Salicylic acid in the serum of subjects not taking aspirin. Comparison of salicylic acid concentrations in the serum of vegetarians, non-vegetarians,and patients taking low dose aspirin

Aims-To determine serum salicylic acid concentrations in non-vegetarians an d vegetarians not taking salicylate drugs, and to compare these concentrati ons with those found in patients taking aspirin, 75 mg daily. Methods-Serum samples were obtained from vegetarians (n = 37) and nonvegeta rians (n = 39) not taking salicylate drugs. Non-vegetarians sand vegetarian s were recruited from the community and from a Buddhist monastery, respecti vely, in Dumfries and Galloway, Scotland. Patients (n = 14) taking aspirin (75 mg daily) were recruited from the Dumfries diabetic clinic. Serum salic ylic acid concentrations were determined using a high performance liquid ch romatography method with electrochemical detection. Results-Salicylic acid was detected in every serum sample analysed. Higher serum concentrations of sarlicylic acid were found in vegetarians than nonv egetarians: median concentrations of 0.11 (range, 0.04-2.47) mu mol/litre a nd 0.07 (range, 0.02-0.20) mu mol/litre, respectively; the median of the di fference was 0.05 mu mol/litre (95% confidence interval fbr difference, 0.0 3 to 0.08; p < 0.0001). The median serum concentration of salicylic acid in patients taking aspirin (75 mg daily) was 10.03 (range, 0.23-25.40) mu mol / litre, which was significantly higher than that found in non-vegetarians and vegetarians. There was overlap in serum salicylic acid concentrations b etween the vegetarians and patients taking aspirin. Conclusions-Salicylic acid, a nonsteroidal anti-inflammatory drug, is prese nt in fruits and vegetables and is found in higher concentrations in vegeta rians than non-vegetarians. This suggests that a diet rich in fruits and ve getables contributes to the presence of salicylic acid in vivo. There is ov erlap between the serum concentrations of salicylic acid in vegetarians and patients taking aspirin, 75 mg daily. These findings may explain, in part, the health promoting effects of dietary fruits and vegetables.