The history (and health claims) of the tea

How do you take your tea – with a drop of poisonous chemicals or a spoonful of sheep dung? Throughout history, the health benefits – and harms – of this popular beverage have been widely debated. In an article originally published in the student science magazine BlueSci, Sophie Protheroe, an undergraduate student at Murray Edwards College, examines the global history of tea and its effect on our health.

Nothing says Britain quite like a cup of tea. As a nation, we have been drinking it for over 350 years. But tea has endured a tumultuous journey to reach its status as the nation's favourite beverage.

Originating in China, where it was thought to have medicinal properties, tea's history is closely intertwined with the history of botany and herbal medicine. Legend states that the very first cup of tea was drunk in 2737BC by the Chinese emperor Shennong, believed to be the creator of Chinese medicine. Shennong was resting under the shade of a Camellia sinensis tree, boiling water to drink when dried leaves from the tree floated into the water pot, changing the water's colour. Shennong tried the infusion and was pleased by its flavour and restorative properties.

A more gruesome Indian legend attributes the discovery of tea to the Buddha. During a pilgrimage to China, he vowed to meditate non-stop for nine years but inevitably fell asleep. Outraged by his weakness, he cut off his own eyelids and threw them to the ground. Where they fell, a tree with eyelid-shaped leaves took root: the first tea tree.

Regardless of the truth behind the legends, tea has played a pivotal role in Asian culture for centuries. The earliest known treatise on tea is 'Ch'a Ching' or 'The Classic of Tea,' written by the Chinese writer Lu Yu. The book describes the mythological origins of tea, as well as its horticultural and medicinal properties, and contains prolific instructions on the practice and etiquette of making tea. This was considered a highly valued skill in China and to be unable to make tea well and with elegance was deemed a disgrace.

Tea was thought of as a medicinal drink until the late sixth century. During the T'ang dynasty between the seventh to tenth centuries, tea drinking was particularly popular. Different preparations emerged, with increasing oxidation producing darker teas ranging from white to green to black. Other plant substances were added, including onion, ginger, orange or peppermint with different infusions believed to have unique medicinal properties. Over time, tea was no longer restricted to medicinal use and was also generally consumed as a beverage.

Tea came to Europe in the late sixteenth century during the Age of Discovery, a time of extensive overseas exploration. Natural philosophers discovered many new plants which they collected and used for medicines or for general consumption. Of particular interest were plants with stimulant properties, such as team coffee, chocolate, tobacco and ginseng. Europeans learned of the medicinal uses of plants from local people. However, Asians remained sceptical that the healing properties of tea would have any effect on the health of Europeans, claiming that the medicinal value was unique to Asians.

Portuguese merchants were the first to bring home tea (known to them as 'Cha,' from the Cantonese slang) from their travels in China. However, the Dutch were the first to commercially import tea, which quickly became fashionable across Europe. Tea came to Britain in the 17th century and its popularity stems from Catherine of Braganza, a Portuguese princess and tea addict, the wife of Charles II. Her love of tea made it fashionable both at court and amongst the wealthy classes. Due to high taxes, tea remained a drink of the wealthy for many years. In the 18th century, an organised crime network of tea smuggling and adulteration emerged. Leaves from other plants were used in the place of tea leaves and a convincing colour was achieved by adding substances ranging from poisonous copper carbonate to sheep's dung.

When tea was introduced to Britain, it was advertised as a medicine. Thomas Garraway, owner of Garraway's coffee house in London, claimed that tea would, "maketh the body active and lusty" but also "…removeth the obstructions of the spleen…" and that it was "very good against the Stone and Gravel, cleaning the Kidneys and Uriters". The Dutch doctor Cornelius Decker, profusely prescribed the consumption of tea, recommending eight to ten cups per day and claiming to drink 50 to 100 cups daily himself. Samuel Johnson was yet another doctor known to indulge in excessive tea drinking, rumoured to have consumed as many as sixteen cups at one tea party, and was an avid defender of the health benefits of tea. In 1730, Thomas Short performed many experiments on the health effects of tea and published the results, claiming that it had curative properties against ailments such as scurvy, indigestion, chronic fear and grief.

However, the health effects of tea were debated and by the mid-18th century accusations that tea was detrimental to health were brewing. Wealthy philanthropists worried that excessive tea drinking amongst the working classes would cause weakness and melancholy. One French doctor warned that overconsumption of tea would result in excess heat within the body, leading to sickness and death. John Wesley, an Anglican minister, condemned tea due to its stimulant properties, stating that it was harmful to the body and soul, leading to numerous nervous disorders. Wesley even offered advice on how to deal with the awkward situation of having to refuse an offered cup of tea.

The English traveller Jonas Hanway believed that tea-drinking was a risk to the nation, leading to declining health of the workforce. He was particularly concerned about the effect on women, warning that it made them less beautiful. Arthur Young, a political economist, objected to tea because of the time lost to tea breaks. He criticised the fact that some members of the working class would drink tea instead of eating a hot meal at midday, reducing their nutritional intake: tea replaced the traditionally working class drink of home brewed beer, which had a higher nutritional value than tea; tea contains no calories without milk or sugar. Thomas Short, a Scottish doctor, claimed that tea caused disastrous ailments and argued that people would spend money on tea over food. In reality, the working class often bought very cheap grades of tea or once-used tea leaves from wealthier families.

Eventually, tea regained popularity as philanthropists realised the value of tea drinking in the temperance movement, offering tea as a substitute for alcohol. During the 1830s, many coffee houses and cafes opened as alternatives to pubs and inns, and from the 1880s, tea rooms and tea shops became popular and fashionable.

Today, tea remains the most widely consumed beverage in the world. It has been estimated that tea accounts for 40% of the daily fluid intake of the British public. So, is this lavish consumption affecting our health? A study at Harvard University Medical School suggests that tea may have health benefits; tea contains polyphenols, which are especially prevalent in green tea, and have anti-inflammatory and anti-oxidant properties which could prevent damage caused by elevated levels of oxidants, including damage to artery walls which can contribute to cardiovascular disease. However, these effects have not been directly studied in humans and it may be that tea drinkers simply live healthier lives. However, to date there is no conclusive evidence suggesting tea has any genuine effects on health, either positive or negative.

It seems that the controversies surrounding the medicinal use of tea may be little more than a storm in a teacup.