What’s So Hot About Spices?
Besides
their taste, what good are they?
Sour
pork curry from India. Spicy shrimp from Vietnam. Hot tamales
from Mexico. Spicy foods seem to come from countries with
a tropical climate.
Two
scientists, Jennifer Billing and Dr. Paul Sherman, wondered
why. They thought that healthy eating habits probably helped
people survive. But how could eating spicy foods in hot
climates make diners healthier?
Spices come from plant parts: leaves, flowers, fruits, seeds, or roots. (Salt isn’t a true spice since it doesn’t come from a plant.) Chemicals in spice plants have aromas and tastes that people like.
The desire for spices was so great that it affected the course of history. The Phoenicians, Arabs, and Europeans explored the world in search of shortcuts to tropical regions of Asia, where many of the popular spices grew. Christopher Columbus was looking for such a shortcut when he bumped into America.
Without
refrigeration, foods spoil quickly and can cause illness.
Since ancient times, people have used spices to keep food
from spoiling—to preserve it. The Romans used red cumin
and coriander. Pirates preserved wild game for sea travel
by smoking it and rubbing it with allspice. The Egyptians
also knew that spices could prevent decay. They even used
them in mummification.
Strong
Chemicals
Hundreds of years ago people didn’t know how certain
spices preserved foods. Since then, scientists have discovered
that spices contain powerful chemicals. These chemicals
protect the spice plants from bacteria, insects, fungi,
and hungry animals. When we use spices, the same chemicals
prevent the growth of bacteria that spoil our food and can
sometimes make us sick.
Scientists have tested thirty spices on dozens of food-spoiling bacteria. Every spice affected at least one type of bacterium. The super bacteria killers were allspice, garlic, onion, and oregano. These spices killed or slowed the growth of all bacteria on which they were tested.
Some spices aren’t so appealing—at least until you get used to them. You probably wouldn’t cover yourself with the scent of garlic or onion if you were trying to impress your friends. Eating fresh hot peppers and chilies can blister your mouth.
Then why did people start eating foods seasoned with these red-hot spices? Ms. Billing and Dr. Sherman had a clue. The two scientists guessed that people who added the spices to their food would have been healthier than those who didn’t.
If that guess was right, recipes from tropical climates (where foods spoil faster and the risk of food poisoning is higher) should contain more bacteria-killing spices than those from cool climates. To test their idea, the scientists studied recipes in nearly one hundred cookbooks from all over the world.
First they picked traditional dishes that used meat, since meat spoils quickly. They chose older recipes that were first used before refrigeration. Collecting more than 4,500 recipes from thirty-six countries, they listed all the spices used.
The bacteria killers were the big winners! Seven of the world’s ten most commonly used spices have strong antibacterial power: onion, garlic, hot peppers, bay leaf, cinnamon, cloves, and thyme.
Another finding puzzled the scientists. Pepper and lemon/lime juice ranked second and fifth in the Top Ten. This was surprising because these two spices aren’t great at wiping out bacteria. But it turns out that they boost the bacteria-killing power of other spices used with them.
The
Spiciest Dishes
What about climate? Did warmer countries have spicier dishes?
The scientists compared the average temperature of each
country to the number of spices used. They found that dishes
from cooler countries had few spices. (In Scandinavia many
recipes have no spices at all.)
Foods get spicier as the climate gets hotter. Dishes from tropical countries like Ethiopia, India, and Indonesia used the most spices in the world. They had an average of more than six spices per recipe.
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Recipes from hot climates also won the prize for including the most bacteria-killing spices. For example, key ingredients in curry dishes popular in India are cumin, cinnamon, and cloves, all good at killing bacteria or slowing their growth. In the United States, garlic, onion, and hot peppers are used more in the South than they are in the North.
Spices in our food make it more tasty. But as scientists discovered, spices often do an even more important job. People living in hot climates had good reason to get used to strong-tasting spices. These bacteria killers helped preserve foods and kept people healthy.
Today we have other ways to preserve our food, such as refrigerating it and freezing it. But that tasty chili powder might still make your taco a healthier lunch.
