Salicylate sensitivity can be a tricky condition to navigate thanks in part to high levels of the chemical being present in many foods said to be “good” for us (i.e. fruits, vegetables, herbs, spices, oils etc.). Studies have shown that cooking food can have many benefits including making food easier for the body to digest and absorb nutrients from (1), improving bile acid binding thus lowering levels of cholesterol in the blood (1), and destroying harmful microbial activity (2) not to mention improving the taste and aroma of food. But what if cooking could also reduce salicylate values in food, thus widening the variety of healthy foods those with a sensitivity can consume?

One study looking into the salicylate content of food, tested foods both cooked (boiled in water and drained) and uncooked to see if salicylate levels varied with processing. What they found was that for a number of vegetables, salicylate levels actually reduced when cooked (3). The researchers claim this may be due to the fact that salicylates are volatile, sublimating when heated (changes from a solid to a gas). Being able to evaporate when heated means the heated food is less concentrated with salicylates, thus, in theory enabling sensitive individuals to consume the food with less side effects.

Another study by Scotter et al. (5) also measuring the salicylate content of food, found that fresh tomatoes, a vegetable notoriously high in salicylates, contained higher levels of salicylates in their raw state than in their cooked equivalent. Similarly, salicylate levels of raw raspberries were found to be much higher than in raspberry jam – the making of which involves heat application. These results suggest that salicylate content may be lost in food processing/cooking.

What these studies highlight is that eating vegetables in their cooked form (e.g. soups, stews, roasts) may be more tolerated in sensitive individuals than eating them raw – a point also highlighted in the RPAH handbook which states that boiling or baking at 200 degrees celsius reduces salicylates (7). An additional step that involves boiling your vegetables first in water, draining them to discard any residue salicylates, then using them in the dish may also be of benefit. Cooking your food when possible may also open the door for foods usually avoided due to their higher salicylate content to be introduced back into the diet – important as a varied diet has been linked to a more diverse microbiome and thus improved health (4).

It’s also worth mentioning here that heat can affect foods in different ways. For example, dried fruits have relatively high levels of salicylates by volume compared to their fresh version of the same volume due to the removal of water during the drying process (6).  

Another little side note in regard to the research, but worthy of mention, was the focus on both free and bound salicylate levels in food – important for understanding what the potential effect the food has on the body (science hasn’t quite figured out yet what happens to bound salicylate in the stomach). For example, a person who eats white potato, which is listed in a number of research papers as “low” in free salicylates, may have a reaction if they are very sensitive due to it actually being a “medium” when taking into account bound salicylates. If a person is able to break down these bound salicylates in the body, thus freeing them up, they could potentially have a greater reaction to the white potato. 

To date, it’s still unclear the degree to which cooking influences the salicylate content of many foods, so careful testing and monitoring of symptoms should be applied when trialing your response to foods in their heated form. For many people, the problem with salicylates involves the accumulation of the chemical in their body over time, causing them to overshoot their tolerance threshold after which symptoms can ensue. Being able to manipulate the levels of salicylate in the diet through cooking even by just a small amount could be the difference between a reaction or no reaction – information I’m sure will be of great interest to the salicylate-sensitive community.

Brigid xx

References

(1) Adriana D.T. Fabbri, Guy A. Crosby, A review of the impact of preparation and cooking on the nutritional quality of vegetables and legumes, International Journal of Gastronomy and Food Science, Volume 3, 2016, Pages 2-11, ISSN 1878-450X, https://doi.org/10.1016/j.ijgfs.2015.11.001.

(2) van Boekel M, Fogliano V, Pellegrini N, Stanton C, Scholz G, Lalljie S, Somoza V, Knorr D, Jasti PR, Eisenbrand G. A review on the beneficial aspects of food processing. Mol Nutr Food Res. 2010 Sep;54(9):1215-47. doi: 10.1002/mnfr.200900608. PMID: 20725924.

(3) Kęszycka PK, Szkop M, Gajewska D. Overall Content of Salicylic Acid and Salicylates in Food Available on the European Market. J Agric Food Chem. 2017;65(50):11085-11091. doi:10.1021/acs.jafc.7b04313

(4) Heiman ML, Greenway FL. A healthy gastrointestinal microbiome is dependent on dietary diversity. Mol Metab. 2016 Mar 5;5(5):317-320. doi: 10.1016/j.molmet.2016.02.005. PMID: 27110483; PMCID: PMC4837298.

(5) Scotter MJ, Roberts DP., Wilson LA, Howard FA., Davis J, Mansell N. Free salicylic acid and acetyl salicylic acid content of foods using gas chromatography–mass spectrometry. Food Chemistry. 2007;105(1):273-279. doi:10.1016/j.foodchem.2007.03.007

(6) Anne R. Swain, Stephen P. Dutton, A. Stewart Truswell, Salicylates in foods, Journal of the American Dietetic Association, Volume 85, Issue 8, 1985, Pages 950-960, ISSN 0002-8223, https://doi.org/10.1016/S0002-8223(21)03743-3.

(7) (2) Swain, A., Soutter, V, & Loblay, R. (2011). RPAH Elimination Diet Handbook with food and shopping guide. Australia: Allergy Unit, Royal Prince Alfred Hospital.