Chili pepper

Collectively, chili peppers are the fruits of several plants in the Capsicum genus, which are members of the nightshade family along with eggplant and tomato. Most North and South American varieties are represented by the species Capsicum annuum, which includes bell peppers, jalapeños, poblanos and cayenne. Of course, the amount of “heat” in each of these peppers varies in intensity depending on specific type and how and when they are harvested. A sensitive palate generally finds bell peppers to be well tolerated. For the culinary adventurous, however, hotter varieties may provide more “kick” than tingles on the tongue. In fact, psychologists equate the tendency to “like it hot” with thrill-seeking behavior that permits the sensation of danger without really compromising physical safety. The technical term for this is “constrained risk,” a strategy employed while watching a horror movie, skydiving, riding a roller coaster, or daring to bite into a hot pepper.

Another reason to get excited over chili peppers is the fact that the phytochemical that lends them heat when ingested also thwarts pain—or a potential mugger. The primary agent in chili peppers is capsaicin, a compound that protects the plant from fungal disease, insects and herbivores. This substance is classified as a vanilloid because it contains a vanillyl functional group that dictates its behavior in chemical reactions. As such, capsaicin targets and bonds to a receptor in sensory neurons called transient vanilloid receptor subtype 1, also known as the capsaicin receptor. When stimulated, these receptors permit specialized molecules called cations to permeate cells, which modifies the electrical charge of the cell. When this event is signaled to the brain, it is interpreted as pain and burning sensations at the site. This is why capsaicin is used in pepper spray to deter a personal attack or curb a riot; when it reaches the membranes of the eyes and lungs, the effect is immediate. It also repels animals and insects. Birds, however, are unaffected by this chemical, even though capsaicin is often added to birdseed to keep squirrels from eating it.

The same material that stops a would-be assailant is an effective anti-inflammatory and pain and itch reliever. It is found in various ointments and creams formulated to ease muscle sprains, rheumatoid arthritis, and pain associated with diabetic peripheral neuropathy, fibromyalgia and shingles. Specifically, capsaicin inhibits the activity of substance P, a major neurotransmitter responsible for producing pain and heat. It’s so effective that it is used in a drug that promotes long-term pain relief for arthritis and post-surgical patients for weeks after a single injection. Research also indicates that capsaicin may reduce arterial plaque and trigger cell death in lung, prostate and leukemic cancers.