Thank you for your inquiry.
First of all, I believe it is important for you to understand that the role of a salicylate-free diet in treating allergic disease is highly controversial, and to my knowledge there is no definitive evidence that such a diet plays a role in many conditions where it has been tested. We have one previous entry on the Academy website regarding salicylate-free diets in relationship to aspirin-exacerbated respiratory tract disease, and as you can see from this entry, such a diet has not been documented to improve symptoms in this disorder. You might be interested in reviewing this entry which was entered on our website on 2/21/2012. Simply enter “salicylate” into the search box, and it will take you to the entry.
The other issue is how strict such a diet may need to be, and unfortunately, there are no studies to my knowledge that have evaluated “threshold doses” of salicylates that consistently will produce a reaction in conditions which have been attributed to salicylate sensitivity.
However, the best source for the contents of salicylate in various foods is from an article entitled “Salicylates in Foods” which appeared originally in The Journal of the American Dietetic Association, Volume 85, Number 8, August 1985. You will find in this article a very comprehensive list of the amount of salicylates contained in a number of different foods. Included in these are the amount of salicylates found in coffee. This appears in Table 1, which is located on Page 955. This article is available to you free of charge online. I have copied for you below a link to the article. You can click on the link and go directly to the article. If this fails, you can copy the link and paste it into your web browser, and the article should be available to you.
As you will see from this table, it is not simply a matter of decaffeinated versus caffeinated coffee, or coffee per se, since different amounts of salicylates are present in different brands of coffee, and therefore you will have to know the particular brand to be able to tell how much salicylate is contained within the coffee. Complicating this issue is that when you review the list you will see that there is a greater variety of brands of coffee now than when this article was printed, and therefore to really be able to tell, you would need to write a letter to the manufacturer of the coffee to learn whether or not salicylates were present and to what extent.
As a rule, however, decaffeinated coffee is felt to have less salicylate in general than caffeinated coffee; that is, at least the impression one gets from looking at the lay literature in this regard. However, I am not aware of any definitive documentation of this observation.
In summary, the most comprehensive and trustworthy list of foods containing salicylate, to my knowledge, is contained in the article which is cited above. There are, however, many articles online in the lay literature which list salicylate-free diets. The scientific documentation of the contents of these diets, however, is not established. In addition, as far as coffee is concerned, the amount varies from brand to brand, and for any accurate determination, you would need to contact the manufacturer and ask for the salicylate content in their product.
Even knowing this, however, since we do not know the threshold dose of salicylates that produce reactions in various conditions, the only safe thing for you to do if the patient really needs a salicylate-free diet is limit the use to a brand which contains no salicylates.
Thank you again for your inquiry and we hope this response is helpful to you.
Phil Lieberman, M.D.