Allergies vs Intolerances

Allergies

An allergy occurs when a person’s immune system reacts to something in the environment that is harmless to most people. These are known as allergens and can be found in dust mites, pets, pollen, insects, moulds, foods, and some medications.

The most common food allergens are:

• Cow’s milk (dairy)
• Egg
• Tree nuts (e.g. walnut, almond, hazelnut, pecan, cashew and pistachio)
• Sesame
• Soy
• Fish
• Shellfish
• Wheat

The signs and symptoms of an allergic reaction might appear immediately after consuming the substance, or symptoms may not occur up to 2 hours later. Most allergic reactions are mild, meaning they don’t cause major problems. This could include hives, welts, swelling of the face/lips/eyes, vomiting, stomach pain or tingling of the mouth.

A small number of people experience a severe allergic reaction called anaphylaxis – which calls for quick lifesaving medication. Signs of anaphylaxis include difficult or noisy breathing, swelling of the tongue, swelling or tightness of the throat, dizziness or collapse.

In summary: It’s important to understand that even very small amounts of certain food can cause a life-threatening reaction if you are allergic to it. If you have a known food allergy, always avoid that specific food.

Food intolerances

It can be easy to confuse food allergy and food intolerance because some of the symptoms and trigger foods are the same. The main difference is that food intolerances do not involve the body’s immune system. Food intolerance reactions can be caused by:

• Food additives
• Naturally occurring chemicals in food
• Problems with digesting natural sugars e.g. lactose and fructose

Reactions or symptoms of food intolerance are often delayed and may occur a few hours (up to 48 hours) after consuming the trigger food.

For example, when someone has lactose intolerance, their body does not produce enough of the enzyme “lactase” to be able to break down and absorb lactose. After having milk or milk products, people with lactose intolerance can experience symptoms such as bloating, wind, nausea, and diarrhea.

Food chemical or additive intolerances share similar symptoms such as runny nose, sinus congestion, headaches/migraines, fatigue, eczema, hives, and mouth ulcers.

In summary: Food intolerances are much slower to cause a reaction and are not life threatening. If you have a particular food intolerance, it is likely you will not need to stop eating that food completely. Instead, you may try lowering your intake to an amount that no longer causes symptoms.

Coeliac disease

You may be wondering where coeliac disease fits into this picture.

Coeliac disease is not a food allergy or food intolerance; it’s an auto-immune condition. In coeliac disease, the immune system reacts differently to gluten, causing inflammation and damage to the small intestine. This damage can affect how our body absorbs nutrients from food, leading to vitamin and mineral deficiencies such as iron deficiency. A strict and lifelong gluten free diet is currently the only treatment for coeliac disease.

Gluten is a protein found in:

• Wheat
• Rye
• Barley
• Oats – these contain a slightly different protein that is like gluten therefore some people with coeliac disease have a reaction to oats. Coeliac Australia recommends people with coeliac disease avoid oats.

Symptoms of coeliac disease may include one or more of the following:

• Diarrhea and/or constipation
• Losing weight without trying
• Fatigue
• Bloating or stomach cramps
• Low iron levels
• Unstable blood glucose levels

Coeliac disease and type 1 diabetes are both auto-immune conditions. It’s estimated that 5% of people living with type 1 diabetes may have coeliac disease and many people with coeliac disease do not experience any symptoms. This makes it important to screen for the condition.

For personalised nutrition advice, we recommend seeking support from an Accredited Practising Dietitian (APD). If you would like to make a booking to see a dietitian, you can book online at the Diabetes Victoria Clinic, or please call 1300 153 123.

For more general advice and enquiries, contact NDSS Helpline on 1800 637 700.