Salicylates are a group of chemicals present in nature and manufactured for various purposes. They can be found naturally in certain foods and are also used in the production of products like aspirin, toothpaste, and food preservatives. However, both natural and synthetic forms of salicylates can cause adverse reactions in some individuals.

Plants produce natural salicylates as a defence mechanism against insects, fungus, and disease. A variety of foods, such as fruits, vegetables, teas, coffee, spices, nuts, and honey, contain these natural salicylates.

On the other hand, the synthetic form of salicylates is primarily used as a food preservative and is present in medications like aspirin and Pepto-Bismol. Salicylate intolerance is commonly linked to the use of medications due to their higher concentrations of salicylates, in contrast to food products like aspirin.

For instance, the typical dietary intake of salicylates ranges from 10 to 200 mg per day. In comparison, a single dose of aspirin can contain 325 to 650 mg of salicylates, depending on the specific type.

Cause of salicylate sensitivity

Although most people can safely consume salicylate-rich foods or take occasional aspirin without adverse effects, excessive intake of salicylates can cause reactions in anyone.

However, people with a sensitivity to salicylates may experience side effects even with small amounts of these chemicals found in foods or products.These people experience a diminished ability to metabolise and efficiently eliminate salicylates.

Salicylate sensitivity is believed to be triggered by an overproduction of leukotrienes, which are inflammatory mediators associated with various conditions such as asthma, allergic rhinitis, anaphylaxis, rheumatoid arthritis, and interstitial lung diseases. The excessive production of leukotrienes, which are regulated by the enzyme cyclooxygenase, is responsible for this overproduction. The accumulation of leukotrienes in the body results in symptoms associated with salicylate intolerance.

While the exact prevalence of salicylate intolerance is unknown, it is more frequently observed in adults who suffer from asthma. In fact, studies indicate that approximately 2-22% of adults with asthma are susceptible to these compounds. Furthermore, research suggests that individuals with food allergies and inflammatory bowel disease have a higher likelihood of experiencing this intolerance.

Symptoms of salicylate sensitivity

Salicylate sensitivity has a range of symptoms that can resemble allergies and other illnesses. Additionally, diagnosing this condition becomes challenging as some individuals only experience symptoms when unrelated allergies are present.

The respiratory tract is primarily affected by salicylate sensitivity, although the skin and intestinal tract may also be impacted. Typical indications consist of  sinus infection, inflammation, nasal congestion, nasal and sinus polyps, asthma, diarrhoea, abdominal pain, gas, colitis (inflammation of the gut), hives, and tissue swelling. It's important to note that the appearance of symptoms can vary among individuals.

The threshold for triggering a reaction differs from person to person based on their ability to metabolise salicylates. Consequently, some people may experience symptoms even with minimal exposure to these chemicals, while others can tolerate larger amounts before experiencing a reaction.

Foods containing salicylates

A variety of foods contain salicylates.

Fruits, vegetables, and spices are typically the richest sources of salicylates, although salicylates can be found in other foods too.

The amount of salicylates in a particular food can vary depending on factors such as growing conditions, preparation methods, and the degree of ripeness.

For instance, dried fruits have higher levels of salicylates compared to fresh fruits due to the dehydration process.

Here are some foods that are rich in salicylate:

• Fruits - Apricots, blackberries, blueberries, cherries, cranberries, plums, grapes, guava, oranges, pineapples, plums, raisins, strawberries, tangerines.
• Vegetables - Alfalfa sprouts, artichokes, beans, broccoli, chicory, cucumbers, eggplant, endive, okra, radishes, spinach, squash, sweet potato, watercress, zucchini.
• Spices - Allspice, aniseed, cayenne, cinnamon, clove, cumin, curry, dill, ginger, mustard, oregano, paprika, pimiento, rosemary, tarragon, thyme, turmeric.
• Other sources - Aloe vera, almonds, chewing gum, cordials, food colorings, fruit flavourings, gravies, honey, jam, licorice, mints, olives, pickles, rum, savoury-flavoured chips and crackers, tea, vinegar, water chestnuts, wine.

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Salicylates can be present in various non-food items, such as:

• Mint-flavoured toothpaste
• Perfumes
• Shampoos and conditioners
• Mouthwash
• Lotions
• Medications

Diagnosis

Although there is established knowledge about salicylate intolerance to medications like aspirin, limited research has been conducted on salicylate intolerance to foods. The standard diagnostic test for salicylate intolerance to medications involves exposure or provocation. This test entails administering a small amount of salicylic acid and monitoring for any resulting symptoms. It is important that only healthcare professionals conduct this test, as serious reactions can occur.

Conclusion

Due to its diverse range of symptoms, diagnosing salicylate intolerance can often be challenging, and treatment options are presently limited. If you suspect that you may be sensitive to salicylates, it is important to consult a healthcare professional for an accurate diagnosis and appropriate treatment.