Background and methodology:
Salicylic acid is a chemical signal in plants infected by pathogens and is responsible for the anti-inflammatory action of aspirin. Patients who take aspirin have a reduced risk of developing atherosclerosis and colorectal cancer. Dietary salicylic acid also may help to prevent these conditions. Foodstuffs made from plants grown organically, which are not protected by the application of pesticides, may therefore contain more salicylic acid than those made from non-organic plants. The objective of this study was to determine if organic vegetable soups have a higher salicylic acid content than non-organic vegetable soups. The salicylic acid content was determined for organic and non-organic vegetable soups that were purchased from supermarkets. Salicylic acid was identified by varying the chromatographic conditions and comparing the retention times of the unknown substance in the extracts with salicylic acid; by treating extracts of the soups with salicylate hydroxylase; and by using Gas Chromatography- Mass Spectrometry (GCMS). Salicylic acid was determined by using high-performance liquid chromatography (HPLC) with electrochemical detection.
Salicylic acid was present in all of the organic and most of the non-organic vegetable soups. The median content of salicylic acid in the organic soup was 117 nanograms (with a range of 8 to 1040), compared to 20 nanograms for the non-organic vegetable soups (with a range of 0 to 248).. The organic soups had significantly higher salicylic acid content, with a median difference of 59 nanograms. The finding that organic vegetable soups contained more salicylic acid than non-organic ones suggests that consumption of organic foods may result in a greater intake of salicylic acid.
Gwen J. Baxter, G. J., Graham, A. B., Lawrence, J. R., Wiles, D., Paterson, J. R. (2001). Salicylic acid in soups prepared from organically and non-organically grown vegetables. European Journal of Nutrition 40(6), 289-292