Tea and the effects of tea drinking

by W. Scott Tebb

ANALYSIS OF CHINA TEAS.

(Infusion of 8 grammes with 600 cc of boiling distilled water for 5 minutes.)

No.	Description and District.	Wholesale Price without duty per lb.	Per cent. Extract.	Per cent. Alkaloid.	Per cent. Tannin.	Proportion of tannin corresponding to 2·8 per cent. Alkaloid.
1	Fine Moning, Hankow	1/5	18·80	2·59	3·48	3·76
2	Oolong, Formosa	1/1	24·00	2·46	8·76	9·97
3	Souchong	--	18·30	2·60	2·44	2·63
4	Moning	1/1	20·43	2·23	2·96	3·71
5	Scented Orange Pekoe Canton	1/2	23·81	2·68	7·70	8·04
6	Gunpowder, Green Tea	1/4	29·47	2·55	9·54	10·47
7	Caper, Green Tea	10³⁄₄d.	21·45	1·87	9·08	13·59
8	Oolong	10d.	23·62	2·47	8·80	9·97
9	Hyson, Green Tea	1/4	26·81	2·32	9·62	11·61
10	Pakling	5¹⁄₄d.	18·77	1·81	3·19	4·93
11	Pekoe Souchong, Lapsang	1/5	19·31	2·36	2·33	2·76
12	Panyang	4¹⁄₂d.	21·00	1·93	4·71	6·83
13	New make	8¹⁄₂d.	21·78	3·40	6·42	5·28

The last column in the above tables or the proportional amount of tannin is arrived at in the following manner. I first calculate the average amount of alkaloid in tea as consumed on a basis of the above figures. Thus the average amount of alkaloid in Indian teas as seen in Table H calculates out to 2·84 per cent. This is multiplied by the proportion of Indian teas on the market, viz. about 60 per cent. in the same way the average Ceylon alkaloid 2·68 is multiplied by 30, and the China average 2·40 multiplied by 6. If we add these products together and divide by 60 + 30 + 6 = 96 this will give us the average percentage of alkaloid in tea as consumed and this amounts to about 2·8 per cent. The last column in Tables E, F and G, gives the proportion of tannin corresponding to 2·8 per cent. alkaloid; that is to say the tannin in each case is multiplied by 2·8 and divided by the amount of alkaloid actually present. This figure which represents the proportional amount of tannin present renders the comparison of the different teas possible so far as the astringent action is concerned.

The following table summarises the results of analyses of the three classes of teas:—

Table H.

Class of Teas.	Number of Analyses.	Per cent. Extract.	Per cent. Alkaloid.	Per cent. Tannin.	Proportion of tannin corresponding to 2·8 per cent. Alkaloid.
Indian Teas	18	26·11	2·84	7·43	7·32
Ceylon Teas	12	26·04	2·68	7·85	8·20
China Teas	13	22·12	2·40	6·08	7·09

Thus the Ceylon teas under the conditions of experiment part with slightly more tannin than the India or China teas. It will be noticed that the proportional tannin figures for the India and China teas are not very different, although some of the individual China teas give out less tannin than any of the India or Ceylon samples. It is possible that the China average is rendered rather high by an undue proportion of green tea which of course shows excess of tannin. The question will naturally be asked whether as a nation we do not drink too much tea, and there is a very simple means of solving the problem. As shown in table A the average consumption per head per annum in the United Kingdom is 6·1 pounds, or 117 grains of tea per diem. The average percentage of alkaloid in tea, as consumed, I calculate to be 2·8 per cent., and of tannin 7·5 per cent. This will mean that each person will take a daily dose of 3·28 grains of alkaloid and 8·8 grains of tannin. According to the last Census 3,716,708 out of 32,527,843, or 10 per cent. of the population of England and Wales, are under five years of age; these might almost be neglected as far as tea-drinking is concerned, so that we must add one-tenth to the average daily dose of the alkaloid and tannin, which will come to 3·6 grains of alkaloid, and 9·7 grains of tannin. The dose of caffeine according to the British Pharmacopœia is from one to five grains and of tannin from two to five grains. And hence on an average each person in the United Kingdom is constantly day by day consuming half as much alkaloid, and nearly as much tannin as would be permissible to be taken occasionally as a drug. Therefore I have no hesitation whatever in saying that we drink far too much tea, and the question has been raised in Ireland whether the excessive drinking of strongly infused tea has not had something to do with the increasing prevalence of insanity in that country. Thus in the Forty-third Annual Report of the Inspectors of Lunatics, Ireland (1894), the Inspectors dwell on the ill effects of decocted or over infused tea on persons who make it a staple article of dietary, thus leading to the production of dyspepsia, which in its turn tends to states of mental depression highly favourable to the production of the various forms of neurotic disturbance.

Thus Dr. William Graham of the Armagh District Asylum refers to the recent changes of dietary having an unquestioned influence on the increasing prevalence of insanity. He refers to the use of Indian tea as a beverage between meals. “The tea,” he says, “is stewed, not infused, as a consequence the use of increased amount of nervine food leads to a peculiar form of dyspepsia, which in its turn leads to a general debility of the nervous system. This change is therefore to be considered as a factor in the increase of insanity.” Dr. G. W. Hatchell, the Resident Medical Superintendent of the Castlebar District Asylum, stated that “amongst the female inmates, I believe many cases of insanity may be attributable to the frequent consumption of decoction of tea, taken generally without food and for lengthened periods.”

Again Dr. Thomas Drapes of the Enniscorthy Asylum, said “there is not much evidence of the excessive use of this beverage (tea) being directly provocative of insanity, but I think there is very little doubt that its too liberal use excites or aggravates a predisposition to neurotic disorders, including insanity, making the nervous system more vulnerable in regard to such maladies, by the increased excitability of the nervous system which tea undoubtedly produces. A neurotic organisation may also be transmitted to their progeny by parents who drink tea to excess.”