Certain lipid transfer proteins and protein enzymes in fruit and vegetables have long been linked to allergies. However, right now the jury is still out on whether sensitivity to the salicylates found in plant foods can truly cause adverse reactions.
When one does a search on the internet, thousands of articles that report on the symptoms and causes of salicylate sensitivity come up, and anecdotal reports on the health implications are plentiful.
To add to this, a number of health professionals already take this type of intolerance into consideration in the treatment of patients – also in South Africa.
From the reports, it seems that salicylate sensitivity could very well be a global problem – and one that many people are unaware of. However, scientific research on the topic is few and far between.
Different salicylate compounds
What we do know, is this: all salicylate compounds cannot be tarred with the same brush.
According to experts at FACTS (Food & Allergy Consulting & Testing Services), based in Cape Town, a clear distinction needs to be made between acetyl salicylate and sodium salicylates. Acetyl salicylate, or aspirin, is a synthetic compound, whereas sodium salicylate occurs naturally in a wide range of foods.
Foods that contain salicylates include fruits, such as apricots, strawberries, guavas, dates, plums and grapes, and vegetables, such as cucumbers, mushrooms, baby marrows and peppers.
Other salicylate-containing products include cosmetics, perfumes, toothpastes and herbal remedies.
At this stage, the only salicylate proven to cause an adverse reaction is aspirin – a sensitivity that is more common among asthmatics than non-asthmatics, says FACTS registered dietician Karen Horsburgh.
Up to 25% of aspirin-sensitive individuals also react adversely to the azo dye tartrazine, but it is not yet known whether aspirin and tartrazine cause adverse reactions in the same way.
Level of salicylic acid a factor
So, aspirin-related sensitivity seems to be a real problem. But research hasn't proven that the salicylates found in fruits, vegetables and consumer products cause adverse reactions – not even in aspirin-sensitive individuals, Horsburgh says.
The level of salicylic acid may be the determining factor in terms of salicylate sensitivity.
"The daily dietary consumption of salicylate is estimated to be 10-200mg," Horsburgh says. "One dose of extra-strength aspirin provides 600-650mg of acetylsalicylic acid, which is far more than that which is consumed in a meal made up of many salicylate-containing foods."
Where to from here?
Salicylates are very much a part of our everyday lives. If future research does indeed show that these compounds could cause the proposed adverse reactions – which include headaches, breathing difficulties, wheezing, nasal congestion, itching and abdominal pain – it could be a difficult allergen to eliminate.
While switching to another brand of toothpaste mightn't be a problem, a diet devoid of fruit and vegetables can hardly be considered ideal.
Despite the lack of research, many patients firmly believe that salicylate sensitivity has a negative impact on their lives. Are you one of them? Then speak to a registered dietician. An elimination diet and a greater awareness in terms of product usage could make a difference, but this should never be attempted on your own. – (Carine van Rooyen, January 2007)