I get a lot of questions about low salicylate diets, so I did some research! The Problem with Diet Restriction Lists, is a great introduction to this article.
What are salicylates?
Salicylates are a general term for several related compounds in plants. The most well-known compound is acetyl salicylic acid (ASA) - the active ingredient in aspirin. ASA was originally isolated from willow bark. Food salicylates are mainly in the non-acetylated form, so are a little different than acetyl salicylic acid (ASA). They are considered phytonutrients (naturally occurring chemicals in plant foods with health benefits – particularly anti-inflammatory).
Can low salicylate diets improve health?
Dr. Feingold first popularized the concept of sensitivity to food salicylates in the 1960’s and 70’s. The Feingold diet (reduced salicylates, food colors, certain additives, etc.) was promoted to treat hyperactivity in children. In the 1980’s a research team at the Royal Prince Alford Hospital (RPAH) in Australia studied a diet that eliminated the above compounds, plus amines and glutamate. Both the Feingold and the RPAH diet are still being promoted, but are not widely accepted in the medical community.
Research interest has shifted toward low salicylate diets for individuals that are sensitive to ASA (aspirin). A recent Canadian study, demonstrated improved nasal symptoms when subjects with aspirin exacerbated respiratory disease followed a low salicylate diet compared with their usual diet (they followed their usual diet or a low salicylate diet for six weeks and then switched). Their symptoms were evaluated by a physician before the study started and at the end of each diet. The physician did not know what diet the subjects were following (physician blinding). These results are exciting because it is the first scientific study evaluating a low salicylate diet (as the only restriction). Some internet websites have used this study as proof that a low salicylate diet is effective, but it is important to keep the following in mind:
- It was a small study (larger studies with more subjects would be needed to make any firm conclusions).
- It is hard to know if the benefit of the low salicylate diet was due to restricting salicylates or a different dietary component. As I will discuss in more detail in the next section, food salicylate levels are variable, so it is hard to define an exact low salicylate diet. Many of the restricted foods are also high in other compounds (e.g., histamine, other diamines, glutamine, etc.)
- Symptom improvement may have been due to a healthier diet. When the clients were following the low salicylate diet, they may have paid more attention to what they were eating and made healthier choices. The healthier choices, not the restriction, may be the reason for symptom improvement.
- This study looked at a very specific group – those with aspirin exacerbated respiratory disease. A low salicylate diet may benefit this group, but that does not mean that it would benefit people without this condition.
Despite the drawbacks, these results are exciting and will hopefully encourage future research.
Salicylates in food
Defining a precise list of high salicylate foods is not possible due to the lack of research and tremendous variation. The most recent information comes from the article: A systematic review of salicylates in foods: estimated daily intake of a Scottish population. For many foods, there was only one sample, but for the foods with more than one sample, there was great variability. For example, the five samples of blueberry ranged from 0.33 – 27.80 mg/kg and the three samples of chili powder ranged from less than 0.2 – 1466 mg/kg. Salicylate content is affected by growing conditions (soil, temperature, etc.) and storage/processing. Therefore, the salicylate levels of food grown in one geographical location, such as Australia (where most of the original research was done) may be very different than another location.
- Many conflicting low salicylate diet lists are available on the internet. It is impossible to say which one is “right” considering the variability described above. Here’s a link to a diet written by a well-known expert dietitian, Dr. Janice Joneja.
- If you tolerate ASA (aspirin), dietary salicylate sensitivity is unlikely.
- There are no medical tests to diagnose dietary salicylate sensitivity.
- If you are sensitive to dietary salicylates, your tolerance will vary with the salicylate level in the food (which is inconsistent, as described above). In other words, a food may bother you one day, but not the next.
Not sure what to eat? I can help you sort through the confusing information and make a meal plan.