Do you have a food intolerance?

Updated June 2022 | 5 min read
Expert contributor Zoe Wilson, accredited practising dietitian and nutritionist
Words by Sara Mulcahy

For many Aussies, certain foods can pose problems to our wellbeing. Here’s how to tell if you could have a food intolerance, and steps you might take.

Take a seat in a café these days and chances are the menu will come decorated with little symbols to tell us which dishes are vegan and vegetarian, but also gluten-free, dairy-free, lactose-free, nut-free… and the list goes on.

According to a recent report in the Medical Journal of Australia, 1 in 4 adults actively avoid gluten. So have we become more sensitive to certain foods, or are we just more particular about what we eat? The truth is, it’s probably a combination of both. For some it’s a lifestyle choice, but for others, certain foods can cause issues for our wellbeing.

Zoe Wilson, accredited practising dietitian and nutritionist, says: “I think food intolerances are on the rise due to our knowledge and awareness of them. People used to just ‘deal with’ symptoms or avoid foods that didn’t ‘sit well’ with them.

“However, now we know more about intolerances, and we talk about them more often, they are being more commonly diagnosed.”

What’s the difference between a food allergy and food intolerance?

They’re often spoken about interchangeably, but a food intolerance is different to an allergy. Allergies are an immune response to a food protein (that’s a specific component of the food) and the onset of symptoms is usually swift. Symptoms of a food allergy can range from mild to severe and can include itchy eyes, rashes and hives, diarrhoea and vomiting, swelling of the face, lips and eyes and, in extreme cases, anaphylaxis.

Food intolerance is an adverse reaction to a particular food, but doesn’t involve the immune system. The symptoms can be unpleasant, and in some cases severe, but are generally not life-threatening.

How do you know if you have a food intolerance?

“Common signs and symptoms of a food intolerance include gut symptoms like nausea or vomiting, stomach pain or cramps, gas or bloating, diarrhoea or constipation and heartburn,” says Zoe. “Also common are more ‘vague’ symptoms like fatigue or mood changes.”

Symptoms typically happen a fair while (up to 72 hours) after the food has been consumed. Most intolerances can’t be diagnosed by blood tests and are usually confirmed by elimination diets with the help of a health professional, like an accredited dietitian.

“The range of symptoms and the variation in severity from person to person can make it difficult to get a diagnosis without professional help,” says Zoe.

What are the most common food intolerances?

There are 9 common foods – peanuts, tree nuts, cow’s milk, eggs, wheat, soy, sesame, fish and shellfish – that are responsible for 90% of all allergic reactions, but there are more than 170 foods that can cause food intolerance.

The most common include milk and lactose (the sugar in milk), gluten, wheat, food preservatives and caffeine. Other triggers include sulphites – a preservative commonly found in wine and dried fruits – additives like artificial colours, and FODMAPs (a group of sugars that aren’t fully digested in our intestines), which are found in foods ranging from wheat and onions to milk and apples.

“Intolerances to FODMAPs are the most common that I see,” says Zoe. “These different sugars (naturally and added) are commonly found across all food groups. When they aren’t absorbed properly by the gut, they can then trigger IBS-like (irritable bowel syndrome) symptoms.”

“It takes time to figure out which group or groups someone is intolerant to,” she adds. “Often people think it may be one group (for example, dairy or gluten) but it’s entirely another. This is why it’s important to see an accredited practising dietitian with experience in food intolerance, who can help you figure out the culprits."

Can you suddenly develop a food intolerance?

Say you’ve happily enjoyed milkshakes or pasta for your entire life up until now, then you start to find that certain foods are having a disruptive effect on your digestion. Are you imagining it?

“You can definitely develop an intolerance later in life,” says Zoe. “As with your immune system, your digestive system can change as you age or after an event like an illness. Lactose intolerance is a great example because as you age, you produce less of the enzyme responsible for digesting lactose.”

Zoe adds that food intolerances can vary from person to person. “Someone may be intolerant to lactose found in dairy and only be able to tolerate a small amount of yoghurt or soft cheese or none at all, whereas the next person might only experience symptoms with a glass of milk and tolerate yoghurt and cheese just fine,” she explains.

What to do if you think you might have a food intolerance

If you suspect you have a food intolerance, try these 3 things to help with a diagnosis further down the track.

1. Start keeping a note of rashes, asthma, hay fever, headaches, vomiting and diarrhoea and any other unexplained symptoms. Think back and try to pinpoint other similar events in your medical history.
2. Consult your GP who may refer you to an allergist, who can use blood and skin tests to help determine (or rule out) what you’re allergic to.
3. If you have no specific allergens, your doctor may ask you to keep a food diary to identify possible problem foods.

Food intolerance: DIY diagnosis

According to UK research, there’s a worrying trend of self-diagnosis for food intolerance, with more than a third of those who claim to have an intolerance admitting to never having consulted a healthcare professional about it. Many people put themselves and their family members on limited and expensive diets because of information they hear second-hand or read online.

Adopting a restricted diet that eliminates certain foods can deprive your body of essential nutrients and be detrimental to your health. Cutting out dairy, for example, may result in poor bone health, high blood pressure and a higher risk of developing diabetes.

“Seek help from your GP and an accredited practising dietitian with experience in food intolerances,” says Zoe. “They’ll be able to help figure out what you may be intolerant to and find a plan for you moving forward.”

Find an accredited practising dietitian on the Dietitians Australia website.

A GP at your fingertips

We know it can be hard to manage your health in a convenient way. Our partnership with GP2U, an online video GP service, makes it easier for eligible members to access telehealth services. All HCF members with health cover can access a standard GP consultation (up to 10 minutes) for a fee of $50. See hcf.com.au/gp2u for more information.