Key Topics Covered

Who should and who shouldn’t care about this topic? 

  • Firstly, you should mostly care about this topic if you get symptoms.  
  • If you feel great pretty much all the time, you probably do not need to look into this topic much.  
  • You could make an argument for limiting certain food chemicals or heavily processed foods for most people. But this topic is also covering a lot of natural chemicals that are found in plants as well.  

What symptoms are often caused by food chemical intolerances? 

  • They are super broad
  • IBS symptoms
  • Headaches
  • Hives or rashes
  • Sinus issues
  • Eczema
  • Hyperactivity
  • Fatigue and a bunch of other stuff 
  • As you can tell, because it is so broad, most people can identify some form of the link here 

Personally, I mostly go down this route only for people with relatively severe symptoms, who also have shown a few signs of a linkage e.g. “my symptoms get worse when I do X thing” that lines up with this.

What chemicals are we referring to? 

The main 3 are: 

  • Salicylates 
  • Amines  
  • Glutamates 
  • Food additives such as certain food colours, preservatives and flavour enhancers 

What foods are these found in? 

  • Complete FOOD CHEMICAL ELIMINATION GUIDE
  • Additives – Avoiding/minimising additives can be kind of simple by avoiding a lot of packaged food with long ingredient lists.  
  • Salicylates – Natural chemicals produced by plants for defense against insects, pests, and microbial attacks. They are found in a lot of fruits, vegetables, herbs, spices, tea, coffee, beer and wine. 
  • Amines – More complex and are found in a lot of foods such as fish, cheeses, sauces, chocolate, nuts, seeds, and some alcohol like beer and wine. 
  • Glutamates are often found in aged, fermented extensively cook foods. MSG is probably the most famous example. 
  • An annoying but simple guide is that often the stronger the flavor of food, the more likely it is to have higher food chemical content.  

What is the process? 

  • The gold standard approach to the RPAH Elimination Diet is to go low food chemical for 2-6 weeks. 
  • It’s pretty tough. For example, pears are the only low-chemical fruit. If you broaden it to “medium” food chemicals, apples and bananas are added.  
  • Then you systematically reintroduce foods in a way that allows you to identify what causes your symptoms. 
  • You very likely need a dietitian for this process.  
  • Following this you then go onto an individualised approach that allows you to have as much food freedom as you can while still limiting symptoms.  
  • It is also worth being aware that tolerance changes over time. 

What is the success rate + what does the science show?

  • At this stage it appears to be the best method for identifying and managing food chemical intolerances. 
  • There is a lot of anecdotal evidence. There is a bit of research done with positive outcomes from the RPAH. But it is still early days. 
  • Some of the research is mixed – for example research on MSG by itself has never linked it with headaches in comparison to placebo. But it is common for people to report symptoms when they add it back in following the RPAH elimination diet.  
  • Some aspects look particularly promising, albeit still lacking research – for example ~75% of people with eczma show significant improvement when following a low salicylate diet 

Are there downsides? 

  • It is hard. 
  • Super restrictive & not advised for those with eating disorders  
  • This is even harder if there are already other dietary restrictions like being vegetarian or vegan 
  • A study on salicylate restriction in children found adverse effects in 31/66 children – mainly around things like nutrient deficiencies and food aversions. 4 children were reported to be developing disordered eating.  
  • That’s just salicylates, not even the full diet.  
  • There are a lot of people I would be hesitant to use this diet with. 

Are there easier ways to do this? 

  • One option is to do a modified version of the diet where instead of going low food chemical, you can include some moderate food chemical foods. It makes it less accurate, but also less restrictive. 
  • Another option is to consider targeting certain stuff that might be relevant. Maybe reducing fruit and vegetable intake reduces salicylates. Or maybe limiting additives helps. There are a lot of options. 

Practical Summary

  • Overall the RPAH elimination diet is an incredibly useful tool for identifying and managing food chemical intolerances 
  • But it is not without its downsides – namely being very hard to do & super restrictive  
  • Downloadable food chemical elimination diet guide PDF 

Relevant Links/Resources:

Studies Mentioned:

Relevant Resources:

Related Blog Posts:

Complete Food Chemical Elimination Diet List | What To Eat
RPAH Elimination Diet: A Low-Food Chemical Approach
Is Msg Dangerous or Is It a Safe Flavour Enhancer? Everything You Need to Know