Food intolerance
Many people think they are allergic to a food when, in fact, they have an intolerance to the food. A food intolerance is an unpleasant reaction to a food, but the reaction does not involve your immune system.
Causes of food intolerance
Food intolerance is different from a food allergy, which involves an overreaction by your immune system. If you have a food allergy, a very small amount of food can trigger an allergic reaction within minutes.
In food intolerance, the symptoms usually begin within a few hours of eating the food, but can be delayed for up to 48 hours and can last for hours or even days.
With a food intolerance, the amount of the food you eat will affect how severe your reaction is.
Common food intolerances are:
Other causes of food intolerances include:
- alcohol
- caffeine
- fatty foods
- spicy foods
- natural food chemicals such as salicylates, amines and glutamates — these are found in many healthy foods and drinks
- some food additives, including colours, preservatives and flavour enhancers.
The difference between coeliac disease and gluten intolerance
Coeliac disease is a condition where your immune system attacks your own body when you eat gluten. This damages your gut (small intestine).
Gluten intolerance (non-coeliac gluten sensitivity) does not cause damage to your intestine, but it can cause symptoms when you eat gluten. Symptoms may include:
- abdominal pain
- bloating
- feeling tired (fatigue)
- headaches
- muscle aches and pains.
Non-Coeliac Gluten Sensitivity — Coeliac New Zealandexternal link
Symptoms of food intolerance
Symptoms of food intolerance can vary from mild to severe, but are not life-threatening. They usually include:
- gastrointestinal problems such as feeling sick (nausea)
- indigestion
- bloating
- pain
- increased farting
- runny poos (diarrhoea).
For some people, symptoms may include:
- skin rashes
- headaches
- worsening eczema or asthma.
Food intolerances can sometimes have the same symptoms as other health conditions. If you have these symptoms, talk to your healthcare provider.
Diagnosing food intolerance
Food intolerance can often be difficult to diagnose. Tests used to diagnose food allergies, such as skin prick tests or blood tests, are not useful for diagnosing food intolerance.
Several tests have been promoted for diagnosing food intolerance and food allergy. These include:
- cytotoxic food testing
- Vega testing
- kinesiology
- iridology
- pulse testing
- Alcat testing
- reflexology
- hair analysis
- IgG food antibody blood testing.
These tests do not have any scientific basis and have not been shown to be accurate or reliable.
You will need to be checked for other conditions that could be causing your symptoms.
It may help to keep a diary to record if certain foods or drinks make your symptoms worse.
The only reliable way to determine if a food or drink is causing your symptoms is to stop eating it for a least 2 weeks and keep a diary of your symptoms.
If your symptoms do not improve, it is unlikely that you are intolerant to that food. If your symptoms get much better, the food is likely the problem.
Treating food intolerance
You can either avoid the identified problem food or reintroduce it gradually to work out how much you can tolerate.
It is best to do this under the guidance of a dietitian, especially if you suspect you or your tamariki are intolerant to several foods.
This is important, as prolonged restrictive diets can lead to problems getting the nutrition you need, particularly for tamariki.