Herbalism

Herbalism, also known as phytotherapy, is folk and traditional medicinal practice based on the use of plants and plant extracts.

Finding healing powers in plants is an ancient idea. People in all continents have long used hundreds, if not thousands, of indigenous plants for treatment of various ailments dating back to prehistory. There is evidence that Neanderthals living 60,000 years ago in present-day Iraq used plants for medicinal purposes (found at a burial site at Shanidar Cave, Iraq, in which a Neanderthal man was uncovered in 1960. He had been buried with eight species of plants) These plants are still widely used in ethnomedicine around the world.

The first generally accepted use of plants as healing agents were depicted in the cave paintings discovered in the Lascaux caves in France, which have been Radiocarbon dated to between 13,000 - 25,000 BCE.

Over time and with trial and error, a small base of knowledge was acquired within early tribal communities. As this knowledge base expanded over the generations, tribal culture developed into specialized areas. These 'specialized jobs' became what are now known as healers or Shaman. Plants have an almost limitless ability to synthesize aromatic substances, most of which are phenols or their oxygen-substituted derivatives such as tannins. Most are secondary metabolites, of which at least 12,000 have been isolated, a number estimated to be less than 10% of the total. In many cases, these substances (esp. alkaloids) serve as plant defense mechanisms against predation by microorganisms, insects, and herbivores. Many of the herbs and spices used by humans to season food yield useful medicinal compounds.

The use of and search for drugs and dietary supplements derived from plants have accelerated in recent years. Pharmacologists, microbiologists, botanists, and natural-products chemists are combing the Earth for phytochemicals and leads that could be developed for treatment of various diseases. In fact, many modern drugs have been derived from plants.

The use of herbs to treat disease is almost universal among non-industrialized societies. A number of traditions came to dominate the practise of herbal medicine in the Western world at the end of the twentieth century:

The Western, based on Greek and Roman sources,
The Ayurvedic from India, and
Chinese herbal medicine (Chinese herbology).

Many of the pharmaceuticals currently available to Western physicians have a long history of use as herbal remedies, including opium, aspirin, digitalis, and quinine.

Biological background

All plants produce chemical compounds as part of their normal metabolic activities. These can be split into primary metabolites, such as sugars and fats, found in all plants, and secondary metabolites found in a smaller range of plants, some only in a particular genus or species.

The autologous functions of secondary metabolites are varied. For example, as toxins to deter predation, or to attract insects for pollination. It is these secondary metabolites which can have therapeutic actions in humans and which can be refined to produce drugs. Some examples are inulin from the roots of dahlias, quinine from the cinchona, morphine and codeine from the poppy, and digoxin from the foxglove.

As of 2004, the National Center for Complementary and Alternative Medicine started to fund clinical trials into the effectiveness of herbal medicine.

Some surveys of scientific herbal medicine can be found in Evidence-based herbal medicine edited by Michael Rotblatt, Irwin Ziment; Philadelphia: Hanley & Belfus, 2002, and Herbal and traditional medicine: molecular aspects of health, edited by Lester Packer, Choon Nam Ong, Barry Halliwell; New York: Marcel Dekker, 2004.

Popularity

A survey released in May 2004 by the National Center for Complementary and Alternative Medicine focused on who used alternative medicine (CAM), what was used, and why it was used. The survey was limited to adults age 18 years and over during 2002 living in the United States. According to this recent survey, herbal therapy, or use of natural products other than vitamins and minerals, was the most commonly used CAM therapy (18.9%) when all use of prayer was excluded.

