Public and scientific interest in traditional herbal medicine has been reawakened in the West and research into this area has greatly increased in recent years. Just how effective are these products and how do we know they are safe to take? Food Today takes a look at what the science says about some of the more popular herbal remedies.

Active ingredients in plants

Plants contain active constituents that help protect them from insects, moulds and other parasites, and also against excessive ultraviolet radiation from the sun. Many of these plant components, either individually or in combinations, have been found to have stimulatory, calming and medicinal effects in humans.

Herbal remedies have been used for thousands of years building upon the experience of Pythagoras, Galen and Hippocrates and the observations of doctors and herbalists throughout the ages. Many people in developing countries rely on herbal medicines to meet their health needs. In Europe and North America, a revival of interest in herbal products has been stimulated by an improved understanding of how herbs work and by the setting of standards for safety, quality and reliability of herbal preparations.

Some of the more popular herbal preparations include:

Chamomile - Often taken as a tea, chamomile may aid digestion and has anti-inflammatory effects.

Echinacea - this is a popular remedy in those hoping to boost their immune systems and fight off a cold. Some studies have reported that Echinacea may help in fighting upper respiratory tract infections.

Gingko biloba - The seeds and fruits of the Gingko tree have been used as medicines in China since 2800 BC Some studies suggest that gingko biloba may improve circulation, memory and mental functioning, especially in older people.

St. John's Wort (Hypericum perforatum) - St. John's Wort has been used for over a thousand years in the treatment of several conditions including kidney and lung disorders. It has been widely used for treating anxiety, depression and sleep disorders.

Valerian - Valerian has been used to treat insomnia, anxiety and nervousness and acts as a muscle relaxant. Several small studies have shown that valerian may induce sleepiness, however further large-scale studies are needed.

The World Health Organization has recognised the potential value and of herbal products to health care needs worldwide and is encouraging more systemic clinical assessments and higher standards of cultivation and preparation.

Neither food nor drugs

Herbal products are neither food nor drugs and many countries lack specific regulations to govern these products.

When using herbal products, consumers should not assume that all herbal medicines are safe just because they are natural. These products contain active ingredients that have similar effects to drugs and medicines and similar levels of care need to be taken when consuming them. From time to time there are reports of serious side effects from herbal preparations. For example, in the UK, the Medicines Control Agency recently expressed concern about the safety of "kava kava" after its use was linked to 30 cases of liver damage.

As with other forms of self-medication, herbal remedies may hide a serious underlying medical condition. For example, depression can be caused by a number of serious illnesses including heart disease and thyroid disorders.

The use of herbs may also affect the outcome of surgical procedures. A review of eight commonly used herbs including Echinacea, garlic, ginkgo, ginseng, St. John's wort, and valerian found that surgical complications were more common when patients were using the herbs. Garlic, ginkgo, and ginseng may cause bleeding while ginseng can lower blood sugar levels in some people. St. John's wort, and valerian all have effects on blood levels of prescription drugs.

It is strongly recommended that people wishing to take herbal supplements seek the advice of their medical practitioner and always notify their doctors if they are taking herbal preparations. While the area of herbal medicines offers great potential, research is still in its infancy and much more work is needed to determine the effects of traditional herbal medicines on well being and quality of life.

References

• Newall, C. A.; Anderson, L. A. and Phillipson, J. D. (1996) Herbal Medicines. A guide for health-care professionals. The Pharmaceutical Press, London, pp. 1-296
• WHO Regional Publications (1998) Guidelines for the appropriate use of herbal medicines. Western Pacific Series No. 23. Regional Office for the Western Pacific, Manila. WHO, Geneva. pp. 1-79
• Wills, R. B. H.; Bone, K. and Morgan, M. (2000) Herbal products and active constituents, modes of action and quality control. Nutrition Research Reviews 13 47-77 July 11, 2001 Journal of the American Medical Association.
• Pietta, P. and Pietta, A. Fitomedicine e Nutrienti. Richiutto (Ed), Bussolengo (Verona), 1998;pp1-510:2

FOOD TODAY 03/2002