The salicylate sensitivity difficulty

by andrew.mcnulty / 19 November, 2011
Plants use salicylic acid as a natural defence against pathogens but it can cause problems for some people.




Question: Why do organic foodstuffs contain more salicylates than other foodstuffs?

Answer: Decades ago the words “organic food” might have brought to mind images of oddly shaped fruits and vegetables in tiny specialty stores. But organics are now mainstream, with the New Zealand organic industry clocking up $485 million of domestic and export sales in 2009, up from $140 million in 2005, according to Organics Aotearoa New Zealand.

And nearly a quarter of organic sales within New Zealand were for fresh fruit and vegetables; a further 38% were for processed organic foods. Organic produce differs from conventionally grown produce in that little or no pesticide, herbicide or chemical fertiliser is used. Instead, growers mostly use such things as manures, composts and natural predators.

Plants also have innate defence systems. Salicylic acid functions as a chemical signal in plants, with levels increasing when plants are infected by pathogens. It’s thought salicylic acid helps to protect plants from attack, essentially working as a natural pesticide. As external pesticides aren’t applied to organic plants, researchers have wondered whether they would produce more salicylic acid than non-organically grown plants.

A 2001 British study, published in the European Journal of Nutrition, investigated this and found soup made from organically grown vegetables contained more salicylic acid than soup made with conventionally grown ones. In addition, a 2008 study, published in the same journal, found that organically grown tomatoes contained more salicylic acid than conventionally grown tomatoes.

Which foods contain more salicylic acid isn’t important to most of us. But for those who have a salicylate sensitivity, this knowledge is critical. A salicylate sensitivity isn’t a food allergy but rather a form of food intolerance. That is, the body can handle only a certain amount of salicylates at one time; if more salicylates are consumed, then uncomfortable symptoms can develop, such as chronic urticaria (hives), eczema, asthma, nasal polyps, sinusitis, rhino conjunctivitis and stomach aches.

Dr Vincent Crump, an Auckland-based allergy specialist, has seen patients develop hives when they’ve consumed very large quantities of organic fruit and vegetables; hence moderation is always a good idea, even when it comes to nutritious foods like fruits and vegetables.

Question: My son has had a skin rash (cholinergic urticaria) for several years with no identifiable causes. A friend told me it could be an underlying salicylate intolerance. I found the information on the internet about salicylates highly confusing. How can he meet his vitamin, mineral and essential oil needs if he has to avoid most vegetables and fruit?

Answer: Cholinergic urticaria is sometimes called “heat bumps”, as this form of hives is associated with exercise, hot showers and stress. Symptoms include an itching, burning, tingling rash and sometimes systemic complaints such as wheezing. Urticaria related to a salicylate intolerance has regular small and large plaques that can join up to form very large lesions, but this is not the case with cholinergic urticaria, which typically has small pinpoint hives, says Dr Crump.

Before you consider dietary changes, consider taking your son to a qualified allergy specialist, if you haven’t already. This will help determine whether his rash is cholinergic urticaria or a salicylate intolerance, as there is always a possibility he was misdiagnosed. Keeping a diary of the foods he eats and when symptoms occur may also help you determine whether there’s a link between his diet and symptoms. If a salicylate intolerance is suspected, an allergy specialist and/or a registered dietitian can help you modify your son’s diet to improve his symptoms.

Salicylates are found in most fruit, particularly berries and dried fruits, herbs, spices and vegetables. This doesn’t mean these food groups must be avoided; rather the goal is to reduce salicylate intake to a level where symptoms are well controlled. With the right information you can create a healthy low-salicylate diet; for example, replacing broccoli (high in salicylates) with cabbage or cauliflower (low in salicylates, and berries and grapes (high in salicylates) with pears and bananas (low in salicylates).

Email: nutrition@listener.co.nz, or write to "Nutrition", c/o Listener, PO Box 90783, Victoria St West, Auckland 1142.
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