British Prime Minister William Gladstone

If you are cold, tea will warm you;

If you are too heated, it will cool you;
If you are depressed, it will cheer you;
If you are excited, it will calm you.

This famous tea quotation is attributed to British Prime Minister William Gladstone (1809–1898) whose public career lasted over sixty years. Gladstone served as PM on four separate occasions and was Britain’s oldest Prime Minister when he resigned for the final time at age 84.

People sometimes ask how tea can have these four unique qualities which seem to be at odds with each other.

How can one beverage both warm and cool, as well as cheer and calm?

The first three attributes are easily understood.

If you are cold, tea will warm you;

Nothing brings more comfort on a cold winter day than a cup of hot tea. Since its introduction into western culture in the mid-17th century, tea has been ever-present to combat the ravages of winter. Throughout Britain, the kettle is often kept steaming from morning until night.

If you are too heated, it will cool you;

I came to understand this firsthand during my first visit to a Darjeeling tea garden. On a sweltering September afternoon, I was invited into the manager’s bungalow on the Castleton Estate for tea. In my home state of Kentucky, the beverage of choice would have been iced tea. On one of the best-known estates in India, we were served steaming hot tea fresh from the garden—with a splash of milk.

One of the behemoth rolling machines at the Castleton Tea Estate in Darjeeling India. (Photo by Bruce Richardson)

The garden manager explained that hot tea helped cool the body because it encouraged the skin to perspire; thus aiding the cooling process. A rotating fan was also pressed into service to aid the body’s air-conditioning.

1950s tea advertisement.

If you are depressed, it will cheer you;

The easy answer here is the presence of caffeine in tea. This stimulant helps keep you alert and awake. Regular tea drinkers swear a cup can counteract a less than cheerful mood.

If you are excited, it will calm you.”

The riddle here is how can a beverage containing the stimulant caffeine calm you?

The answer lies within the amino acid L-theanine, discovered in 1949 in Japan and rarely seen in nature except in tea.

It enhances mood by stimulating alpha brain waves as it subtly balances and moderates the effect of caffeine. The combination of caffeine and L-theanine together make tea unique.

It took the modern invention of the MRI machine to map tea’s effect on the complex workings of the human brain. Doctors at City College of New York investigated this phenomenon in 2006 when they monitored patients’ brain waves as the subjects ingested 250 milligrams of L-theanine. The researchers were able to chart an increase in alpha brainwave activity. This increased alpha rhythm is known to induce a calmer, yet more alert, state of mind.

This modern technological answer to Gladstone’s 19th-century riddle is reassuring to all of us tea drinkers who suspected the outcome for years. We can smile because we knew the answer without the aid of a million dollar machine!