Hadley Wood Healthcare Food Sensitivity Test

Our testing method looks for dietary reactions involving a specific antibody known as IgG in your blood.

Our testing method is not a classic allergy test and does not test your blood for the IgE (classic allergy) antibodies that are associated with severe, sometimes life threatening reactions to foods known as anaphylaxis. 

A typical example of allergy or possibly anaphylaxis would be nut allergy. In this case you may have a positive IgE reaction to nuts but might display a negative IgG reaction to nuts using our food sensitivity test. This means that you will still have to avoid eating nuts but equally does not mean that the IgG test was incorrect as this test not test for the IgE allergy reaction but for IgG sensitivity reaction.

Classic IgE allergy is commonly associated with a rapid onset of symptoms very soon after eating the offending food. The more subtle IgG reactions may be related to a delayed onset, with more long term or chronic symptoms being experienced.

The food sensitivity test is an effective, simple to perform and well tolerated method that we have been performing for many years and only requires a finger prick sample of blood.

The results obtained from the test help to guide you to systematically remove certain food(s) in order to help resolve the root cause of some of all of your symptoms.

Many people report the complete return of their symptoms by eating the offending food(s) in large quantities however it may not show up for hours or days which is why clinical trials can be so difficult to fully assess and can sometimes give a negative view for the important role that testing for IgG food antibodies
can play.

However, please note that some medications can negatively impact results. Any medication which inhibits the body’s
ability to produce IgG antibodies either directly or indirectly, will affect the results.

We allocate a 1 hour appointment to accommodate the test procedure and consultation including a discussion of the results that are available during the appointment.

When this test is not appropriate or suitable

• Only suitable for children 2 years and over
• Not suitable during pregnancy or breastfeeding. (We
  recommend waiting 3-4 months after giving birth, and ideally until no longer breast feeding to allow the immune system to return to normal).
• Not suitable for those taking immunosuppressant drugs (eg steroids, see below).
• Not suitable for those taking antibody therapies for autoimmune disease or chemotherapy / radiotherapy for cancer treatment.
• Notes regarding steroid use;
  • The test should not be performed until 4-6 weeks after the last steroid dose has been taken.
  • The test can be taken within the first 4-weeks of starting a steroids prescription.

How does the test work?

The test uses a reaction tray is imprinted with food protein extracts within small surface wells.

We use a finger prick blood sample (50µl) which is diluted and
added to the test tray.

Over subsequent steps the use of detector and developer solutions enables the identification of the presence of food antibodies through the appearance of one or more blue spots in the test tray reaction wells.

The darker the spot, the higher the concentration of IgG antibodies detected to that specific food.

Does the blood need to be sampled at any particular time of day?

No, samples can be taken at any time of the day.

What is an IgG?

IgG stands for Immunoglobulin (type G).

Immunoglobulins are a class of proteins that function as antibodies produced by the immune system in response to foreign bodies entering the body.

There are several different types of immunoglobulins with IgA, IgE, IgG, IgM being the most well-known.

Why do foods cause an IgG response?

Food is generally broken down during digestion into their component parts e.g. amino acids, glycerides etc.

These pass harmlessly through the gut into the bloodstream.

However, occasionally small fragments of partially digested or undigested foods are able to pass through the gut wall into the bloodstream where they are recognised by the immune system as being ‘foreign’.

The immune system responds by making IgG antibodies to these foods.

What is the difference between food allergy and food sensitivity?

A classic food allergy, such as a peanut or shellfish allergy, is usually characterised by an immediate and often severe reaction upon exposure to the offending food.

Symptoms include sneezing, rashes, skin irritation,
swelling and fatigue.

Such allergic reactions involve IgE antibodies.

Food sensitivity tends to be characterised by a delayed onset of symptoms and involves IgG antibodies.

Symptoms may occur several days after eating the offending food, making it difficult to identify the cause.

