Sunday April 9, 2006
Herbal safety issues
IN a recent report, the World Health Organization (WHO) states that there is widespread use of traditional medicine in all developing countries, while use of complementary and alternative medicine is increasing rapidly in developed countries.
The WHO has been actively involved in developing guidelines to regulate the quality and safe use of herbal medicines across the world. This article enumerates the various safety issues with herbs.
Herbs and safety
“Natural is safe” is a myth. Some of the plants in nature are toxic as well, or even deadly, if taken internally. Hence safety tests on herbs are necessary before they are recommended for use. Safety tests like pre-clinical pharmacology, toxicology, histopathological and biochemical investigations provide evidence of the safety profile of the herb. These safety tests follow the same protocols, which applies for conventional medicine.
While safety of herbs itself is one issue, contaminants in herbs is another. The commonly seen contaminants in herbs are heavy metals, pesticides and bacterial toxins. These contaminants, when consumed for the long-term, have toxic effects on the body. Tests like gas chromatography and atomic absorption spectrophotometry (AAS) on the raw material of herbs will establish the contamination and will help prevent the manufacture of contaminated herbs.
Growing herbs in controlled environments will prevent possible contamination. Organically grown herbs would be the best choice. Good Agricultural and Collection Practices (GACP) guidelines outline the methods for testing of soil, water for contamination and environmental conditions before planting herbs. These guidelines also enumerate the best time and condition for harvesting herbs. By following such guidelines, it is possible to grow herbs that contain the highest quality of bioactive ingredients, which are responsible for the medicinal properties of the herb.
Wrong identification of an herb is a possibility, as most herbs look similar and proper identification of the herb is necessary before its usage in a formulation. Pharmacognostic techniques help in the right identification or establishing the authenticity of the herb. Newer techniques like DNA fingerprinting eliminate the last doubt.
Right dose of herb
Large doses of some vitamins and herbs can be dangerous. The right dose is determined only after meticulous testing on animals and humans for their safety and efficacy. Dosage will be a part of the label on products from reputed manufacturers. Overdosing may result in toxicity.
Herbs are best quantified when used in extract forms. Standardised herb extracts provide reproducible and consistent content of active compounds. Herbs available as standardised extracts produce consistent results and benefits.
Standardisation involves setting values as regards to the quantity of the individual key compounds present in the herb, which have been scientifically proven to be the most advantageous for the human system.
For example, Gotu kola extract with 0.8% active compounds yields superior medicinal value while extracts of milk thistle are standardised to contain 80% active compounds as this level has been shown to provide the greatest natural biological advantage.
Unlike in conventional medicine where the strength and dose do not change, herbs may vary from one batch to another. Standardisation helps in attaining uniformity in dose. Thin layer chromatographic fingerprinting is a sophisticated method used to assess the standardisation, which confirms quality and quantity of herbs in the formula.
Good Manufacturing Practices (GMP)
In order that herbs are of pharmaceutical grade, they have to be manufactured applying modern tools of pharmaceutical technology. It is the manufacturer’s responsibility to see that the supplements they produce are standardised and quality products are produced, which meet the specifications described on the label.
Such manufacturers will have a certification for GMP issued from a competent authority established by the government.
Clinical testing
Despite the fact that many herbs have been used for generations, clinical testing is a must for establishing efficacy and safety. Clinical testing also establishes the right dosing schedule, duration of treatment and long-term safety.
Stability
Herbs are bound to deteriorate with exposure to light, moisture and other environmental factors. To determine the stability of these products, manufacturers need to conduct stability tests on the product and determine the shelf-life. The label should also mention an expiry date and it is advised that such herbs should not be consumed after the expiry date.
Professional advice
One should seek professional advice before consuming an herbal product and it is all the more required while using these products during pregnancy. It is not wise to use herbs without professional advice, as it is not recommended to use herbs during pregnancy unless they are proven safe.
Herbal remedies may sometimes interact with other medicines as well. This makes it particularly important to tell your doctor or pharmacist if you are taking an herbal remedy with other medicines. You should even check with a healthcare professional about long-term consumption of herbs.
Remember that herbal remedies are medicines. As with any other prescription medicine, they are likely to have an effect on the body and should be used with care.
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