Herbs are often prescribed according to traditional medical systems. These systems may seem strange and confusing to newcomers, and may present significant language barriers. To those not accustomed to the concepts, they may seem like nonsense. But, traditional medical systems are just like any human scientific paradigm.
You have to be trained to understand them. There are some phenomena which they explain and predict satisfactorily, yielding tremendous health benefits. There are some phenomena that they are unable to explain or predict, frustrating doctors and patients. This is no different from the biomedical paradigm.
Once any of us has grown up or been trained in a given conceptual system, it can be difficult to take another system seriously. The very entities which hold metaphysical and epistemic validity seem like fanciful constructs. In reality, all entities are constructs, which seem real only because of our repeated use of them and because those around us accept their validity. To those who are raised or educated with the concepts of qi or kapha, they seem just as real as gravity and oxygen do to westerners.
To a scientist who wishes to transcend the paradigm of his training and win new insights into the natural world and new opportunities to shape that world to our liking, the basis of metaphysical validity must be a concept’s potential to explain and predict empiric phenomena.
Traditional herbal systems and herbs for weight loss are no more nonsensical than Newtonian physics. We all realize that while Newtonian physics has been disproved and supplanted by modern physics, it is still very useful. The relation between traditional medical systems and the biochemical model is similar but more problematic because they have been developed separately by multiple distinct communities.
The biomedical model has had difficulty explaining and predicting certain phenomena associated with traditional systems, e.g. acupuncture. Therefore, the biomedical model has not been able to completely supplant the other systems.
Will a unifying model of human pathophysiology emerge? Perhaps not. Through most of human history distinct medical systems have coexisted, alternately cooperating and competing. Dominance by a single system is the exception. Complete dominance for any system seems unlikely.
Modern herbalism in America is highly syncretic, borrowing concepts from the biomedical system as well as multiple herbal systems. For the time being patients and practitioners must navigate multiple conceptual worlds. Yet it is often in the interstices between paradigms that the most fruitful ideas can take form.
Synergy and Simpling: how herbal medicines are blended
One of the biggest conceptual differences between conventional medicine and herbalism is the attitude toward the simultaneous use of multiple medications. With rare exceptions (combination antimicrobials or combination hypoglycemic) conventional medicine prefers the patient to use a few drugs as possible. Herbalism takes the opposite approach, believing that the action of herbs is synergistic.
Keep in mind that herbs contain multiple active constituents and have multiple physiological actions. Herbs are traditionally used in combination. Herbs are combined into formulas according to traditional systems. Some herbs are traditionally used together or thought to combine well together. Some formulas have become classics because clinical experience has found them to be very efficacious.
Each herbal system has its own rules of blending (See the panel for an example of a very basic system). When not using traditional formulas, herbs are blended specially for the individual patient. Blending is an art that requires a knowledge of material medica and skill in evaluating the patient. No two patients receive the same herbs and the blends are constantly adjusted. This makes evaluation by clinical trials problematic to say the least.
Today, most herb use in the United States is on a folk basis. Patients buy herbs at a shop without consulting a trained herbalist. They purchase either single herbs (simples) or modern, eclectic blends not based on a traditional system, but combining herbs from around the world. The blending is done by herbalists who work for manufacturers and is based on a combination of traditional lore, ethnographic study and modern clinical studies.
Evaluating Safety and Efficacy of Herbs
Evaluating the safety and efficacy of herbs is a highly controversial issue. This is a difficult topic, and deserves to be considered in an open-minded and sympathetic way. We must all remain respectful of those who disagree with us about methodology or conclusions.
The single greatest obstacle to careful evaluation of herbs is scarcity of resources. If the average drug in the US cost $500 million to develop and bring to market, it will be a long time before a substantial portion of the world of herbalism is validated by the accepted standards of the biomedical model. This is not to say that we should not make an effort to apply as many of the techniques of the drug development system to herbs as we can. Most users would welcome more resources for controlled investigation of herbs. But any person who denies themselves or others the opportunity to improve their health through existing knowledge and techniques of herbalism is foolish.
Other obstacles are methodological. The use of herbs in traditional systems does not lend itself to controlled studies because herbs are used in combinations that are continually adjusted for each patient. Herbs are usually used in conjunction with lifestyle changes or vitamin supplements.
Much of the research that is done on herbs is of limited usefulness because it is focused on pharmacognosy, with the intent of identifying active constituents as a step toward developing a patentable drug, not for the sake of evaluating the efficacy of the herb in its traditional use.
A recent troubling development is increased investigation of adverse reactions and drug interactions of herbs. It it not that herbalist do not want this information or think it is important. The controversial part is that this type of research may receive much more funding than efficacy research. Imagine the misleading picture that would be created if research into conventional drugs only focused on their safety and not efficacy. Inevitably some research would reveal safety problems, while no research would show efficacy. If research focused only on the hundreds of thousands who die as a result of conventional medications and not the millions whose lives are saved or improved, it would create a very misleading picture.
For these reasons the standards of evidence-based medicine which should be applied to conventional medications are not always appropriate when applied to herbs. History, literature, tradition, ethnobotany, pharmacognosy, as well as pharmacologic, animal, small, or uncontrolled studies may be combined with double-blind, placebo-controlled studies to make reasonable safety and efficacy claims as well as sound clinical decisions.