Wonder-food

Feb 28th 2008
From The Economist print edition

ON THE face of it, John Reader's new biography of the potato seems to have a silly title—“propitious esculent” is just a fancy way to say “helpful food”—and an even sillier subtitle. But that is because the virtues of the world's fourth biggest food crop (after maize, wheat and rice) and its influence on world history are easily overlooked. “I used to take potatoes for granted,” the author writes. His aim is to discourage readers from doing likewise.

The key to the potato's value lies in its high yield and its almost perfect balance of nutrients. Potatoes can produce more energy per unit area per day than any other crop, and it is possible (though tedious) to subsist on a diet of spuds and very little else.

First domesticated in the Andes, the potato was carried to Europe in the 16th century. At first Europeans were suspicious: the potato was variously thought to be an aphrodisiac, to cause leprosy or to be poisonous. But it slowly caught on as its merits in times of famine and war became apparent (it is more reliable than grain and remains hidden underground until harvested). By the late 18th century it was being hailed as a wonder-food—for the poor, at least. Marie Antoinette promoted potatoes by wearing their flowers in her hair.

People then started to worry that the potato was too popular, and that its abundance was causing an unsustainable increase in population. Exhibit A was Ireland, where the booming population subsisted almost entirely on potatoes. The danger of such dependency was starkly revealed by the Irish potato famine of 1845: at least a million people died, and another million emigrated.

Mr Reader's tale ends with the modern efforts to understand the genetics of the potato, which could lead to more disease-resistant varieties. The propitious esculent, he explains, is likely to feature in the diets of space-farers who will have to grow their own food.

The all-potato diet will not appeal to all readers, but this accessible account embraces the latest scholarship and addresses the failings of previous works on the subject. Indeed the book, like the tuber it describes, fills a void: the spud now has the biography it deserves.