food intolerance: Frequently asked questions
What is food intolerance?
If you're body cannot tolerate a particular food, or one of its ingredients, then you will experience a reaction - the type of symptoms that arise vary from person to person so it is not possible to say that, for example, apples will cause headaches or milk will cause stomach problems.
I have drawn up a list of symptoms and conditions that have been linked with food problems - it will give you an idea of the range of potential problems. You can be intolerant of any of the following:
- A complete food such as milk, soya, apple, egg, pork, wheat, mushroom, chicken, lettuce, onion, beef, nuts, oats.
- A naturally occurring chemical such as salicylate in many herbs, fruit and vegetables, tyramine in aged meat, cheeses and wine, solanine in vegetables, or naturally occurring Monosodium Glutamate (MSG) Details of food chemicals can be found in the library.
- An added ingredient that does not occur naturally in the food - such as a preservative, colouring, flavour or antioxidant. These food additives can be a very hidden problem as not all of them need to be declared on packaging.
- In a complex food, i.e. any processed food, you could be sensitive to one of the ingredients. For example, in bread it is possible to react to wheat, preservatives, flour improvers (such as soya), yeast, or bleaching agents. In a food product such as sausages the list of potential suspects may very well be much longer and could include pork, beef, rusk (wheat, yeast, salt), antioxidants, preservatives, flavour enhancers, colours, herbs and spices.
What is the difference between food allergy and food intolerance?
An allergy causes a very specific immunological reaction in the body that can be observed and can be diagnosed by doctors using various tests.
Food intolerance does not cause this type of reaction and cannot be tested for in the same way. This lack of a specific immune reaction and the inability to test "scientifically" has led some doctors to deny the existence of food intolerance.
One of the big differences between food allergy and food intolerance is that allergic reactions can, for some people, lead to an anaphylactic reaction and these reactions, if not treated speedily, can lead to death. Whilst a food intolerance is unlikely to cause an anaphylactic reaction it can cause extreme reactions that lead to physical and mental health problems and greatly impair the quality of life.
Whilst the medical profession may find it useful to differentiate between food allergy and food intolerance, I find the distinction particularly unhelpful. My own view is that a food allergy is a form of food intolerance it just happens to be one form that can be identified by tests (although this is not always the case).
What causes food intolerance?
There is no simple answer to this.
Many reasons have been put forward including the lack of a particular enzyme, that it is inherited, induced by stress or illness, the result of an impaired immune system, environmental pollution... but no one knows for definite.
I suspect that there will never be a single answer as it seems likely that different forms of food intolerance will be found to be triggered by different factors.
If food was my problem surely I'd know, wouldn't I?
How I wish this I could say yes. Sadly, if you have eaten the same food every day for years you will not know if it is causing a problem. It is only by removing the suspect food from your diet and then testing it that you will know for definite if that food is a problem for you.
The body has an amazing ability to cope and that is what it will do until it reaches a point when it can no longer tolerate the onslaught and more serious health problems begin to emerge. For example, you can have been plagued by minor problems for years then get a nasty virus and find that you simply just do not get well again. You are mystified and so is your doctor. Or, you can change your diet to a more "healthy" one and feel great for a while and then find you are putting on weight, feeling tired all the time, developing joint problems, feeling miserable etc...
Having said all of that, it is possible that you do know and instinctively avoid certain types of food, you may have refused certain types of food as a child but been made to eat them because they were "good for you" (children who are "picky" eaters could be signaling a food intolerance problem) and you may know that some foods give stomach problems or a hangover effect but because you enjoy them or they are "good for you" you keep on eating them.
Why has my doctor never mentioned food as a possible cause of my symptoms?
Our western doctors are trained to look at symptoms and to treat them. Rarely do they look for the underlying cause. So if you present with a rash, migraine, or joint pain you are more likely to be given medication than be offered help with re-evaluating your diet. This is simply their training.
It is also the case that there is no simple test for food intolerance. If a doctor suspects a food problem, other than an allergy, then he has to rely on you to carry out the elimination diet, the testing and has to accept your findings. He has little control and no objective measure of how reliable your findings are.
Many doctors are very uneasy about this situation. Thankfully allergies are now more widely understood and accepted and hopefully, in the future, food intolerance will become more accepted.
Can food really cause all the symptoms you list?
Yes but don't worry if you find it hard to believe. I was a total skeptic myself and I certainly never believed that my multitude of health problems could be simply caused by what I was eating.
Each of the symptoms and conditions has been found, in some individuals, to be caused by food intolerance or food allergy but please do not assume that just because your symptom or condition is listed that food is the cause - check it out with your doctor first.
The information on symptoms is provided solely to give you an idea of the overwhelming range of symptoms and illness that can be caused by food intolerance. It is not intended to diagnose the cause of your problems nor should it be interpreted in this way.
Where can I get tested for food allergies and food intolerance?
I suggest you start by discussing the options with your Doctor. Most doctors are able to make referrals to allergy specialists.
The situation is not so clear cut with food intolerance but before you make any major changes in your diet or invest money in an alternative form of food intolerance testing do talk to your doctor - he may be able to make a referral to a dietician or other specialist or have some valuable suggestions to make.
Can you recommend a doctor in my area?
I get asked this question by people from various countries and I am not able to offer recommendations. The resources needed to store and update this type of information are quite simply out of my reach. You could always ask on one of the allergy discussion lists or forums to see if anyone can make a recommendation.
Can you tell me if my symptoms are caused by food intolerance?
There is a list of symptoms, both physical and mental, given on this site which can tell you what types of problems have, for some individuals, been found to be caused by food intolerance or food allergy problems. I am, however, not able to comment on whether any symptoms you may have are caused by food problems.
As each individual is unique and the causes of illness can be diverse and complex your first port of call must always be your doctor.
Is it possible to be intolerant of oranges, oats, carrots, lamb, rice, apples etc...?
Intolerance can take place to any food or substance within a food.
Why am I intolerant of oranges, oats, carrots, lamb, rice, apples etc...?
The mechanics of what actually causes food intolerance are not known. It has been suggested that some types are inherited, some as a result of a breakdown in the body's detoxification system, a lack of certain enzymes and so on.
At what age do symptoms occur?
They can occur at any age.
They can also be short term problems or lifelong conditions. If not identified early on then they can lead to more serious problems in later life: for example, colitis in a child that is caused by milk intolerance can lead to Crohn's disease in adulthood.
What are your views on a particular form of food intolerance testing?
I have no specific views on individual forms of testing. All have, to some extent, worked for some people and failed for others.
What you need to know is that there is no single accepted method for testing for food intolerance and that no tests exist to measure food chemical sensitivity.
The one method of testing that I will recommend is one which uses an elimination diet. Details of the type of diet I believe to be the safest are given in the section on getting well and, in more, detail in the book Change Your Diet and Change Your Life.
Is there a cure for food intolerance?
In most cases the cure is to avoid the offending food or, in the case of certain food chemicals, to reduce the amount of foods eaten that are high in the chemical. There is no drug treatment available that will cure food intolerance. If you have difficulty avoiding problem foods then a doctor may be able to prescribe some treatment to help you deal with the symptoms.
You can find out more in Change Your Diet and Change Your Life.