What is an antibody, and what is the difference between IgG and IgE antibodies?

An antibody is a specialised protein produced by the body’s immune system when foreign bodies (such as viruses, bacteria, partially digested food proteins and toxins) enter the body.

They are produced by special white blood cells called B-Lymphocytes as a defence against these foreign substances.

IgE antibodies are a type of antibody mostly found in the skin, nose, lining of airways and lungs, and are usually produced in
classical allergies and are stimulated in response to type I innate immune allergic reactions.

IgG antibodies are the most abundant antibodies in the body and are associated with type 3 delayed immune allergic reactions to digested foods, named food sensitivities.

The testing method we use detects IgG antibodies.

It has been shown, by various studies, that if foods producing high IgG levels are eliminated from the diet, the symptoms associated with these foods can be reduced.

Do high IgG antibody levels cause symptoms?

When a food causes the body to produce high levels of IgG then these antibodies combine with the protein in the food to form an ‘antigen-antibody complex’.

These complexes are usually eliminated by other cells in the
immune system.

However, if the immune system is overloaded, these insoluble molecules become deposited in tissues within the body, where they may promote chronic irritation, inflammation and the subsequent production of symptoms.

Is it possible to have high IgG levels and not experience symptoms?

Yes, some people do have high IgG levels to certain foods but do not have any symptoms at all.

This is most likely due to their immune system being extremely efficient at clearing away the antigen-antibody complexes
before they have a chance to be deposited in the tissues and cause a problem.

Certain foods are more likely to show a positive results, e.g., wheat, dairy and barley. The reason for this is that these foods are consumed on a regular basis in our diet and along with digestive issues this can increase the likelihood that the body may react to them.

While an elimination diet will always be the gold standard, the benefit of doing a food sensitivity test is that it will be able to quickly show which of the foods that are eaten on a regular basis, are a potential problem.

In addition, the test is able to highlight more unusual foods which you may not have considered removing from their diet.

I have been avoiding a food for several months/years; will this affect my test results?

The IgG food sensitivity test is based on your immune system producing antibodies in response to eating certain foods.

If you have been avoiding a particular food, your body may be producing insufficient antibodies to be detected by the test.

You may, therefore, show a negative response.

To ensure a reliable result, you should include that food in your diet daily for at least 1 week (one portion per day) before testing.

However, if you know that the food concerned causes you extreme symptoms, do not re-introduce that food at all.

Do I need to re-introduce foods before taking the test – if so, how long for?

In general, we recommend that you follow your normal diet, so that the test will reflect what you usually eat.

However, if you have specifically avoided a food for more than three months (e.g. cow's milk), which used to be part of your normal diet and you would like it tested, we would recommend that it is reintroduced.

The recommendations are to reintroduce the food for 1 week, eating a normal portion of that food at least once daily before taking your blood sample.

If symptoms occur on reintroducing the food, we recommend that you discontinue that food and conclude you are still sensitive to it.

If cow’s milk comes up positive, does that mean that I am lactose intolerant?

No, not necessarily.

Lactose intolerance is the inability to digest lactose, the major sugar found in milk, and is caused by a deficiency of the enzyme lactase.

The test we perform test only tests your immune system
response to proteins within cow’s milk and not deficiencies in the enzyme lactase.

Therefore, we cannot diagnose lactose intolerance or other intolerances using this test, this is performed using a specific food elimination and rotation diet which we can discuss if needed.

Is gluten-free the same as wheat-free?

No. A product can be wheat-free but not gluten-free and vice versa.

You can buy products that are both gluten-free and wheat-free.

It is important to read ingredient labels to be certain.

The test we use test detects gliadin (gluten) and is included as an independent tested to wheat, barley, and rye.

If you test positive for gliadin (gluten), we suggest you avoid
all gluten-containing grains (even if they show a negative response on your results) and substitute with naturally gluten-free foods, such as quinoa, buckwheat, corn, and oats.

