Food Allergy or Food Intolerance?

Adverse reactions to foods are often called many different names including food hypersensitivity, food intolerance, food allergy, and many other medical and non-medical terms.

These names add to the confusion of diagnosing and managing food related problems. By keeping a diary of all suspected food related reactions (written records, photographs and keeping labels of suspected pre-packed foods), this will help to identify which type of food is causing your symptoms. Sometimes the food triggers will be obvious whilst other reactions are very difficult to identify.

Food Allergy

True food allergy is a reaction involving the immune system where the body sees the food as harmful and makes specific antibodies (called IgE antibodies) to ‘fight off’ the allergens found in these foods. This results in the release of histamine and other naturally occurring chemicals in the body. It is this release of histamine and chemicals, which produce the symptoms we recognise as an allergic reaction.

Symptoms caused by an allergic reaction to food can range from skin reactions: which include itching and rashes; swelling, gut symptoms, vomiting, stomach ache, and diarrhoea. Respiratory symptoms such as coughing, sneezing, asthma, blocked or runny nose.

In the most severe cases symptoms may develop rapidly and can be life threatening so require urgent medical attention. Symptoms may include swelling of the lips, tongue, or face, shortness of breath, throat constriction and breathing difficulties. Loss of consciousness can occur in extreme cases. This collection of symptoms is known as anaphylaxis. Normally symptoms arise within a few minutes of eating or coming in to contact with an offending food, although they may be delayed by up to a couple of hours. Those at risk of anaphylaxis should have an adrenaline device available.

Thankfully true food allergy is actually quite rare, affecting approximately 2% of the adult UK population and up to 8% of children.

The foods that most commonly cause allergic reactions are peanuts, tree nuts (such as almonds and Brazils), eggs, milk, fish, shellfish, and sesame. You should be aware that any food can cause an allergic reaction and some foods are more likely to cause reactions in certain ethnic groups.

Food intolerance

Food intolerance is not so clear cut and is a more controversial area. Although not life threatening, it can and often does, make the sufferer feel extremely unwell and can have a major impact on working and social life. Ongoing symptoms can also affect the person psychologically as they feel they will never get better.

Symptoms can affect different people in different ways but usually last for many hours or days depending on the symptoms, and because it is possible to be intolerant to several different foods at the same time it becomes very difficult to determine whether food intolerance is the cause of chronic illness, and which foods may be responsible. Many people with food intolerance have several symptoms. Sometimes the symptoms are vague and not always easily diagnosed. People may complain of non-specific problems such as brain fog, lethargy, headaches, or feeling bloated. These are often additional to bigger problems relating to bowels and skin.

Food intolerance can be caused by several different factors; lifestyles with erratic food intakes and poor nutritional intake or high intakes of refined foods, poor intakes of dietary fibre or high fat diets are just a few examples.

Some people actually lack the enzymes needed to break foods down for example lactose intolerance where the enzyme lactase is not produced in large enough amounts to break down the lactose (milk sugars) in milk.

Others react to the chemicals that are produced naturally in foods such as caffeine, salicylates, and histamine in foods like strawberries, chocolate, and cheese. Another possible cause of food intolerance is to additives in foods, these can be found in the form of sulphites, which are added to processed foods to give them a longer shelf life. They can also be found in fruit drinks and wine. A reaction to a food that has ‘gone off’ such as salmonella poisoning is another type of reaction to a food; such a reaction will usually affect anyone consuming it.

If you would like to book in for a free 30 min consultation with our dietitian and nutritionist Penny Stevenson, please contact us 0131 447 9990 for an appointment.