DOES IT WORK? BACKGROUNDFor the past three and a half years, the evidence for different herbs and supplements has been examined here. This will be the last of this series, although a book of the columns will be published mid-2012 by Glasnevin Publishing. In this final column, I'd like to leave you with some general guidance about herbal remedies.
People have been using herbal remedies for thousands of years, but this doesn’t necessarily mean they are all useful. Some are effective for specific conditions, others are poisonous, and still others will do little more than waste your money. For example, St John’s wort has good evidence to support its effectiveness for mild depression, while Aristolochia species have caused the deaths of hundreds of people. Meanwhile, new herbs appear on the market all the time with little or no evidence to guide people.
The complexity here is reflected in the number of products available. One report in the US a few years ago found that 1,400 different species of herbs were available in more than 30,000 different products.
Many products contain several herbs. A market analysis published earlier in 2011 found that multi-herb products dominate this market and are predicted to “race ahead” of single-herb remedies. This makes it even more difficult to determine if a product works or is good value for money. Products may contain several herbs with similar
reputations, but it becomes difficult to know if enough of any of them is present in these mixtures to have an effect. The potential for interactions, both good and bad, also arises.
For this reason, products with a single herb offer the best chance of getting a clearer understanding of their evidence. Uncovering that evidence can then be a challenge. As with many topics, the internet provides much information – some of it good, and some of it bad.
Discernment is vital when searching the internet, especially for health information. Be critical. If a website recommends a herb and is also selling it (as three-quarters of the sites are), be wary. If a website claims a herbal remedy will cure everything, surf away. If it sounds too good to be true, it probably is too good to be true.
To help when searching the web for health information, various accreditations are available. Websites agree to abide by a code of conduct and in return can display a certification logo. One is the Health On the Net (HON) Foundation, a not-for-profit organisation based in Switzerland. In general, websites with such logos should be trustworthy (but check out what the logo really means).
The best type of evidence for the effectiveness and safety of herbs, supplements or medicines are controlled clinical trials. These are increasingly available for herbal remedies and published in peer-reviewed journals. However, these are not written for popular consumption, and often provide so much detail that even busy professionals don’t have time to examine them. For this reason, systematic reviews are conducted to summarise the available research. These are designed to remove as much bias as possible from the conclusions.
One of the best sources of systematic reviews is the Cochrane Library, available at TheCochrane Library.com. This is produced by independent professionals and available both in great detail and in plain language summaries. Reviews of several dozen herbs are available, and more are added each month.
PROBLEMATIC ASPECTS
The impression is often given that natural is safe. Hemlock, the death cap mushroom (Amanita phalloides) and deadly nightshade (Atropa belladonna), should be enough to remind us that nature can be dangerous. Consuming enough capsaicin from chilli peppers will kill you. Many herbs have adverse effects, and unfortunately some herbal remedies (especially those bought over the internet) can be impure. Batches of “herbal viagra” in particular have been found to be contaminated with pharmaceuticals.
Herbal remedies can be a way to avoid expensive medicines. For short-term conditions, these may be an option. But for serious conditions, or if symptoms persist, it is important not to avoid medical attention. Self-diagnosis has its limitations.
RECOMMENDATIONS
Although thousands of herbs are used, only a few dozen have received extensive research. Many have not been studied in controlled trials and trying them is, at best, guesswork. For others, a few studies may be available.
Be wary of general claims about products being “scientifically proven” unless specific references are given to that evidence. Also, ask your doctor or pharmacist about herbs or supplements you are using or considering. They should have access to the growing number of professional databases addressing herbal remedies (such as NaturalDatabase.com). It is also important that they know about all the herbs, supplements and medicines you are taking as some of them can interact with one another.
If a herb works, it does so because it contains chemicals that affect our bodies. In that way, they are naturally occurring drugs that should be taken with due caution.
Dónal O’Mathúna has a PhD in pharmacy, researching herbal remedies, and an MA in bioethics, and is a senior lecturer in the School of Nursing Human Sciences, DCU. His
Irish Times
columns will be published mid-2012 by Glasnevin Publishing.
Series concluded
