**3. Dietary source of salicylates**

#### **3.1 Previously**

The occurrence of "natural salicylates", such as SA, in strawberries and other fruits was raised in the Lancet in 1903 [15] and the matter of whether these natural salicylates were superior to synthetic salicylates was the subject of a JAMA editorial in 1913 [16]—no superiority was concluded! Interest then appeared to wane until re-invigorated by the popularity, from 1970, in therapeutic trials—arising from the apparent cross-reactivity of tartrazine and aspirin—of exclusion diets.

#### **3.2 Background**

Many plant derived non-nutritive compounds exert, in mammalian systems, biological activities that may have an impact on health and disease risk [17] and we proposed [18] that SA might provide a link between aspirin, diet and the prevention of colorectal cancer (CRC). There is good evidence that the regular intake of aspirin decreases the risk of developing cancer [19]. A mechanism for platelet mediated CRC tumorigenesis has been proposed [20]; that would, of course not be attributable to SA itself but a more balanced view is that both constituent groups of aspirin (acetyl and SA moieties) contribute to the anti-cancer effects [21].

Assessment of the extent of the contribution of diet to SA in blood and urine cannot be easily inferred from direct analysis of its concentration therein. There is considerable variability in peak serum levels of SA in subjects receiving a standard dose [7] while urinary salicylate is influenced by urine flow, pH, the presence of other organic acids and the saturability of SU formation and/or excretion [2].
