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| Thursday, 1 April 2004 |
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Some health aspects of tea production and consumption by Rohan H. Wickramasinghe, Institute for Tropical Environment Studies In recent years, the public is increasingly paying attention to the health of workers engaged in the production of tea both in Sri Lanka and elsewhere and also to the health effects of the drinking of tea. The following account gives an insight to certain issues in these areas although much remains to be done. Support by the government and relevant trade unions for further research in these and related areas is very desirable. Occupational Health In the early years of the tea industry, the entrepreneurs were opening up a new field, both literally and figuratively speaking, and occupational health problems took time to be identified. Medical science and scientific techniques were, also, far less advanced than they are now so the instruments by which problems could be investigated, elucidated and cured were not available either. Some areas to which attention has been drawn in the course of the last century are as follows: * Tea Factory Cough: A Castellani and A. J. Chalmers (1919) working in Sri Lanka described a condition where workers in tea factories developed loss of weight, tiredness and a cough. The symptoms disappeared gradually if these factory workers were sent to work in the field. * Tea Tasters' Disease - Castellani and Chalmers (1919) also described a condition they termed 'Tea tasters' disease'. This arose since tea tasters not only tasted the infusions but also buried their noses in the tea leaves. The tea dust found with the leaves contains fungi such as Monilia, Aspergillus and Penicillium and also an unusual Streptococcus. The symptoms, which resemble those of platinum asthma, disappear about thirty minutes after the worker leaves the factory premises. * Tea Tasters' Asthma: Uragoda (1970, 1992) observed that tea makers (who supervise the manufacture of tea in the factory) develop asthma following inhalation of the fine dust called 'tea fluff'. This is a different condition from the two described earlier. * Chronic Bronchitis: Following a study of 125 persons engaged in the blending of tea, Uragoda (1980, 1992) reported that the incident of chronic bronchitis was higher than that observed in the general population. * Pulmonary Tuberculosis: The incidence of active or inactive pulmonary tuberculosis among workers in the above study (Uragoda 1980) was found not to be significantly different from that in the general population. * Investigations on the Health of Tea Pluckers: Investigations have so far mainly focused on the health of those engaged with tea manufacture and subsequent operations. Studies on those concerned with tea plucking would be desirable (Modder 1999). Tea and Health Health Maintenance The constituents and nutritional components of tea have been the subject of frequent study. Caffeine was discovered in tea by Oudry in 1827; though it was called 'thein' by him at the time. Theobromine and theophylline have actions resembling those of caffeine. Black tea contains, among others, calories (2 calories per rounded teaspoonsful), proteins (22 per cent by dry weight of which less than 2 per cent is soluble), free amino acids (a small amount of which declines on keeping possibly due to reaction with tea polyphenols), carbohydrates (4 - 5 per cent of the solids extracted by hot water which, however, dissolves only a small amount of the pectins and pectosans present, carbohydrates constitute around 31 per cent of the dry weight of unprocessed tea) and lipids (phospholipids, gylcolipids, sulpholipids, triglycerides, saponins, glycosylated and esterified steroids and terpenoids to 2 - 3 per cent by weight). The inorganic matter content of black tea is 4 - 9 per cent and contains most of the minerals (including magnesium, potassium, copper, iron and flourine but little sodium) required for good health although contents may vary depending on the soil, age of the leaf etc. Vitamins present in black tea include vitamin B (riboflavin, niacin, pantothenic acid, inositol, thiamine, folic acid and biotin), vitamin E (tocopherol) and vitamin K (phylloquinone), Pro-vitamin A (carotene) and vitamin C occur in significant amounts in unprocessed tea. Interest has been shown in investigating the possibility of the benefit of tea drinking or of the use of one or more constituents a) to prevent cancer, b) to prevent atherosclerosis, c) against food-borne, cariogenic or phytopathogenic bacteria, d) as a protection against Vibrio cholerate, e) against Clostridium botulinum toxin. f) to suppress increase of cholesterol and fat, g) to inhibit angiotensin I converting enzyme, h) as a radiation protection agent, j) as an agent against ulcers and against mutagenesis etc. Further investigations of these and similar possibilities will continue to be made. It may also be kept in mind that the regular ingestion of tea may help to pre-condition the functions of the body in ways, for instance, that will render it less vulnerable to certain ailments or more receptive to certain medicaments, as has been proposed in respect of the consumption of spices (Wickramasinghe, Mueller and Norpoth 1980). Medicinal Value Caffeine has a weak stimulatory effect. Quercetin, the depsides and 3-flavonols, such as ellegic acid and (-) epigallocatechin gallate, are said to posses anti-cancer properties. The latter is also a strong inhibitor of the aggregation of the platelets of the blood. Investigations are also made on the efficacy of tea or of one of more of its constituents a) to reduce blood glocuse levels, b) to suppress hypertension and strokes, c) against influenza virus, d) against halitosis, e) against allergies etc. Further investigations will continue to be made of these and similar possibilities of devising new and safe medications. |
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