Food allergies on the rise
The dietary problem is a growing drawback to modern life, writes
More and more Kiwis are developing food allergies at a time when the country’s fascination with food is soaring.
It’s a combination that can make social and work occasions awkward and embarrassing, says Allergy New Zealand adviser and former CEO, Penny Jorgensen.
Jorgensen says while there is more general awareness now about food allergies, what is often underestimated is how much of a daily burden it is to sufferers and parents of children with allergies. ‘‘It’s one of these hidden disabilities, really. People don’t realise how much impact it has on life for people with the condition.
‘‘The only way to manage the food allergy is to avoid the food concerned. But food is part of our everyday life and it is involved in a social sense and recreational and the work place. It is just part of the fabric of our life.’’
Having to avoid food everyone else is eating takes a toll. If parents get it wrong they could be responsible for their children being very sick or even possibly dying. ‘‘So it is a really challenging condition to manage.’’
Studies indicate the number of people affected is growing. It’s a hard condition to measure but one measure that can be used is to look at the extreme end – hospital admissions as a result of reactions to food allergies. A study published last year by Auckland University’s School of Population Health looked at national admissions from 2002-2011. It found a 1.7 fold increase in food-triggered anaphylaxis in people aged from 15 over the decade. Jorgensen says it’s believed up to 10 per cent of children under aged 5 are likely to be affected.
Why it happens
A lot of investigations are going on into how food allergies occur and why it’s more prevalent now.
Jorgensen says in general the cause is thought to be because of a complex interaction between genetics (a predisposition to develop the allergy) and our changing environment and lifestyle. You could regard allergies as a side-effect of Westernisation. Factors being researched include a reduction in our microbial diversity.
This is the former hygiene theory – now referred to as the microbial hypothesis. We have millions of microbes, in our gut in particular, and they play a role in how our immune system is set up. Because we have become so clean – getting rid of good bacteria as well as bad bacteria – the idea is we have messed things up and the diversity is wrong. This leads the immune system to react to food and other substances that are otherwise quite harmless.
Another theory is the lower levels of vitamin D we get from the sun now thanks to our indoor lives is also having an impact on how the immune systems are set up and programmed. Another factor might be how parents were previously advised to delay giving children high-risk allergenic foods like eggs, milk and peanuts.
That could be backfiring by making older children more susceptible. Recommendations are now going the other way. Diet is another possibility. The obesity epidemic, the rise in sugar consumption and in eating processed foods might all play a part.
What happens
Jorgensen says the first time someone eats a new food the body will take a look at it.
‘‘The immune system will decide whether it is safe or not.
‘‘If it is safe, nothing happens. But the immune system might look at it and say ‘this is a threat, I’m really worried about this’ and it sets up IGE antibodies. The second time the child encounters that food, the immune system again either decides to let it go or it launches an allergic reaction. Reactions happen very quickly, usually within minutes,’’ Jorgensen says.
Parents might notice symptoms like hives, swelling around the face, or sudden breathing difficulties. With breathing problems, call an ambulance.
If it’s just facial swelling and hives, she says see a doctor and start down the route of a diagnosis. Usually a diagnosis is made on clinical history – the symptoms, the timing and the most likely culprit that was eaten.
Common food allergies
Most food allergy reactions come after food has been eaten. Any type of food can trigger one, but most reactions are caused by egg, cow’s milk (dairy), peanuts, tree nuts (cashews, almonds, Brazil nuts), soy, wheat, seeds, fish and shellfish.
Most common triggers in infants are egg and dairy, while nuts and seafood lead the figures in older children, teens and adults.
Prevention advice for infants
The Australasian Society of Clinical Immunology and Allergy recommends at about 6 months, and when they are ready, infants should be introduced to a variety of solid foods. Parents should start with iron rich foods and while breastfeeding continues.
The society says all infants should be given allergenic solid foods, including peanut butter, cooked egg, dairy and wheat products in the first year, and this includes infants at high risk of allergy.