Sometimes all this talk about food allergies and food intolerances can get a bit confusing. Is there actually a difference? Well, the answer is a big “yes”.
Many people think they are allergic to a food when in fact they are intolerant. The key difference between a food allergy and a food intolerance is that unlike food allergies, intolerances do not involve the body’s immune system.
Uncomfortable but not life-threatening, food intolerance symptoms often occur several hours after a food is eaten – unlike the more immediate reaction you get with a food allergy, which can sometimes cause life-threatening anaphylaxis.
To understand this better, let’s take a closer look at with what each means:
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Food allergy |
Food intolerance |
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Description |
If you have a food allergy, it means your immune system reacts to a harmless food as if it’s toxic. Your body triggers an allergic reaction. |
A food intolerance is a bad reaction to something you’ve eaten that does NOT involve your immune system. |
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Symptoms |
Symptoms of a food allergy usually develop a few seconds or minutes after eating the food and may include:
Some people may develop a severe allergic reaction (anaphylaxis), which can be life-threatening. |
Symptoms can sometimes be vague but may include:
Onset of symptoms can be immediate but is often delayed up to 20 hours after the food is eaten. |
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Age affected |
Most food allergies start in childhood and are most common in young children aged less than 5 years. Even young babies can develop symptoms of food allergy. Food allergy affects up to 10% of babies, 6% of children and 2% of adults. |
Adult onset of food allergy is not common. Food intolerance is much more common in adults and can be due to a variety of causes. |
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Cause |
An allergic reaction is often caused by certain types of food. Just 9 foods cause 90% of allergies. Those foods are: peanuts (a legume), tree nuts, eggs, milk (dairy), sesame seeds, fish, shellfish, soy and wheat. However, ANY food can cause an allergic reaction. |
Any food can cause an intolerance. A common one is lactose intolerance, which means you can’t digest the sugar found in dairy products. |
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Life-threatening? |
Yes, in some cases, a food allergy can be life-threatening. A person can go into anaphylactic shock, which means they might have difficulty breathing and/or a sudden drop in blood pressure. This can be life-threatening and you should seek urgent medical help. |
No, symptoms of food intolerance are not life-threatening. |
Diagnosis and treatment
Your GP will ask questions about what symptoms you are experiencing, including when and how often they occur. If the symptoms are consistent with being a food allergic reaction and appear within a few minutes the first time of eating a particular food, then diagnosis of a food allergy is likely to be straightforward. However, your GP can refer for skin prick or blood tests to confirm the allergen concerned. In any case, if food allergy is suspected or confirmed, you should be referred to a specialist for further tests and ongoing monitoring. This may include an oral food challenge. If a particular food allergy is suspected or confirmed, you should not eat the food until cleared by your specialist to re-introduce it to your diet.
Food intolerance is more difficult to diagnose as there are no tests. It may be recommended to keep a food and symptoms diary to check for patterns, and consult with a dietitian. The dietitian may suggest a short-term elimination diet.
Read more about food allergy.
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Food allergy Allergy NZ