Tea and the effects of tea drinking

by W. Scott Tebb

I suppose that this verse has been as much quoted as anything in our language, and the homely picture of the evening meal has done much to wean the English people from stronger drinks.

The following article from the Lancet of 1863 presents all the arguments, and very important arguments they are and very well stated which can be placed to the credit of tea-drinking:—

“It has a strange influence over mood—a strange power of changing the look of things, and changing it for the better: so that we can believe and hope, and do under the influence of tea, what we should otherwise give up in discouragement and despair,—feelings under the influence of which tissues wear rapidly. In the language of the poor, who in London we are told spend one-eight of their income in buying tea, it produces a feeling of comfort. Neither the philosopher nor the philanthropist will despise this property of tea, this power of conferring comfort, or removing ennui, of promoting those happier feelings of our nature under which we can do most and bear most. There is no denying the considerable dependence of our moods and frames upon substances; and as moods are as important as muscles, as they affect as largely a man’s ability for the great ends of life, we cannot regard the cheapening of such substances, when devoid of noxious qualities, as other than a most important benefit to the poor.”

This feeling of comfort, this power of changing the aspect of affairs, of appealing to the happier side of our nature, in other words of putting us at our best, is undoubtedly due to the alkaloid of tea. Since I have been interested in the subject I have conversed with a number of friends, and many have told me that the best time of day to do any writing or intellectual work is after a cup of tea in the afternoon, and I must confess to feeling more myself at this time than at any other; but, on the other hand if no afternoon tea is taken, this period of the day is when most people feel fagged and tired and incapable of mental exertion. This shews the great influence exercised by tea over our moods and feelings; and if tea is taken in moderation this property may be of great help and a mental stimulus to us in our daily vocation.

Tannin.—The other important constituent of tea, viz.: tannin is present to the extent of 10 or 20 per cent. and it is this substance to which most of the injurious effects of tea have been attributed. In excess tannin tends to depress the action of the digestive fluids and ferments. It interferes with the normal activity of secretion by constricting the blood vessels and diminishing the circulation, and lastly it tends to combine with the nitrogenous principles of the food rendering them insoluble and incapable of digestion. The tendency therefore of this substance is greatly to impair digestion and it gives rise to palpitation of the heart, headache, flatulence, loss of appetite, constipation and other symptoms so well-known at the out-patient departments of our general hospitals; on inquiry it is often found that the patient is accustomed to drink large quantities of tea, which has stood for long periods and consequently extracted excessive amounts of tannin.

In addition to the alkaloid and tannin the older writers asserted that tea contained a volatile oil to the extent of 0·6 to 1 per cent., and many of the qualities and deleterious effects of tea have been traced to the presence of this substance. The latest experiments, however throw some doubts on these early results. Thus in the report of Schimmel & Co. for April, 1897, it is stated (p. 39) that “in former years we endeavoured on several occasions to distil various kinds of tea in order to introduce tea oil ... we have, however, in no case succeeded in obtaining more than mere traces of oil,” and they conclude that in the hands of the early experimenters the oil found on distillation was due to the artificial flavouring of tea which was common at that time. Schimmel & Co. in their Report for April, 1898 (p. 50) refer to a report of the Botanical Gardens in Buitenzorg for 1896. It appears that experiments were made on a large scale, thus 2500 kilograms of freshly fermented tea leaves were submitted to steam distillation and 130 cubic centimetres or 0·0052 per cent. of oil was obtained.[10] It must be remembered that this oil was only found in freshly fermented leaves and from the minute quantity I think we may conclude that tea oil if present has little or no connection with the qualities and attributes of tea, or the deleterious effects to which it may give rise.

A word or two with reference to the adulteration of tea. In former times a good many samples and especially of green tea were faced; this consisted in the addition of some colouring matter as Prussian blue, turmeric, or indigo; and sometimes black tea was faced with graphite. Another practice formerly prevalent was the addition of various leaves having a resemblance to tea leaves; and then there was the use of exhausted or spent leaves. All these forms of adulteration are now happily very seldom practiced. To shew the extreme rarity of tea adulteration in this country, in the 17 years from 1887 to 1903, 7595 samples were purchased under the Food and Drugs Acts and of these only 23 were found to be adulterated. These figures include 15 cases in 1898, and according to the report of the Local Government Board for this year many were of the description known as caper tea. This is one of the China varieties and consists of small granular masses made up by the aid of gum and starch, and this lends itself to the addition of sand and stones as actually happened in the cases in question. I think that with this exception of mineral matter, tea adulteration in this country may now be said to be practically non-existant.

We have glanced through the general effects of the important constituents of tea. I now propose to consider the amount of harm which can be justly attributed to this popular article of daily consumption.

The opposition to tea on the ground of injury to health is almost as old as the introduction of tea itself. One of the earliest objectors was Dr. Simon Pauli,[11] the Physician to the King of Denmark, in a commentary he wrote on the abuse of tobacco and tea. He objected on the ground that “tea is moderately heating, bitter, drying and astringent.” He felt it incumbent on him to warn Europeans against the abuse of tea, especially as the herb he said by no means answered the encomiums bestowed upon it by the Chinese and Japanese. “I wish all persons especially such as are old would obstinately reject tea, which so dries the bodies of the Chinese that they can hardly spit.” Pauli was also a strong opponent of Coffee and alleged that it produced “sterility.”

Another powerful writer on the subject was Dr. Cohausen a learned and ingenious German physician. The works of this author were numerous and bore evidence of the vigour of his intellect and of his application to letters. His work entitled “Neothea,” and published in 1716, was written to shew the folly of sending to China for tea, when we had so many herbs to hand, just as pleasant and far more healthy. His wit for which he was justly celebrated was not sufficiently powerful to render the use of tea unfashionable.