December 21, 2005

Echinacea and the Common Cold

I have heard that echinacea, an herbal remedy, works well in the treatment of the common cold. Is there any evidence to back up its use in this situation?

The common cold, although a nuisance, is generally a benign and self-limited illness. It is caused by a group of viruses known as the rhinoviruses. Apart from the well-known symptoms of a stuffy/runny nose, blocked ears, and sneezing, the common cold can be the forerunner of significant medical consequences in the very old, the very young, and individuals with underlying chronic diseases and poor immunity responses. These latter problems are much more significant in patients who have influenza, which is characterized by fever as well as muscle and joint pains.

Because it occurs so frequently, the common cold has become socially important. People from various backgrounds have suggested various pills and potions in the hope that something may be found to be a cure. Even the illustrious and brilliant Linus Pauling, the chemist who won the Nobel Peace Prize, suggested large doses of vitamin C as both prevention and cure for the common cold. Although these claims were never proved in the clinical setting, many people still sometimes take dangerously high doses of vitamin C, believing this to be a cure for the common cold. In some instances, excessive vitamin C may trigger the formation of kidney stones. It reminds me of the saying repeated by colleagues and patients: ?When you have a cold, the time it takes to be cured is 7-14 days with medication, or one to two weeks without medication or intervention!?

1550 page28Echinacea was first used by North American Indians as a treatment for various infections and wounds. These preparations became popular as treatment for the common cold in the nineteenth century. In the 1960s the supplement boom brought echinacea back into popularity in the United States and Europe as a cold remedy. The question was still being asked as to whether it really worked. A number of clinical studies were done, mainly in Europe, to assess whether echinacea was effective. These studies were mainly sponsored by the industries that produced the preparation, and were not designed adequately to ensure that the outcomes were scientifically sound and not just chance or placebo-related. It was thought that echinacea may have a more specific effect on the immune cells and could stimulate the release of substances that may help with immunity. Unfortunately, these postulated effects did not change the clinical outcomes of the conditions tested.

A controlled, randomized clinical study was undertaken between 2002 and 2004 to test whether carefully defined preparations of echinacea were indeed effective against rhinovirus infections and the common cold and its symptoms. The study was thoroughly designed so that the correct numbers of subjects (people) were studied to ensure that the conclusions drawn would be accurate. Other aspects that were included in trial (study) design were randomization (selection) and a blinded, or placebo (noneffective), treatment group for comparison; this method helps to show that whatever the outcome of the study may be, it is grounded on sound evidence and not happenstance. Volunteers were infected with the virus, and treatment with echinacea was compared to treatment with placebo. Symptoms were assessed, immunity was monitored, and the extracts of echinacea were carefully analyzed to ensure the presence of active substances.

The results of this study showed that echinacea preparations did not help to prevent infections with the common cold virus; it further showed that objective symptoms and immunity responses were not improved by the use of echinacea. The evidence showed no positive influence on the immune system, as has been claimed in the past. The study attempted to evaluate the substances perceived to be active components in echinacea. There may possibly be variations or combinations that were not evaluated in this study, as the therapeutic substances may have been derived from different portions of the plant. It is also important to note that only the common cold rhinovirus was studied. Therefore, conclusions cannot be drawn about the effect of echinacea on other viruses. It would be important that those who contest the outcome of this study conduct similar well-designed scientific studies to evaluate any claims to the contrary. It is further noteworthy that the occurrence of side effects was similar in the study and placebo groups. These were mild, of short duration, and mainly gastrointestinal in nature.

1550 page28The study quoted answers the questions of the effectiveness of echinacea in prevention and treatment of the common cold. It also raises the issues related to the use of medications, interventions, and treatments of every kind. It is essential to examine the evidence for claims that are made regarding treatment and also to assess the validity of the scientific method used to reach those conclusions. This can be summarized as the ?evidence-based approach.? In adopting this method, it is necessary to evaluate the study (or trial) design, the methods and procedures used, and whether or not strict ethical codes were in place. When one evaluates data relating to health interventions, it is also vital that the results are able to be reproduced in various population groups and genders. This adds to the base of evidence that a particular treatment is effective and appropriate.

It is reassuring to see that supplements and other remedies are now being subjected to objective scrutiny and scientific evaluation. Because medications may originate naturally (e.g., from plants), this does not equate to efficacy. The converse is true: medications derived through advanced technology and syntheses require equally strict testing and validation before they are used and prescribed. (It is a real blessing that many of the tried-and-tested remedies are of plant origin, e.g., digoxin, aspirin, vincristine, quinine, etc.).

Despite such monitoring, and also regulatory bodies, problems arise; Vioxx is still very much on our radar screen. There is a new debate on the horizon regarding a novel medication for diabetes. Because of observed side effects on the cardiovascular system, there is need for further study and evaluation to determine safety prior to any thought of releasing it for use.

Evidence is important and should guide the use and applications of therapies, even in the treatment of the common cold.

Allan R. Handysides, M.B., Ch.B., F.R.C.P. (c), is director of the General Conference Health Ministries Department; Peter N. Landless, M.B., B.Ch., M.Med., F.C.P.(SA), F.A.C.C., is ICPA executive director and associate director of Health Ministries.

Send your questions to: Ask the Doctors, Adventist Review, 12501 Old Columbia Pike, Silver Spring, Maryland, 20904. Or you may send your questions via e-mail to [email protected]. While this column is provided as a service to our readers, Drs. Landless and Handysides unfortunately cannot enter into personal and private communication with our readers. We recommend that you consult with your personal physician on all matters of your health.