Any world traveler can attest to the pungent truth: Spicy meals tend to be found in warmer climates, while blander foods correlate to colder places. For years, people believed spices were used in the countries where they were grown to mask the taste of spoiled meat or solely for the flavor they add to food.
Alas, nothing in nature turns out to be that simple. Researchers now suggest that a taste for spices served a vital evolutionary purpose: keeping our ancestors alive. Spices, it turns out, can kill poisonous bacteria and fungi that may contaminate our food. In other words, developing a taste for these spices could be good for our health. And since food spoils more quickly in hotter weather, it's only natural that warmer climates have more bacteria-killing spices.
Indeed, the very plants that produce spices use them in this way. Spices that come from shrubs, vines, trees, and the roots, flowers, and seeds of plants protect the vegetation against the same bacteria and fungi that attack our food when we've left it overnight on the kitchen counter. Before refrigeration, food spoilage was an even more pressing problem, which is why some researchers say spices played such a huge role in history -- one Gothic leader in A.D. 408 demanded 3,000 pounds of pepper as ransom. And adventurers from Marco Polo to Christopher Columbus sailed the world mapping routes to spice-growing countries.
More recently, a team of biologists at Cornell University in New York debunked most popular beliefs about spices, including the idea that they're used to make people sweat in order to cool them down. But one popular belief still stood: Spices seem to help with food digestion, and, for some unknown reason, people in warmer climates might need more help.
The Cornell scientists tested the bacteria-killer hypothesis with hundreds of cookbooks and thousands of recipes from around the world. They discovered that spices with the greatest ability to kill bacteria, such as garlic and onions, appear most often -- and in greater concentrations -- in recipes from hot climates. Eighty percent of Indian recipes called for onions, while in Norway, the pungent bulb only appeared in 20 percent of the recipes. They even found these differences within the United States. For example, we have spicy Cajun meals down south and more bland meat staples in northern Maine.
Although not everyone is convinced yet that the evidence is conclusive, the idea that our ancestors' taste for spice might be something that natural selection favored in certain environments is an intriguing one.