Citrus

Twenty-five millions years ago, when the Indian subcontinent collided into the Eurasian plate to seal the remaining Tethys Ocean gap while thrusting the Himalayas skyward, began the spread of the citrus genus to East Asia.  Its cultivation first expanded eastward into Micronesia and Polynesia by Austronesian voyagers between 3000 and 1500 BC.  It traveled westward by Persia and the southern Levant, where remains were found in a Persian royal garden near Jerusalem dated to the 5th and 4th centuries BC.  From there it arrived in the Mediterranean through Alexander the Great’s conquests around 330 BC.  Today the citrus has evolved into a plethora of varieties and hybridizations, even more so than those of apples and grapes.

The citrus is first and foremost prized for its smell.  The word citrus comes from the Latin word “citrum”, the timber of a Mediterranean cypress used to scent rooms and clothes.  The word “citrum” in turn may come from the word “cedrus”, the Greek name for the aromatic juniper.  Citrus flowers and peels are extracted into aromatic waters and oils to perfume people and food alike.  Of the exotic varieties, yuzu and bergamot are most prized for their fragrance, yuzu in East Asia, and the later in the Mediterranean.  The name bergamot is derived from the fruit’s resemblance to the bergamot pear, whose name came from the Turkish “beg-armudi”, or “the prince’s pear.”  It gives Earl Grey tea its distinctive flavor – not especially citrusy, but more reminiscent of lavender flowers.  Most of the world’s supply of bergamot is cultivated in the southern Italian region of Calabria.

Another compound held in abundance in citrus fruits, particularly in lemon, is ascorbic acid, or vitamin C, an essential antioxidant to keep the human body healthy.  Because vitamin C quickly breaks down in the presence of light, heat, and air, it is only available in fresh produce.  Without vitamin C, our body eventually develops scurvy, a terrible disease beginning with swollen gums and loose teeth and ending with swollen, blackened legs and arms and death.  The 13th-century Andalusian scholar Abu Abdallah described this painful disease in his poem Scurvy Entertainment:
Abdul Aziz one day
Invited me to stay:
May Allah, if He please,
Not bless Abdul Aziz!

He poured me wine, the which
Was black as bubbling pitch,
And served (this really hurt!)
Goats’ horns for my dessert.

Then came a foul old hag
And offered me a bag
Of raisins, each a mole
Plucked from her withered jowl!*

As our body can’t synthesize the vitamin, it has become very efficient at conserving it.  It takes up to six months to see vitamin C deficiency, which is why the disease was a leading killer among sailors on long ocean voyages.  The poet Luís de Camões described the torment afflicted by this illness in The Lusiad, or The Discovery of India, which celebrated the Portuguese explorer Vasco da Gama’s adventures in forging a path to India:
“A dread disease its rankling horrors shed,
And death’s dire ravage through mine army spread.
Never mine eyes such dreary sight beheld,
Ghastly the mouth and gums enormous swell’d;
And instant, putrid like a dead man’s wound,
Poisoned with fœtid steams the air around.
No sage physician’s ever-watchful zeal,
No skilful surgeon’s gentle hand to heal,
Were found: each dreary mournful hour we gave
Some brave companion to a foreign grave.”

It has been known since antiquity that fresh fruits, in particular lemons and oranges, cure scurvy.  Beginning with Vasco da Gama’s explorations in 1497, sailors had become aware of lemon juice’s ability to cure scurvy, yet this knowledge was often forgotten, then having to be relearned by subsequent explorers.  By the early 19th century, the Royal Navy’s daily serving of lemon juice with sugar to their sailors allowed British ships to stay on blockade duty for two years at a time while scurvy remained a deadly challenge for other navies.  By the middle of the 19th century however, advances in steam power technologies meant shorter travels over sea, rendering daily supplementation of lemon juice unnecessary.  By 1860, lemon juice was replaced with West Indian lime juice, which, unbeknownst to them, had a quarter of the scurvy-fighting power of fresh lemon juice, but it took a while for anyone to notice.

By 1875, scurvy once again threatened lives, even among those taking daily doses of lime juice while on the Arctic expedition into the North Pole led by George Nares. During the Jackson-Harmsworth expedition to Franz-Josef Land in 1894, which lasted 3 years on pack ice, their chief physician Koettlitz wrote, “The expedition proper ate fresh meat regularly at least once a day in the shape of polar bear. The people on the ship had, however, a prejudice against this food, which certainly was not particularly palatable, and insisted, against all advice, upon eating their preserved and salted meat. …. The result was that, though I visited the ship every day, and personally saw that each man swallowed his dose of lime juice (which was made compulsory, and was of the best quality), the whole ship’s company were tainted with scurvy, and two died.”  This consistent observation that consumption of fresh meat prevented scurvy in the Arctic defied the common understanding of scurvy as a lack in vegetable consumption.

It would not be until 1932 that the Hungarian biochemist Albert Szent-Györgyi finally isolated ascorbic acid as the compound to fend off scurvy, that it was a deficiency disease and not a condition of vital humors, bad air, acidification of the blood, or bacterial infection as physicians of each corresponding era had insisted.  Today we know that vitamin C not only resides in lemon, but can also be found plentiful in fresh meat, particularly in the raw liver of bear, considered a delicacy of the Arctic. 

*Translated by A. J. Arberry.