Have you ever felt like the food you eat is causing unwanted symptoms, even if you feel you’re doing things right with your nutrition? Often, it can be healthy foods that contribute to symptom development in sensitive individuals, it is not necessarily about ‘good’ vs ‘bad’ foods.
Food chemical intolerance is something that’s misunderstood by many. Most people think of food chemicals as artificial. Yet many different foods contain natural food chemicals. They include vitamins we need for health and the flavour that makes food so delicious! Salicylates, amines and glutamate are examples of natural chemicals that are likely to upset sensitive individuals. Different foods can have the same type of chemical, and one food can contain several types of chemicals. People can be born sensitive, or environmental triggers, a dietary change or a viral infection can cause symptoms at any age.
What is it?
When foods that contain natural food chemicals are consumed, they would normally be digested and absorbed without issues, however in people who are sensitive, these natural food chemicals can cause unpleasant symptoms. Food chemical intolerance does not trigger an allergic reaction, but rather the chemicals irritate nerve endings in different parts of the body leading to a range of uncomfortable symptoms.
Food chemicals are present in a huge range of foods, with some examples including:
Found in many fruits, vegetables, nuts, herbs, spices, honey etc as well as scents in perfumes and cleaning products
Amines come from the breakdown of proteins so levels are highest in protein foods such as meats, fish and cheese particularly as they mature, as well as ripe fruits such as bananas and tomato
Glutamate is an amino acid found naturally in most foods and is a natural flavour enhancer. It is found in cheese, tomato, mushrooms, stock cubes, soy sauce and is also used in MSG as a flavour additive in various foods.
What are the symptoms?
Symptoms of food chemical intolerance can vary including those in the list below:
- Flu-like aches and pains
- Mood changes
- Asthma or sinus irritation
- Mouth ulcers
- Diarrhoea and/or constipation
How do you get a diagnosis?
If you’ve related to any of the above symptoms, the first step is to speak to both your doctor and a dietitian. Because an intolerance does not involve the immune system, there are no reliable diagnostic tests for food chemical intolerance. Although widely available, tests such as IgG antibody tests are not validated or recommended. These types of tests simply reflect what foods you have eaten recently, not necessarily what foods are causing your symptoms. It is also not possible to guess an intolerance based on symptoms and it is often likely that if you are sensitive to a food chemical, it may be that you are sensitive to more than one.
By speaking with your doctor and dietitian, other underlying causes can first be ruled out before exploring the diagnosis of an intolerance.
This involves a strict elimination diet that should only be done under the supervision of your healthcare team. Elimination diets involve reintroduction phases to test what food chemicals may be causing symptoms for you. The idea is to be able to reintroduce as many foods as possible back into your diet and only avoid or minimise those foods that do cause symptoms. Because of the restrictive nature of these diets, and the steps involved to get the right outcomes, it is recommended you only undertake this process with the guidance of a dietitian who can support you along the way.
Are there treatment options?
Management of food chemical intolerances involves avoiding those foods or specific chemicals that cause uncomfortable symptoms for you and eating those in amounts that are tolerated by your body before symptom development. People with food chemical intolerance will often have a certain threshold level of that chemical before symptoms occur. This will depend on how sensitive you are, and the threshold may also move over time depending on what else is going on. For example, the more stressed you are, the lower you may find your tolerance level before symptoms do occur.
Typical reactions to food chemicals begin within an hour or two and may last a few hours, however, more severe reactions can last days. Eating a small dose of a food chemical your body is sensitive to may not produce immediate symptoms, but consuming many different foods containing that chemical across the day or week can cause levels in your system to build up gradually which then makes it difficult to pinpoint exactly what foods caused symptoms. During your treatment with your dietitian, working out your threshold levels will help you to manage food intake and symptom management long term.