What's the difference between a food allergy and an intolerance?

In the first part of our series on allergies, naturopath Natasha Berman explains the difference between a food allergy and an intolerance. 

Do you feel queasy after eating cake, bloated after bagels, or rashy after ratatouille? Maybe you have noticed your child has a spot of eczema, or has trouble sleeping after certain meals. You're not alone.

Many people have adverse reactions to all kinds of foods; most of these are caused by food intolerance and not a food allergy. There is a huge misunderstanding about these terms and they are frequently confused and misused. In my clinic, I often hear people say things like, "Oh, I think I'm allergic to…" I really do cringe when I hear this, as the word "allergic" has become almost redundant in its overuse. Although allergies are definitely on the increase, they are still relatively uncommon, whereas at least 50 to 60% of the population suffer from food intolerance.

WHAT IS A FOOD ALLERGY?
The term food allergy relates to immune reactions mediated by the immunoglobulin E (IgE). An immunoglobulin is a protein that carries out various roles in the body's immune response. Our bodies contain five of these: Immunoglobulins G, A, M, D, and E. Immunoglobulin E triggers the most significant reactions. However, not all food reactions are related to our immune system and this is where the confusion arises. For example, tyramine - found in strawberries, cured meats, and cheese - can trigger migraines in some people. This is a brain reaction, not an immune-based reaction. Therefore, these food reactions cannot be picked up via immune testing, such as blood or skin-prick testing.   

True food allergies are mediated by IgE immune reactions. These reactions are almost always immediate in their manifestation, and therefore, most often can be traced back to a particular cause, whether it be a reaction via inhalation or ingestion, or from coming into contact with the skin. These immediate reactions affect the health in a rapid manner and can be life-threatening, ie. swollen lips and tongue or asthma attack. Peanut allergy and shellfish allergy would perhaps be the most well-known of these IgE immune reactions. Anaphylaxis is an extreme physical reaction, and often requires adrenalin to counter the extreme stress-reaction caused in the body.

ALLERGIES AND FOOD INTOLERANCE ARE ON THE INCREASE
Although less people are affected by food allergies than food intolerances, the effects of allergies are more severe. Allergy is ranked as the sixth leading cause of chronic disease today, according to records at the American Academy of Allergy, Asthma and Immunology. Research from the UK has come to similar conclusions. Atopic dermatitis (discussed in Treating eczema naturally) and allergic rhinitis have been increasing rapidly since the mid 1980s.

Food intolerance reactions are often mediated by immunoglobulin G (IgG). Because these reactions can take up to 72 hours to become apparent after exposure, it can be very difficult to pinpoint the trigger food or substance.

Another thing I typically hear from clients in my clinic is, "I know that wheat affects me, but I've done skin prick tests and blood tests, and they come up negative."

This makes sense, because food intolerances are not mediated by IgE as food allergies are, which means they will not be picked up via blood or skin prick testing.

The latest figures coming from Allergenics Allergy Testing Service (www.allergenics.co.nz) show that at least 55% of the population suffers from food intolerance, and this number continues to grow.

SYMPTOMS OF FOOD INTOLERANCE
The most common symptoms that I see in my clinic are:

• Digestive problems: Abdominal bloating/pain, burping and wind, indigestion, weight gain, IBS (irritable bowel syndrome), constipation/diarrhoea.
• Respiratory problems: Sneezing, mucus, coughs, rhinitis/sinusitis, itchy eyes, glue ear and ear infections.
• Mental/emotional issues: Anxiety, ADHD, behavioral problems, lack of concentration, headaches/migraines, insomnia, dark circles under your eyes, depression, food cravings, irritability.
• Skin and immunity issues: Aching muscles/joints, arthritis, asthma, eczema, hives, itching, psoriasis, skin rashes, sick a lot.

SO PROVE IT
So how do we prove that you are suffering from food intolerance and not allergies? This is where a lot of the controversy comes in. Because the immune system is not necessarily involved in the cause of food intolerance, medical tests such as blood tests and skin prick tests may not be helpful. Some people need no more proof than simply removing the food item from their diet. The associated symptoms simply disappear; however, for many people, as multiple foods can be involved, the ability to pinpoint the suspect food items is nothing more than a guessing game. Also, the relationship between your body, stress, and underlying dysbiosis (lack of beneficial good bacteria) in the gut can have a huge effect on your body's sensitivity.

On top of that, we have foods that contain high levels of substances which provoke intolerant-like reactions, eg. sausage, wine, tuna, spinach, and tomatoes all contain high levels of histamine, as do some seafoods, strawberries, chocolate, bananas, papayas, and alcohol.

Other foods contain a natural substance called tyramine, which causes the blood vessels to constrict; for example, cabbage, cheese, citrus fruit, seafood, strawberries, salami, cured meats, and potatoes.

Also, additives such as MSG, sugar, food colourings, and preservatives can affect brain patterns and cause aggression, behavioral problems, and migraines.

FOOD INTOLERANCE TESTING
Diagnosing food intolerance is not an exact science because of the many different types of reactions that can occur. These are the most common tests available:

• Allergenics allergy test. This is a convenient, non-invasive, safe test with a high sensitivity to all kinds of reactions. It's done in a controlled lab environment with qualified health professionals. There is a small cost, and it takes two to three weeks for results.
• Challenge test. There is no cost involved in this test, which is sensitive to reactions. However, it's time-consuming, with no standard way to confirm results. It requires thorough compliance and it's difficult to assess multiple intolerances. Also, there's a possible danger of severe reaction.
• Skin prick tests. This test is good for inhalant substances and good for IgE reactions, but it's invasive. It also shows a poor sensitivity to food intolerances, which are not IgE reactions.
• Pulse test. This is another test with no cost that is sensitive to reactions, but it's very time-consuming and the results are difficult to confirm. It requires thorough compliance. Also, there have been few clinical trials of this method.
• ELISA IgG test. This test is sensitive to IgG reactions and there is clinical evidence that it's useful. However, it's very expensive, and IgG results may vary from lab to lab, depending on the source of the antigens used.

YOU ARE WHAT YOU EAT?
We have learned that at least half the population suffers from a food intolerance, although we do believe this figure to be much higher.

Some of the most common causes of food intolerance (I discuss these in more detail HERE) are:

• Overconsumption of the same food
• The addition of food additives, preservatives, colourings and favour enhancers such as MSG
• Irritable Bowel Syndrome (IBS) and Leaky Gut
• Lack of good intestinal bacteria
• Excess stress
• Prescription and over the counter drugs
• Food addiction
  

I work with allergies and food intolerances every day in my clinic, and love seeing the improvement in my clients' health during the course of our treatment. My basic treatment protocol is as follows:
1. Allergenics allergy test to find out suspect foods and substances causing the system harm.
2. Elimination of foods (indicated in test results) and tweaking of diet plan.
3. Supplementation to address clients' specific symptoms, such as bloating or imbalance of beneficial bacteria.
4. After three months, Allergenics retest, and follow up along with re-introduction of some foods.
In part two of this article, we will take a in-depth look at the causes of food intolerances and how to eliminate and treat them.

Read 'Food intolerances Part 2' here