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Tobacco and Cancer Programme International Union Against Cancer 3, Rue du Conseil-Général, 1205 Geneva, Switzerland Tel: (4122) 809 1830, Fax: (4122) 809 1810 E-mail: tobacco-control@globalink.org | Tobacco and Cancer Programme |
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Introduction
Areca nut chewing is a practice of great antiquity in many parts of Asia and in some Pacific islands. In India this practice is at least 2000 years old; it is an integral part of the religious and cultural rituals and also of everyday life. In the medical as well as popular literature it has often been referred to, rather erroneously, as betel nut.
Description
The areca nut is the fruit of the tree Areca catechu, a palm with a tall slender stem crowned by a tuft of large, elegant leaves. The fruit, which is orange-yellow in colour when ripe, grows in large bunches at the base of the leaves. The seed (endosperm) is separated from the fibrous pericarp and can be used fresh, after sun drying, curing or baking. Curing is done by boiling the seed in water with a little extract from previous years' curing; this results in uniform colour, softens the nut, and reduces the tannin content.
The two most important constituents of areca nut are tannins (11-26%) and alkaloids (0.15-0.67%). Arecoline is the major alkaloid. Some of the minor ones are arecaidine, guacine, guvacoline and arecolidine. Other constituents of areca nut include fats, carbohydrates, proteins, and various other substances.
Methods of use
Areca nut is most commonly chewed as a constituent of betel quid. The betel quid is a mixture of betel leaf, areca nut, and slaked lime (calcium hydroxide). Depending upon individual and local preferences, condiments, sweetening agents, and spices may be added. In India, most habitual chewers of betel quid add tobacco. In some countries, e.g., Papua New Guinea, tobacco is not added.
Areca nut can also be chewed without any other ingredients. A wide variety of areca nut preparations can be bought from the market: uncured, cured, whole, broken, wafered, shredded, commercially manufactured, etc. Expensive varieties are finely cut, sweetened and flavoured with condiments and spices such as cardamom, clove, saffron, cinnamon, and decorated with silver foils. In the north-eastern part of India (Assam), the use of fermented areca nut (tamol) is common. It contains higher levels of arecoline and is often infected with fungus.
There are many ways of chewing areca nut with other substances. Mainpuri tobacco is a mixture of areca nut, tobacco, lime, and condiments. It is popular in part of northern India and is highly carcinogenic. Mawa is a mixture of about 5 g areca nut pieces and 0.5 g tobacco sprinkled with a few drops of lime (calcium hydroxide) water. It shows a high relative risk for oral submucous fibrosis. Gutka is the name given to the mixture that is put in betel-quid except that it is not wrapped in betel leaf.
In recent years an increasingly popular form of areca nut chewing is the use of so-called "betel quid spices" (Pan Masala). These are commercially manufactured, marketed and advertised on a large scale. They are available in tins and foil packets. Their main appeal perhaps lies in the fact that unlike betel quid they are not perishable.
Prevalence
The use of areca nut is widely prevalent in India, Pakistan, Bangladesh, Sri Lanka and Papua New Guinea, and its use is also reported from parts of Indonesia, Myanmar (Burma), Cambodia, Vietnam, Philippines, Taiwan, South China, and several islands in the Pacific Ocean. This practice has been carried over by the emigrant communities from South-Asia to several Western and African countries. It is estimated that currently there are several hundred million users of areca nut in the world. Population-based prevalence figures are available from India; they vary widely in different areas. The prevalence is high in south India. In Ernakulam district, for example, over a third of the population 15 years and older was reported to use areca nut regularly, generally in the form of betel quid with tobacco.
Health effects
It has now been established that areca nut use causes oral submucous fibrosis which is a serious debilitating and progressive disease. This disease is marked by stiffening of the oral mucosa and development of fibrous bands resulting in a restricted mouth opening. Submucous fibrosis is not reversible nor is there any effective cure. The most serious aspect of this disease is its precancerous nature. The risk of developing oral cancer among individuals with oral sub-mucous fibrosis has been demonstrated to be very high, especially if they also use tobacco, whether in smokeless or smoking form.
Since most individuals who use areca nut also use tobacco either in the form of chewing or smoking, the epidemiological evidence about the carcinogenicity of areca nut alone has not been regarded as sufficient.
There is some experimental evidence. For example, it has been shown that in the presence of salivary nitrates, areca nut alkaloids can form nitrosamines that are carcinogenic. There are case reports of oral cancer developing among individuals who use areca nut but do not use tobacco in any form.
Conclusion
Although chewing of areca nut may be a practice of great antiquity, it cannot be regarded as a safe habit. As a practice that is often associated with concurrent smokeless tobacco use, it needs to be strongly discouraged.
Acknowledgement
This fact sheet has been prepared for the UICC by Pradesh C. Gupta, D.Sc., F.A.C.E., Senior Research Scientist, Tata Institute of Fundamental Research, Bombay, India.
References
2/1996
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Tobacco and Cancer Programme International Union Against Cancer 3, Rue du Conseil-Général, 1205 Geneva, Switzerland Tel: (4122) 809 1830, Fax: (4122) 809 1810 E-mail: tobacco-control@globalink.org | Tobacco and Cancer Programme |
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