In my last article, I looked at whether supplements are safe. Herbs are usually (not always) sold as supplements under US law, so in one sense they are largely a subset of supplements. And yes, supplements are safer than drugs, but what about herbs? Let's look at the reasons why herbs are generally safer than drugs.
But first, let's dispel a common myth-- herbs are NOT safe because they are “natural”. Water is natural, and people drown in it all the time. Lightning is natural, and so are moose on the highway, but they both kill surprising numbers of people every year. More to the point, Hemlock (Conium maculatum), Yew (Taxus baccata), and Deadly Nightshade (Atropa belladonna) are all completely natural herbs, and they are all highly poisonous.
So why are medicinal herbs generally safe? I believe that there at least three reasons: 1) centuries of experience, 2) safety margins, and 3) multiple pathways. So let's examine each of these factors in more detail.
Herbs have been readily available for thousands of years, and we have a great deal of experience with them. Herbal texts are reputed to date back some 3000 to 5000 years, and a lot has been written about their uses, contraindications, and side effects. Since herbs can be gathered anywhere, by anybody, there is every reason to use them, and every reason to report any experience, good or bad, to others who might use them as well. Contrast that to patented drugs, which are new, available from only one source, and practitioners using them have no way of knowing whether their own experience is usual or unusual, and no easy way of sharing their experience with other practitioners.
Every body is different, and reacts differently to different substances. Drug companies overcome this problem by statistical analysis, since most reactions follow a bell-shaped curve, where most people have similar reactions. They can then accurately forecast the number of people who might be helped (the center of the curve) against those who might not respond, or even be hurt (in the edges or “tails” of the curve). This gives them a sense of mathematical assurance that they can accurately balance profitability against risk. But this kind of risk balancing, while great for the drug company, is no comfort to the unlucky people at the edges of the curve.
Herbs, on the other hand, do not readily lend themselves to this kind of precise balancing of risk and reward. Herbs themselves can differ dramatically from one place to another, and from year to year, and batch to batch. While some companies try to overcome this problem by creating standardized extracts based on certain marker compounds, there is rarely (if ever) a single compound that defines an herb.
Because of the inherent variability of natural herbs, traditional use has favored herbs that offer wide margins of safety. Herbs that may be useful in some circumstances, but must be dosed and used very carefully to avoid harming the patient, have over the centuries generally fallen into disfavor as being too risky. As a result, most of the herbs that are in common use today have wide safety margins that make them less likely to cause harm. I wish the same could be said for drugs like warfarin, where the difference between a therapeutic dose and a fatal one can be very thin.
As I mentioned above, few if any herbs have a single compound that is entirely responsible for its therapeutic effect. Most have families of related compounds, which may all contribute to the effect. Dr. Andy Weil, speaking at Expo West 2012 last March, opined that the body knows which compounds to use, and only uses them as needed. That is perhaps the case, but I think it more likely that the body responds to many or all of the compounds, but in different ways. Because the body responds to different compounds to different degrees, a family of related compounds may deliver a more reliable, safe, and predictable response across the broad range of individuals than what you get with a single compound or drug. We build on this concept with our PortfolioTM formulation strategy.
I think that herbs, like drugs, need to be used with good sense and understanding. It doesn't help to assume they are always safe because they are “natural”, or that if a little is good, a lot is better. Rather, they should be used intelligently, and in traditional ways, where the benefits of experience, safety margins, and multiple pathways can be used to full advantage.