Food Intolerance Or Allergy: What Is The Difference?

Stores and restaurants often promote specialised dietary products. Gluten-free or low MSG are now buzzwords that are found on both packaging and menus, but these often don’t include an easy explanation for exclusion of the specific item.  We find ourselves asking questions like why should these food types be avoided, are they generally harmful or only to certain people?

Let’s unpack this issue a bit more….

What’s the difference?


Understanding the difference between a food intolerance and a food allergy can be quite confusing because both present with almost the same symptoms such as digestive problems like constipation, diarrhoea, bloating or flatulence, nausea and vomiting; skin reactions like hives, eczema or rashes and breathing problems like asthma, sinus infections or inflammation.

A food intolerance or sensitivity is the body’s chemical reaction to a certain food that it cannot breakdown, absorb or digest due to a lack of or absence of a particular enzyme.  Whilst a food intolerance is not life-threatening, it can cause a seriously decreased quality of life due to severe gastrointestinal problems like Irritable Bowel Syndrome.

A food allergy, in contrast, is a condition where eating certain foods causes an almost immediate response in the body when the immune system incorrectly identifies, or overreacts, to the proteins found in some foods as being harmful. It then launches a range of protective measures in an effort to expel the ‘toxins’ from the body. This often involves releasing chemicals, like histamine, which causes inflammation.

Other typical allergic symptoms that do not present with a food intolerance include swelling of the mouth, tongue, throat or face and life-threatening anaphylaxis.

It’s recommended to avoid foods that trigger a reaction for both a food intolerance and a food allergy. In some cases, alternatives can substitute the offending foodstuff, but in most cases it’s recommended that you live without it in order to prevent continued discomfort or illness. Consult a dietician to work out a healthy meal plan so that you get all the micronutrients that your body needs.

It’s imperative to check and understand foods labels or shop at a speciality store as the by-products of the trigger items can often be found as ingredients, albeit in small quantities, in certain foods.

Common food intolerances


1. Lactose

Lactose is a sugar found in dairy products, like milk, and is broken down by the lactase enzyme, which aids in digestion. A shortage of lactase will cause lactose-intolerance and inhibits proper digestion resulting in discomfort like abdominal pain, constipation, diarrhoea and flatulence.

2. Gluten

Gluten is the name given to proteins found in wheat, barley and rye and is commonly found in bread, pasta, cereals, beer and baked goods. Gluten sensitivity is the inability to digest gluten and can result in bloating, abdominal pain, diarrhoea, headaches and rashes.

3. Caffeine

Caffeine is a chemical found in beverages like coffee, tea, energy and fizzy drinks. It’s a stimulant that can increase alertness so it’s very popular amongst the general population. However, there are those with a sensitivity to caffeine where their bodies are unable to metabolise caffeine properly resulting in symptoms like a rapid heartbeat, anxiety or insomnia.

4. Salicylates

Salicylates are natural chemicals produced by some plants, like tomatoes and strawberries, as a defence mechanism against insects. They produce anti-inflammatory properties, which can cause adverse effects like sinus problems and infections, asthma, diarrhoea or colitis.

5. Amines

Amines are found in a range of different foods like cured meats, dried fruit, vinegar, beer and wine. They are produced by bacteria during food storage and fermentation. A common amine is histamine, a chemical found in the body that has a role in the workings of the immune system and digestive process. Those with an amine intolerance are unable to break down histamine properly resulting in symptoms like headaches, itching, skin rashes or low blood pressure.

6. Fodmaps

Fodmaps is an abbreviation for: Fermentable Oligo, Di-, Monosaccharides and Polyols and is closely associated with Irritable Bowel Syndrome. These are short-chain carbohydrates that are found in a range of foods like fruit, vegetables, meat and fish. Those with an intolerance are unable to absorb food properly when it’s in the small intestine. Instead, the unabsorbed food travels to the large intestine where it’s used as fuel for gut bacteria that ferments, resulting in gastrointestinal problems.

7. Sulphites

These are chemicals used as preservatives in food, drink and some medications. They occur naturally in grapes and cheese but are added to dried fruit, pickled or preserved products and condiments. Those who have a sulphite-intolerance could experience symptoms like a runny nose, headaches and rashes.

8. Fructose

Fructose is a simple sugar found in both fruit and vegetables. It’s also a component of most artificial sweeteners and honey. Those with a fructose-intolerance have an impaired ability to absorb this sugar into the blood, so it travels to the large intestine where it ferments and the bacteria produced cause digestive discomfort like acid reflux, bloating and abdominal pain.

Other foods that are commonly associated with intolerances or sensitivities include red and yellow food colouring, additives like monosodium glutamate (MSG) and yeast.

Testing for food intolerance


Unfortunately, there are no medical tests that can be undertaken for a food intolerance so it comes down to common sense and a process of elimination. Cut-out certain foods from your diet that you suspect may be contributing to your symptoms and then slowly reintroduce foods to gauge your body’s reaction. 

Common food allergies


1.Cow’s milk

An allergy to cow’s milk is quite a common food allergy and also occurs when consuming by-products of cow’s milk like yoghurt, milk powder, cheese, butter, cream and ice-cream. Cow’s milk allergy symptoms can include swelling, rashes or hives and gastrointestinal problems like constipation, diarrhoea and inflammation of the intestines.

2. Eggs

An egg allergy can relate to either the egg whites or the egg yolk. It can also only trigger a reaction based on the form of egg. In other words, some people are only allergic to eggs that are raw, not cooked. Common symptoms can include digestive distress, skin reactions and breathing problems.

3. Nuts

An allergy to nuts can include Brazil nuts, almonds, cashews, macadamia, pine and walnuts. There are also a number of food products that include nuts so check labels carefully. Allergic reactions can include life-threatening anaphylaxis.  A peanut allergy is particularly severe. Affected people are advised to carry an autoinjector, like an EpiPen, which administers a dose of epinephrine.

4. Shellfish

A shellfish allergy extends to families of the crustacean and mollusc families like shrimp, crayfish, prawns and squid – amongst others. This allergy can cause severe digestive problems as well as vomiting.

5. Wheat

Having a wheat allergy means that the body has an allergic response to the proteins found in wheat products like bread, pasta and some cereals. While the symptoms can be very similar, a wheat allergy should not be confused with either gluten-intolerance or Ceoliac Disease. Symptoms include digestive distress, swelling, hives and vomiting.

6. Soy

A soy allergy is caused by the protein found in soybeans and, as a result, all the by-products that include soy. Symptoms of a soy allergy can include itching, a runny nose and breathing problems like asthma.

There are many other, less common, food allergies like sesame seeds, peaches, bananas, avocado, celery, garlic, mustard seeds and chamomile, to name just a few.

Testing for food allergies


There are allergy tests that can be taken to determine if you have an allergy and, if so, what you’re allergic to and the severity thereof. The first thing to do is to undergo a dietary review where a full audit of your food intake is analysed against all the presenting symptoms. Thereafter, a simple skin prick test, where a small amount of the suspected food is pricked into the skin, is done to gauge the body’s reaction. In some cases, your medical practitioner may prescribe blood tests for confirmation.

At Topmed we are care about your health so if you suspect that you or a family member may have either a food intolerance or an allergy, we suggest that you check with an allergy clinic for advice. Get in touch today to make sure that you have health cover for yourself and your whole family.


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Food Intolerance Or Allergy: What Is The Difference?