About five years ago, reports surfaced of an East Indian chile pepper that was trumpeted as the hottest in the world - twice as hot as the Red Savina pepper, which held the Guinness title at the time.
This intrigued Paul Bosland, director of the Chile Pepper Institute at New Mexico State University. He noted that no one had verified how hot this little chile pepper really was - and decided to find out for himself.
In 2001, Bosland managed to obtain seeds of the mystery pepper from a colleague who had recently returned from India. It took four years to grow enough peppers for testing, but Bosland's efforts paid off. In 2005, his lab confirmed that the Bhut Jolokia pepper did, indeed, have the highest heat ever recorded. This past February, Bhut Jolokia was crowned by Guinness as the "hottest of all spices."
The chemical that gives peppers their bite, capsaicin, is found only in chile peppers. Interestingly, birds cannot detect the chemical, a tweak of evolution that helps ensure the pepper's survival. If the pepper's seeds are consumed by mammals, they are crushed and rendered infertile. But because of their bite, most mammals avoid them.
Birds, on the other hand, readily eat peppers. And, unlike mammals, they release the seeds from their digestive tracts intact - conveniently packaged with a dose of natural fertilizer.
The most well-known work on capsaicin was done in the early 1900s by Wilbur Scoville, a chemist who developed the Scoville scale, a measure still in use today that expresses the heat in peppers.
Bell peppers contain no capsaicin and have a zero rating on the Scoville scale.
Jalapenos come in at about 5,000 Scoville Heat Units, habaneros at about 300,000.
But these pale in comparison to the Bhut Jolokia - which has a confirmed Scoville rating of more than a million units.
For many of us, the heat of the pepper is what makes it such a palate pleaser. But peppers also have a lot going for them nutritionally - they are good sources of vitamin C, beta carotene, folic acid, magnesium and potassium. Peppers and capsaicin also have anti-inflammatory and antioxidant effects, which might reduce the risk of heart disease, certain cancers and other chronic diseases that occur with age.
Chile-laden meals have been shown to boost energy expenditure in several human trials. In one study, for instance, 10 grams of dried hot pepper added to breakfast increased energy expenditure by 23 percent immediately after the meal and for more than two hours afterward.
And a study published last year in the British Journal of Nutrition showed that regular chile consumption interferes with a step in the development and progression of atherosclerosis: the oxidation of lipoproteins in the blood.
It's a common notion that eating hot chile peppers might irritate the stomach or even lead to stomach ulcers. In fact, the opposite appears to be true. Rather than causing an increase in stomach acid production, capsaicin inhibits acid secretion and stimulates alkaline mucus secretions. This may actually help in the prevention and healing of stomach ulcers.
When you're eating a pepper and the burn gets to be too much, it's natural to want to douse the flame with water or soak it up with a bland bite of bread. But these things won't work well. Capsaicin is bound tight to nerve receptor sites in the taste buds and is not water soluble. It does mix with fats, oil and alcohol - which may explain why beer makes a better chile chaser than water.
The best fire quencher, though, is milk. And nonfat milk will do. Although it was once thought that fat in the milk stripped capsaicin from its receptor on the taste buds, it is now known that casein, the milk protein, is the active component.
If you don't enjoy the heat but still want capsaicin's benefits, there could yet be a way for you to have your cake and eat it, too. A nonpungent pepper cultivar, the CH-19 sweet, has very little capsaicin but a large amount of a related compound, capsiate.
Capsiate has similar anti-inflammatory and antioxidant effects to its hotter cousin, as well as the ability to increase energy expenditure.
While not yet commercially available, the CH-19 pepper - or an extract of the fruit in the form of a dietary supplement - may in the future do the trick for those who don't enjoy the heat but still want to enjoy the health benefits of chile peppers.
Susan Bowerman, a registered dietitian, writes for the Los Angeles Times.