THE food allergy spike

Food intolerance and allergy can develop at any age – but why is it on the rise and which foods are mostly to blame?

Remember when having friends around for dinner simply involved you cooking up a tasty dish? Now, as you cater to all the food issues of your guests, it can feel as if you’re moonlighting as a dietitian. One in six Aussies now avoid dairy foods such as milk, cheese and yoghurt, research from the CSIRO and University of Adelaide shows. The same study found that one in 10 Aussies have cut out foods containing wheat in the hope that avoiding gluten will help relieve health issues such as bloating, wind, tummy cramps and tiredness.

Why are food allergies on the rise? Doctors don’t really know. What we do know: you can figure out if you have one or if you’re suffering from something else.

Adult onset food allergy

You’re dining al fresco and enjoying a nice drop of white with a large plate of prawns. All of a sudden your throat feels a little itchy. You eat a few more prawns and now your throat starts to feel tight. Suddenly you connect the dots – realising you’re having an adverse reaction. This is the face of adult onset food allergy. Though we think of this kind of allergy as a condition that begins in childhood, in some people it doesn’t occur until their 30s, 40s, 50s or beyond. American research shows that almost half of adults diagnosed with food allergy, developed their problem in adulthood. Australian research has also shown a spike in hospital admissions for adult food reactions.

Shellfish is the most common cause of adult onset food allergy but other triggers include egg, cow’s milk, peanut, tree nuts, seafood, sesame, soy, fish and wheat. If you’re super sensitive, your immune system can go rogue and respond as though the proteins in these foods are invaders. To protect you, your body pumps out antibodies called immunoglobulin E (IgE) - which can be measured in the blood to diagnose food allergy. Like little soldiers on the front line, antibodies attach to organs such as your gastrointestinal tract, skin and lungs. Next time the problem food is eaten they trigger a ‘red alert’ response. Your body over-reacts, trying to expel the food quickly and this causes symptoms such as vomiting and skin reactions.

The dangers of food allergies

True food allergy is rare –affecting just 2 per cent of us, says the Royal Prince Alfred Hospital (RPA) Food Allergy Unit. Mild allergic reactions may cause eczema or hives. But in severe cases it can cause anaphylaxis. “Anaphylaxis can lead to nausea and vomiting, hives and welts on the skin and swelling of the face, mouth, lips and eyes,” explains Professor Rob Loblay, immunologist and director of the Allergy Unit at RPA. “It can cause serious breathing issues. It can also trigger anaphylactic shock – a sudden drop in blood pressure causing dizziness, loss of consciousness and a lack of blood flow to the brain.” People at risk of this need to carry a portable injection of adrenaline which should be given as soon as possible.

Though some people can grow out of their food allergy, this is less likely with peanuts, tree nuts, seeds and seafoods which tend to cause lifelong food reactions. “If you suspect a food allergy it’s important to visit an allergy specialist and be tested,” says Loblay.

Is it a food intolerance or an allergy?

When a friend or colleague cuts out food like bread to see if they have a food ‘allergy’, what they really mean is that they’re looking for a ‘food intolerance’, which is more common than food allergy but not life threatening.

One in 10 of us suffers symptoms such as tummy bloating, skin rashes and exhaustion that are caused by a reaction to compounds in food – whether naturally occurring (like lactose in milk) or food additives (like MSG) says the Dietitians Association of Australia (DAA). “Some people may even feel vaguely unwell with flu-like aches and pains or become unusually tired, run-down or moody,” Loblay says.

Studies show women are more affected by food intolerance than men. It may be due to hormonal shifts that change a woman’s responses to food chemicals, particularly when she goes on the contraceptive pill, becomes pregnant or reaches perimenopause or menopause. Other triggers (such as a sudden change of diet, adverse drug reaction or a viral infection like glandular fever) may also bring on food intolerance for the first time.

Having a food intolerance doesn’t mean the problem food needs to be completely off limits – you may still be able to tolerate it in small doses. “For example, a person with lactose intolerance may be able to enjoy small quantities of milk with no reaction or may eat yoghurt or hard cheese which contain no lactose,” says Aloysa Hourigan, spokesperson for Nutrition Australia.

When it’s wrong to cut out a food

“If someone suspects they have a food intolerance their instinct may be right, but often they are incriminating the wrong foods,” warns Loblay.

Wheat and dairy get the most bad press, and yet research shows they cause far fewer food intolerance issues than honey, broccoli, oranges and canned tuna, which are high in compounds called salicylates and amines (see opposite page).

The danger with self-diagnosing is that you may mistakenly cut out whole food groups when only one single element is the cause. And inadvertently this can lead to nutritional deficiencies, says Hourigan. “For example, if you stop eating dairy products and don’t replace your calcium intake with a high intake of fish like salmon and calcium fortified rice or soy milk, you could end up increasing your risk of osteoporosis down the track.”

By self-diagnosing incorrectly, you’re also delaying discovery of the real cause. “Issues like bloating or headaches could be caused by other underlying health problems, so it’s always important to have physical symptoms investigated by your GP rather than second-guessing if they are caused by food,” says Hourigan. “Once you have ruled out other causes, if food seems to be the problem, it’s best to see a dietitian or nutritionist for advice and help in diagnosing the foods responsible.”