clinic, to both treat persistent colds and also as a preventative. I find, at the correct dose and with the correct preparation , it’s very effective. Many of the retail brands are excellent, but you need to look at the labels as not all echinaceas are created equal.

Photograph by Jill Doughtie under the terms of a creative commons license

03 July, 2007