If I come up positive to gluten, does that mean I have coeliac disease?

No.

A positive reaction to gluten on an IgG test is not confirmation of coeliac disease.

Coeliac disease is an autoimmune response to gluten that is a protein that is found in wheat, rye and barley.

It affects approximately 1 person in 100 in the UK and is a life-long inflammatory condition of the intestinal tract.

If you are worried that you may have coeliac disease please talk to your doctor or an experienced health professional.

Is it possible that I am affected by foods that do not show up in my IgG food test?

Yes - some foods may cause a classic allergic reaction involving the production of IgE antibodies.

These will not be detected by the test we perform or any IgG food test.

There are also many foods that can cause a reaction in the body
without involving the immune system but produce symptoms similar to IgG reactions these reactions are referred to as food intolerances.

For example, amines in chocolate, cheese and red wine may cause migraines.

Some food additives such as tartrazine can cause hives, rashes and asthma.

Monosodium glutamate (MSG) in Chinese dishes can produce sweating and dizziness, and ‘Nightshade’ alkaloids in potatoes,
tomatoes and peppers may affect the joints.

Food intolerance may also be due to a deficiency of a particular
enzyme, as in lactose intolerance.

Why does the test not test for sugar or alcohol?

IgG mediated food sensitivity is caused by antibodies directed primarily to proteins.

Sugar and alcohol do not provoke an antibody response as the protein content is too small to be detected by the immune system.

Do I have to avoid my elevated foods for the rest of my life?

No.

Once you have avoided those foods for at least 3 months, and you have noticed an improvement in your symptoms, then you can start to gradually reintroduce the foods into your diet. You should introduce one food at a time, with an interval of 4 days before trying another food.

If you do not notice the return of any symptoms, then you can continue to include that food in your diet on an occasional basis.

You may find a food and symptom diary useful whilst re-introducing foods.

If you are sure you have been avoiding the foods, and
are addressing any leaky gut issues and still do not notice any improvement after 3 months, then you can assume that those foods are not responsible for your symptoms.

I started to avoid foods from my diet, and now I feel a lot worse, is this normal?

This is a normal reaction for many people in the first few days after excluding a food or foods, due to ‘withdrawal-type’ symptoms.

It is quite common to feel worse for a few days, but this phase soon passes, and an improvement is usually noticed within a few days.

Why do I sometimes feel better after immediately eating a food that I am supposed to avoid?

Some people find that they feel better for a short while after eating foods to which they react to, however, if they continue to eat those foods, the symptoms return.

Eating more of the food once again can brings relief, creating a vicious cycle of addiction that is difficult to break.

This can be overcome by strictly eliminating the reactive food for a minimum of 3 months.

I have been told to eliminate ‘x’ from my diet, but have not eaten it for years, why do I have a positive result?

This is because either;

a) you have eaten ‘x’ hidden in other foods (it is very important to check ingredient labels carefully)

b) you have eaten foods within the same food family with an almost identical protein structure, or been exposed to an allergen that is similar to the antigen in the food and these can result in IgG antibody productions, known as cross reactions.

We can discuss cross reactions where appropriate.

I have a lot of positive results, how do I cut out everything?

If you have a lot of positive results, it can be a very daunting task trying to cut out many foods whilst maintaining a nutritionally well-balanced diet.

In these cases, we advise and help you to avoid those foods with the highest positive response, and to rotate foods with lower positive results, consuming these foods no more than once every four days.

What does it mean if I have lots of positive results?

Potentially, you may have a condition known as ‘Leaky Gut’.

What is Leaky Gut syndrome?

In some patients, inflammation or irritation of the intestinal lining allows partially digested foods to leak through gaps between cells in the intestinal wall into the bloodstream.

This condition is called ‘Leaky Gut Syndrome’ and patients with this condition typically have high levels of antibodies to multiple foods.

We can discuss leaky gut and help you manage this where appropriate.