Examples of herbal medicine

Examples of some commonly used herbal medicines:

Artichoke and several other plants reduced total serum cholesterol levels in preliminary studies.
Black cohosh and other plants that contain phytoestrogens (plant molecules with estrogen activity) have some benefits for treatment of symptoms resulting from menopause.
Echinacea extracts limit the length of colds in some clinical trials, although some studies have found it to have no effect.
Garlic lowers total cholesterol levels, mildly reduces blood pressure, reduces platelet aggregation, and has antibacterial properties..
Nigella sativa (Black cumin)is a generalist medicinal plant used for diverse ailments such as cough, pulmonary infections, asthma, influenza, allergy, hypertension and stomach ache. The seeds are considered carminative, stimulant, diuretic and galactogogue. It is often taken with honey. Seed powder or oil is externally applied for eruptions of skin.
Peppermint tea for problems with the digestive tract, including irritable bowel syndrome and nausea.
St John's wort, though dangerous in incorrect doses, is more effective than a placebo for the treatment of mild to moderate depression in some clinical trials.
Valerian root can be used to treat insomnia.

Dangers

A common misconception about herbalism and the use of 'natural' products in general, is that 'natural' equals safe. However many plants have chemical defence mechanisms against predators that can have adverse or lethal effects on humans. Examples are poison hemlock and nightshade, which can be deadly. Herbs can also have undesirable side-effects just as pharmaceutical products can. These problems are exacerbated by lack of control over dosage and purity. Furthermore, if given in conjunction with drugs, there is danger of 'summation', where the herb and the drug have similar actions and add together to make an 'overdose'. In animals, there are other dangers. There may be residues in food from farm animals (e.g. eggs, milk, meat) or danger of 'doping' in competition animals. The latter may also apply to human athletes.

Name confusion

The common names of herbs may be shared with others with different effects. For example, in one case in Belgium in a TCM-remedy for losing weight, one herb was swapped for another resulting in kidney damage. One variety of the herb causes elevated blood pressure and increased heart rate, versus another variety for the weight-loss remedy, the varieties are differentiated by the suffix in the Latin names.

International standards

The legal status of herbal ingredients varies by country. For example, Ayurvedic herbal products may contain levels of heavy metals that are considered unsafe in the U.S., but heavy metals are considered therapeutic in Ayurvedic medicine.

Medical interaction

Those wishing to use herbal remedies should first consult with a physician, as some herbal remedies have the potential to cause adverse drug interactions when used in combination with various prescription and over-the-counter pharmaceuticals. Dangerously low blood pressure may result from the combination of an herbal remedy that lowers blood pressure together with prescription medicine that has the same effect. In particular, many herbs should be avoided during pregnancy. Physicians may not be the best sources of information because most have no knowledge of herbal medicine. There is little known about interactions of herbal remedies with pharmaceuticals because, contrary to pharmaceutical medicine, there is no official system, database, or hotline to report and publish adverse interactions, so even herbalists may not be aware of adverse interactions.

A meta-analysis published in the Journal of the American Medical Association (JAMA) reported the following: "The overall incidence of serious adverse drug reactions (ADRs) was 6.7% (95% confidence interval ^*, 5.2%-8.2%) and of fatal ADRs was 0.32% (95% CI, 0.23%-0.41%) of hospitalized patients. We estimated that in 1994 overall 2,216,000 (1,721,000-2,711,000) hospitalized patients had serious ADRs and 106,000 (76,000-137,000) had fatal ADRs, making these reactions between the fourth and sixth leading cause of death." (JAMA. 1998;279:1200-1205)

References

NIH Institute and Center Resources, National Institute of Health.
More Than One-Third of U.S. Adults Use Complementary and Alternative Medicine, National Center for Complementary and Alternative Medicine Press release. May 27, 2004.
(nccam.nih.gov/news table 1 on page 8)
Herbs for serum cholesterol reduction: a systematic view, Thompson Coon JS and Ernst E. 2003 Jun
www.ncbi.nlm.nih.gov
www.ncbi.nlm.nih.gov
www.herbaled.org
www.ncbi.nlm.nih.gov
Herbs to avoid during pregnancy

External links

New England Journal of Medicine editorial about the risks of alternative medicine
University of Maryland site about alternative medicine: uses, possible prescription drug interactions, and possible nutrient depletions
Website of the National Herbalists Association of Australia
Center for Complementary and Alternative Medicine (National Institutes of Health)
National Institute for Medical Herbalists Website for the governing body in the United Kingdom

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