What is the Difference Between Free and Bound Salicylates?

by | May 26, 2022

Not all salicylates are created equal. Where some salicylates originate in their free form, others come bound to other compounds (1), the distinction of which is important to understanding the salicylate content of food and how, in turn, they might affect those who are sensitive to the chemical.

Free salicylates are not bound to another compound making them immediately available to the body. Acetylsalicylic acid (a salicylate derivative), or aspirin as it’s more commonly known, is an example of a free salicylate as it’s not linked to other molecules making it a great choice for medicine as it’s metabolised quickly by the body.

Bound salicylates, on the other hand, are complexed with other chemicals, meaning they don’t become active until they are released in their free form. Plant salicylates, while occurring in the free form, can also be bound to many other compounds (e.g. proteins), thus it takes a certain amount of time for the body to ‘free’ the chemical so it can be available for other reactions.

The distinction between free and bound salicylates may be a significant factor in the link between the salicylate content of food and adverse reactions in sensitive individuals. If foods are tested solely for the free form, their potency may be underestimated as bound salicylates, when converted to the free form, may also add to the ‘salicylate load’ and thus trigger symptoms.

As of yet its not clearly understood how exactly the body metabolises bound salicylates. It’s hoped that with further research the full physiological effects of both free and bound salicylates will be made apparent, opening the doors for a more informed dietary approach to salicylate sensitivity.

Brigid xx



(1) Malakar S. Bioactive food chemicals and gastrointestinal symptoms: a focus of salicylates. J Gastroenterol Hepatol. 2017 Mar;32 Suppl 1:73-77. doi: 10.1111/jgh.13702. PMID: 28244660.

DISCLAIMER: This article is for informational purposes only. It is not intended to constitute or be a substitute for professional medical advice, diagnosis, or treatment. 


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