One of the many challenges that people face when adopting a paleo diet is dealing with the confounding factor of additional food sensitivities. Sometimes these sensitivities are known (perhaps you had allergy or food sensitivity testing done at some point or react so violently to certain foods that it was a no-brainer). Sometimes these sensitivities are unknown and make it frustrating when we don’t experience the instant improvements to our health touted by so many paleo enthusiasts. One such sensitivity is salicylate sensitivity/intolerance.
What are salicylates? Salicylates are the salts and esters of salicylic acid, an organic acid that is a key ingredient in aspirin and other pain medications, is frequently found in cosmetics and beauty products, and is also naturally occurring in varying concentrations in plants. In plants, salicylates act as a natural immune hormone and preservative, protecting the plants against diseases, insects, fungi, and bacterial infection. Why does it always come down to plants’ natural protective mechanisms!?
Salicylic acid is toxic to everyone in high doses. In the case of salicylate sensitivity/intolerance, much smaller doses produce symptoms of toxicity. Salicylate sensitivity/intolerance was initially described in terms of adverse drug reactions; and to date, most of the studies regarding salicylate sensitivity are performed in the context of drugs and medications that contain salicylates and/or salicylic acid. Although the research into this intolerance is still limited, the definition has expanded to a more inclusive definition including sensitivity to foods and to cleaning and beauty products that contain high levels of salicylates1,2. The typical reactions are gastrointestinal and/or asthma-related and/or what is called pseudoanaphylaxis (the symptoms of anaphylaxis through a non-IgE antibody mediated pathway). Symptoms of salicylate sensitivity include:
- Itchy skin, hives or rashes
- Stomach pain, nausea and/or diarrhea
- Asthma and other breathing difficulties, such as persistent cough
- Swelling of hands, feet, eyelids, face and/or lips (angioedema)
- Changes in skin color
- Sore, itchy, puffy or burning eyes
- Nasal Congestion or sinusitis
- Memory loss and poor concentration (linked to ADHD)
- Ringing in the ears
- Depression and anxiety
Salicylate Intolerance may be a key player in many gastrointestinal disorders, such as Inflammatory Bowel Disease, Colitis and Crohn’s Disease 3,4,5,6. It is also deeply implicated in asthma (the reason why aspirin and other NSAIDs are not recommended for asthmatics) 4,6,7 and may be linked to Attention Deficit and Hyperactivity Disorder 4. There also seems to be an important link to inflammation since supplementation with high doses of omega-3 fatty acids (in the form of fish oil) reduces symptoms dramatically 8.
There is no diagnostic test for salicylate sensitivity. The only method to determine whether or not you are intolerant to salicylates is to dramatically reduce your exposure from both your diet and your environment and see if you improve. If you do, then the typical recommendation is to consume salicylates and see if your symptoms return.
So, where are salicylates in your environment? I recommend the website www. salicylatesensitivity.com for complete lists of products, medications, and foods which contain salicylates. The following products often contain salicylates (yeah, this list is not fun):
Given how readily salicylic acid can be absorbed through the skin and lungs and enter the bloodstream, these environmental sources can potentially add up to a significant dose. There seems to be good evidence that those with salicylate sensitivity should avoid exposure to skin care and cleaning products that contain even moderate concentrations of salicylic acid.
Where are salicylates in your food? These lists are only those paleo foods that are highest in salicylates. There are many others with moderate to high amounts that may also need to be eliminated; however this is probably the best place to start. Many seasonings (especially nightshades) also contain salicylates; although it is debatable the contribution to total exposure given how little is typically used when cooking. It’s also important to note that it’s very controversial whether or not restriction of salicylates from food is important, especially when compared to the much larger doses typically found in medications and possible with environmental exposure.
It’s important to mention that salicylic acid is actually believed to be an essential micronutrient in the human diet, potentially even qualifying it as a vitamin. It also has potential cancer-fighting properties. Does it just come down to dose? Or source (food versus drugs versus environment)? There just aren’t answers to these questions, yet.
There is no doubt that salicylate sensitivity exists but the extent to which diet modifications are necessary is still a contentious issue. Given the role that omega-3 fatty acids (and potentially zinc 9) plays in the severity of symptoms, there is likely a strong correlation between severity of symptoms other health factors (such as insulin sensitivity, leaky gut, inflammation, micronutrient deficiencies, stress and potentially autoimmunity).
Do I recommend eliminating salicylates from your diet and environment? It is worth strong consideration if you suffer the symptoms above after following a standard paleo diet and particularly if you are not seeing improvement with a more restricted version like the autoimmune protocol. In fact, limiting chemical exposure in general is one of the recommendations for all people with autoimmune disease in Practical Paleo. Addressing intake of salicylates from medications is definitely the first step (as these are concentrated and hit the stomach and duodenum with quite a punch, and I mean that literally as these drugs increase intestinal permeability!). Concentrated topical applications such as acne creams, wart removal treatments, and muscle pain creams is definitely the next step. How sensitive you are will determine to what extent you will want to remove salicylates from your environment and potentially even diet.
1. Fitzsimon M et al “Salicylate sensitivity in children reported to respond to salicylate exclusion.” Med J Aust. 1978 Dec 2;2(12):570-2.
2. Fernando SL and Clarke LR. “Salicylate intolerance: a masquerader of multiple adverse drug reactions” BMJ Case Rep. 2009;2009. pii: bcr02.2009.1602..
3. Raithel M et al “Significance of salicylate intolerance in diseases of the lower gastrointestinal tract” J Physiol Pharmacol. 2005 Sep;56 Suppl 5:89-102.
4. Perry CA et al “Health effects of salicylates in foods and drugs.” Nutr Rev. 1996 Aug;54(8):225-40.
5. Pearson DJ et al. “Proctocolitis induced by salicylate and associated with asthma and recurrent nasal polyps.” Br Med J (Clin Res Ed). 1983 Dec 3;287(6406):1675.
6. Sivagnanam P et al “Respiratory symptoms in patients with inflammatory bowel disease and the impact of dietary salicylates.” Dig Liver Dis. 2007 Mar;39(3):232-9. Epub 2006 Sep 18.
7. Kawane H. “Aspirin-induced asthma and artificial flavors.” Chest. 1994 Aug;106(2):654-5.
8. Healy E et al “Control of salicylate intolerance with fish oils.” Br J Dermatol. 2008 Dec;159(6):1368-9. Epub 2008 Sep 15.
9. Wecker, H.; Laubert, A. (2004). “Reversible hearing loss in acute salicylate intoxication” (in German). HNO 52 (4): 347–51
10. Food lists are from: http://salicylatesensitivity.com