Did you know you can develop an allergy at any age, to any food, despite having eaten that food without any prior symptoms? While allergies are most common among children (affecting 10% of Kiwi infants, and only 2-4% Kiwi adults), a study of 40,000 US adults found almost half of those living with allergies developed it after the age of 18.
Why only certain people develop allergies remains unclear, so recognising the signs and symptoms of an allergy, including a potentially life-threatening allergy is incredibly important, says Maria Said, CEO of Allergy & Anaphylaxis Australia.
“We simply don’t know what switches an allergy on or off in certain people. The majority of allergy-specific research focuses on allergies in children, so adults and teens can sometimes be left out in the discussion.
“We regularly have adults presenting to us thinking they have developed an allergy out of the blue. Suddenly they cannot eat certain foods, or worse, they’re not actually sure what has caused an anaphylaxis in the first place, and they need help isolating the trigger. We also have a number of adults coming to us saying they have a food allergy, when in fact what they’ve developed sounds like an intolerance. The word allergy is often used when allergy has not been properly diagnosed.”
So what is an allergy?
An allergy occurs when your immune system overreacts to a normally harmless substance, like food, pollen or dust mites and determines that the substance is a threat. This then causes a reaction in your body – usually in the form of hives, swelling or breathing symptoms.
Can I develop an allergy as an adult?
Yes you can. As you age, some researchers suggest that your immune system may weaken naturally, which may be why you’re suddenly struggling with that creamy milkshake or feeling itchy after some grilled fish. Certain events (like pregnancy or illness) that occur during adulthood can also compromise your immune system, which may trigger a reaction to a food that you’ve had no trouble with in the past. Theories suggest limited exposure to allergens as a child can also trigger an allergic response as an adult.
Do I have an intolerance or an allergy?
If your symptoms mainly involve the digestive system (like stomach pain, bloating and gas) a few hours after eating certain foods, this is likely an intolerance. Like your immune system, your digestive system can also be affected as you age which may see you develop an intolerance later in life.
Intolerances can be easily managed as most are dose-dependent and are non life-threatening – find a ‘sweet spot’ that your body can handle and you may still be able to enjoy that food, in moderation of course.
Some intolerances are more common as an adult, like lactose intolerance (up to 70% of the world’s population complain of stomach upset when consuming milk or dairy products) and gluten intolerance.
- Lactose intolerance: Everyone is born with the enzyme lactase, which helps your body digest the lactose in foods. Your body naturally produces less lactase as soon as you’re weaned from milk as a baby. As you get older and your lactase production continues to decline, you may find yourself suddenly struggling with high lactose dairy products like milk, and experience mild to severe symptoms like bloating, wind and diarrhoea if you have too much. While some people will be able to tolerate small levels of lactose, others will find comfort from lactose free milk or options like soy and other dairy alternatives.
- Gluten intolerance: Gluten is a protein found in wheat, wheat varieties like spelt or farro, and is also found in rye, triticale, oats and barley. It gives dough its elasticity and helps it to rise, and it’s also used as a thickener in some processed foods. Unlike coeliac disease (affecting just 1% of the population and means strict avoidance of gluten-containing products) gluten intolerance is often self-diagnosed as there are no tests to determine gluten sensitivity. Many adults report feeling better when they avoid gluten, however, a recent study found only 16% of those who reported a gluten sensitivity actually had reproducible symptoms when they didn’t know if they were given wheat or a placebo. So while adult-onset intolerances to gluten may seem high, the true numbers may be exaggerated.
- Some people may also have a true wheat allergy, which can be life threatening, or live with coeliac disease. These are very different to a wheat intolerance and should be properly diagnosed before whole food groups are avoided.
What are the symptoms of an allergy?
Unlike an intolerance, an allergy
can be serious. Your symptoms
would mainly involve an immune system
response after eating or coming into contact with an allergen. Symptoms will appear quickly – usually within 20 minutes to 2 hours. They may start off mild, but progress rapidly.
The most dangerous reactions (anaphylaxis) involve the respiratory and cardiovascular systems and are extremely serious.
You may notice mild to moderate symptoms
- Swelling of the face and eyes
- Tingling of the mouth
Or, you may notice more severe symptoms (anaphylaxis), including:
- Difficulty breathing
- Swelling or tightness of the throat
- Swelling of the tongue
- Persistent dizziness (children can become pale and floppy)
For adults, the most common reactions are to fish, shellfish, peanut and tree nuts.
What are the risk factors?
Your chances of developing a food allergy as an adult may increase if you’re already allergic to something else in that same allergen family, like pollen. This cross-reactivity is also known as Oral Allergy Syndrome, where certain fruits and veggies may cause symptoms like itching of the mouth, because your immune system ‘sees’ the proteins of the food as similar to the allergenic pollen proteins.
What should I do if I have allergy symptoms?
If you suspect a food allergy, it’s important that you make an appointment with your doctor to have it investigated further, who will then refer you to an allergy specialist for further investigation and diagnosis.
Referral by your GP to an dietitian for those with difficult to manage or multiple food allergies can also help guide you through the process so that you can find the best replacement foods to ensure you are still getting the best nutrition for your body.
Developing an allergy at any age can be scary, but there are plenty of support networks with resources to help you. Visit Allergy New Zealand for further information and support.