Food intolerance testing

‘Food intolerance’, ‘food sensitivity’ and ‘food allergy’ are terms often confused. Many people think they’re allergic to certain foods, when in fact they’re intolerant or sensitive. Food intolerances or sensitivities are much more common than food allergy (which only affects approximately 3% of the population).

The difference between food allergy, intolerance and sensitivity

Food allergyFood intoleranceFood sensitivity = IgG food intolerance
Reaction timeImmediate reaction (2hr or less)From 1hr to a few hrsUp to 72 hrs after eating
Is it common?Approx. 3% of populationMore common than food allergiesVery common
Number of foods affectedUsually 1 or 2 foodsAny numberAny number
What’s affected?Primarily skin, airways and digestive systemMainly digestive system, skin, airwaysAny organ can be affected
Caused by…Raised IgE antibodyLack of or decreased enzymesRaised IgG antibody
ImpactLife-threateningUsually not life-threateningNever life-threatening
Lifelong?LifelongLifelong but managed through diet / supplementsCan be resolved over time
TestingBlood test or skin-prick test via NHSPrivate or NHS (e.g. hydrogen breath test, lactose/milk tolerance test, elimination diet) Private – food intolerance test, elimination diet

What is food allergy?

Food allergy is an immediate immune reaction to the food, which means your immune system is reacting to the food you eat by creating antibodies called IgE. Usually, your immune system reacts to the protein part of the food (e.g. peanut, milk, egg), but you can be allergic to any food substance. Allergies can happen when eating the food or by inhaling or touching food particles too.

Allergies can be life threating, so speak to your doctor if you suspect anything. The NHS won’t accept results from privately done allergy tests, so to save yourself money speak to your GP first to arrange a test through them. If your symptoms don’t point to food allergy or your results come back negative, then it may be worth exploring food intolerances/sensitivities.

Milk, eggs, fish, crustaceans, tree nuts, peanuts, wheat, soybeans account for 90% of food allergic reactions, but more than 170 foods can cause an allergic reaction.

What is food intolerance?

Food intolerance is a non-immune reaction to food, which means the immune system isn’t involved. Hence the symptoms experienced are because you’re lacking enzymes to digest certain foods. Lactose intolerance, histamine intolerance or gluten intolerance are examples of food intolerances. So, if you’re lactose intolerant, you’re not able to digest lactose (milk sugar) because you have low levels of the enzyme needed, called lactase.

Food intolerance symptoms can be rapid and may include:

  • Diarrhoea
  • Bloating
  • Flatulence
  • Nausea
  • Abdominal pain or discomfort
  • Headaches
  • Rashes, flushing

What is food sensitivity?

When it comes to food sensitivity, your immune system is reacting to the food you eat, but it’s a delayed reaction which is much slower compared to food or intolerance symptoms. Because your immune system is producing antibodies called IgG, food sensitivity can also be called “IgG food intolerance” and many testing companies use the “food intolerance” term instead of “food sensitivity”.

A food intolerance (sensitivity) test checks the levels of IgG antibodies your immune system produces when it comes across food molecules. The higher the number of IgG antibodies, the more sensitive you are to a particular food.

Although food sensitivities are not life-threatening, they are a wide-spread problem which can make you feel unwell and impact your quality of life.

The symptoms of food sensitives include:

  • Digestive problems such as bloating, irritable bowels, diarrhoea, constipation, vomiting, nausea, indigestion
  • Eczema or other skin issues such as acne, rashes
  • Migraines and headaches
  • Dizziness
  • Fatigue
  • Depression and low mood
  • Joint pains
  • Sinusitis
  • Runny nose
  • Dark circle under the eyes
  • Unintentional weight loss or weight gain
  • Bladder control issues

How do I test for food sensitivities?

There are 2 ways to discover what food sensitives/IgG intolerances you may have. You can either follow an elimination diet or do a food intolerance test.

In a nutshell, an elimination diet requires you to eliminate the most common food allergens for a period of time (usually from 30 to 90 days). You then reintroduced each food allergen one at a time to see if they cause any symptoms. However, if you’re sensitive to the food that isn’t the most common allergen, you may see no benefit in following this approach. Moreover, it may take some time to discover which food is causing your symptoms, as you’re only allowed to reintroduce one food every 4 days.

To sum up, an elimination diet is free, but it takes time and dedication. It may be a bit confusing as to what foods to exclude, and it’s also important to introduce new foods into your diet that you don’t normally eat (for example, cassava) in place of the eliminated ones so that you don’t end up with a very restricted diet. You may benefit from talking to a nutritional therapist who can guide you through this process making sure you’re not depriving yourself of essential nutrients.

In comparison, a food intolerance test allows you to identify problematic foods quicker. Companies charge for this and the amount depends on the test and how many foods are being checked. If you’re suffering from food intolerance symptoms which are impacting your day-to-day quality of life, a food intolerance test is probably going to be very helpful in identifying those problematic foods. However, the cost of doing a test can be prohibitive and they may not always show a result if you haven’t had the problematic food for a while.

The benefit of doing a food intolerance test is that it will be able to quickly show which of the foods you eat regularly are potentially problematic. A food intolerance test is also able to highlight more unusual foods which you may not have considered removing when on an elimination diet.

What to do next?

If you aren’t sure whether an elimination diet or a food intolerance test is the best option for you, or if you simply have any questions about the test, please book a free 30-min call with me to talk through your options.