People can make their own salicylic acid (SA), the principal metabolite of aspirin. SA that gives aspirin its famous action on pain, fever, and inflammation is now looking like a star in its own "class" of bioregulators.

Aspirin has been the common name given to acetylsalicylic acid since 1890s. Researchers in the United Kingdom reported their new evidence in the Dec. 24 issue of ACS' biweekly Journal of Agricultural and Food Chemistry. John R. Patterson and colleagues reveal that SA exists in the blood of people who have not recently taken aspirin. Vegetarians had much higher levels, even overlapping those in patients taking low doses of aspirin. The scientists had previously concluded that this endogenous SA came from the diet because SA and its compounds occur in fruits and vegetables.

New evidence relies on the team's studies of changes in SA levels in volunteers who took benzoic acid, also found in fruits and vegetables that the body could possibly use to make SA. The UK team investigated whether the SA source in humans consists solely of the fruits and vegetables they consume, or whether humans manufacture their own SA. Their results suggest that people do make SA.

"If we are right that SA is not just an important phytochemical but also a key biopharmaceutical," they write. "Its circulating level might well be subject to homeostatic control and not be solely influenced by dietary SA with or without benzoic acid intake."