...But we eat it for pleasure.

The average U.S. resident consumes more than 11 pounds of chocolate each year-for reasons that have to do with hedonism, not health. Sweet, fatty foods like chocolate can trigger an addiction in vulnerable people, rewarding them for ingesting such goodies with the release of pleasure- inducing opiates in the brain, studies have indicated (SN: 6/17/95, p. 374).

Now, pharmacologists at the Neurosciences Institute in San Diego report finding that chocolate contains not only its own cannabinoid-a compound that resembles the ingredient in marijuana (cannabis) that induces euphoria-but also a pair of related chemicals that could prolong any pleasurable sensations elicited by a cannabinoid.

In the Aug. 22 Nature, Daniele Piomelli and his colleagues report isolating from cocoa powder and three different brands of chocolate a substance called anandamide, a cannabinoid that occurs naturally in the brain. Like the active ingredient in marijuana smoke, this compound binds to cannabinoid receptors in the brain. However, the two related chemicals that accompany chocolate's anandamide-and that are present in much higher quantities-don't bind to that receptor, Piomelli says. In fact, these chemicals may be more important than the cannabinoid in explaining why eating chocolate makes people feel so good, he says.

When someone eats anandamide or smokes marijuana, Piomelli explains, active cannabinoids hit all areas of the brain, creating a global high. By selectively slowing the breakdown of the body's own anandamide instead- which is what the two related chemicals in chocolate do-this soothing food may prolong natural, more subtle feelings of well-being.

That's the assumption Piomelli's team is now exploring in follow-up tests with animals. After injecting rats with the chemicals that accompany anandamide in chocolate, the group is examining whether the animals experience greater relaxation, less anxiety, or less sensitivity to pain.