Food Intolerances and Allergies – What’s the Difference?

We often hear the terms food intolerance and food allergy being used interchangeably, but in reality there’s a significant difference. In this blog we’ll have a look at what happens in both and what lies behind their development.

The Role of the Immune System

Firstly, food allergies involve the immune system, whereas food intolerances don’t. Our immune system is hugely important because it has the job of protecting us from potentially harmful invaders. To do this, it must first recognise what constitutes potential danger as opposed to which substances are harmless.

Once the immune system has identified something as unfriendly it mounts an attack to destroy the invader by releasing inflammatory substances.

Antibodies – Helping the Immune System to Remember

It wouldn’t be very effective if it the immune system had to decide afresh, each time it encountered a substance, whether or not it was a potential danger. So the immune system has a memory for substances it’s encountered before. It does this by producing antibodies which are molecular memories of substances the immune system has identified as an invader.

Problems occur when the immune system reacts to harmless substances as if they were diseasepromoting organisms. Sometimes the food we eat can be interpreted as foe rather than friend.

Classical Food Allergies

Classical food allergies involve the production of antibodies called immunoglobin E (IgE), which are specific to a particular food. Each time the food is eaten, the immune system will remember and mount a similar attack. Effectively it’s an error on the part of the immune system, and the tendency to develop food allergies can be genetic.

A food allergy reaction is usually immediate and predictable, and stable throughout life. If you always suffer from a skin rash after eating strawberries, this is a classical food allergy. They can be life-threatening, as with anaphylactic shock in nut allergies. Such reactions can be sparked off by even just a trace amount of the offending food.

Commonly, food allergies occur to shellfish, eggs, peanuts and soya. Reactions can range from skin rashes to sneezing to digestive problems.

  • Food Sensitivities

A different type of food allergy, not generally recognised by the mainstream medical profession, occurs when the immune system mounts a reaction to a food without IgE antibodies being involved. This is termed a food sensitivity and involves a different type of antibody known as IgG. Often this occurs because food particles which have not been completely digested are absorbed through a permeable intestinal lining. They are unfamiliar to the immune system in that form, so it mounts an attack. Other people can be sensitive to one or more additives used in food processing.

Reactions from food sensitivities can be delayed and symptoms can be diverse, affecting almost any part of the body.

Food Intolerance

Food intolerances don’t involve the immune system but occur when the body reacts to food because it’s unable to digest or break it down effectively. We may lack the enzyme to break down a particular protein, which is what happens in lactose intolerance, or we may be sensitive to certain chemicals naturally present in food.

The effects of food intolerances can be delayed from a few hours to a few days. The severity of the reaction may depend on the quantity of the food is eaten or what other foods are eaten in the same meal. This means intolerances can be difficult to identify.

Food intolerances develop because of problems with the functioning of the digestive system, such as leaky gut.

Common culprits causing food intolerances include dairy, grains and eggs – but practically any food can potentially be a problem.

Management of Food Allergies and Intolerances

Because food allergy reactions aren’t likely to alter over the course of a lifetime, the only effective way of managing them is to avoid the problem food. They’re readily diagnosed by blood or skin-prick tests.

In the case of food sensitivities and intolerances, avoiding the offending food does not address the reason the problem developed in the first place. Unless the health of the digestive system is restored, further sensitivities and intolerances will tend to develop. If the remaining food choices become limited, problems can occur because eating the same foods day in day out is highly likely to bring about trouble tolerating previously ‘safe’ foods.

Symptoms from food sensitivities and intolerances can mimic those from other diseases, making them hard to identify from symptoms alone. Typically a sufferer will experience a range of unexplained symptoms. A functional medicine practitioner would therefore usually recommend a blood test which can detect levels of IgG antibodies to a wide range of foods and additives.

Once problem foods are identified, your practitioner will work with you to support the function of your digestive system, particularly the gut lining, and to improve the digestion of your food. This may help to reduce inappropriate immune reactions and food intolerances.