• Written by Dwan Price, Molecular Biologist and Postdoc @ Deakin AIRwatch pollen monitoring system., Deakin University
The humble peanut. Tasty for most, treacherous for some. Dr Dwan Price, Author provided

Food allergens are the scourge of the modern school lunchbox. Many foods contain proteins that can set off an oversized immune reaction and one of the fiercest is the humble peanut.

Around 3% of children in Australia have a peanut allergy, and only 1 in 5 of them can expect to outgrow it. For these unlucky people, even trace amounts of peanut can trigger a fatal allergic reaction.

But what sets the peanut apart from other nuts? Why is it so good at being an allergen?

To answer this, we have to explore the pathway from allergen to allergy, and just what it is about an allergen that triggers a response from the immune system.


Read more: What are allergies and why are we getting more of them?


How food gets to the immune system

Before coming into contact with the immune system, an allergen in food needs to overcome a series of obstacles. First it needs to pass through the food manufacturing process, and then survive the chemicals and enzymes of the human gut, as well as cross the physical barrier of the intestinal lining.

After achieving all of this, the allergen must still have the identifying features that trigger the immune system to respond.

Many food allergens successfully achieve this, some better than others. This helps us to understand why some food allergies are worse than others.

The most potent allergens – like peanuts – have many characteristics that successfully allow them to overcome these challenges, while other nuts display these traits to a lesser extent.

Strength in numbers

The first characteristic many allergenic foods have, especially peanuts, is strength in numbers. Both tree nuts and peanuts contain multiple different allergens. At last count, cashews contain three allergens, almonds have five, walnuts and hazelnuts have 11 each and peanuts are loaded with no less than 17.

Each allergen has a unique shape, so the immune system recognises each one differently. The more allergens contained in a single food, the higher the potency. Additionally, many of these allergens also have numerous binding sites for both antibodies and specialised immune cells, further increasing their potency.

Stronger through scorching

The first hurdle for a food allergen is the food manufacturing process. Many nuts are roasted prior to consumption. For most foods, heating changes the structure of proteins in a way that destroys the parts that trigger an immune response. This makes them far less potent as allergens.

This is not the case for many tree nuts: allergens in almonds, cashews and hazelnuts survived roasting with no loss of potency.

And for the major peanut allergens, it’s even worse. Roasting actually makes them more potent.


Read more: Can I prevent food allergies in my kids?


The gauntlet of the gut

From here, the allergen will have to survive destruction by both stomach acid and digestive enzymes within the human gut. Many nut allergens have the ability to evade digestion to some degree.

Some simply have a robust structure, but peanut allergens actively inhibit some of the digestive enzymes of the gut. This helps them safely reach the small intestine, where the allergens then need to cross the gut lining to have contact with the immune system.

This is where peanut allergens really stand apart from most other allergens. They have the ability to cross the intestinal cells that make up the gut lining. Given their relative sizes, this is like a bus squeezing itself through a cat flap.

Peanut allergens accomplish this remarkable feat by altering the bonds that hold the gut cells together. They can also cross the lining by hijacking the gut’s own ability to move substances. Once across, the allergens will gain access to the immune system, and from there an allergic response is triggered.

Peanut allergens attack the bonds that hold intestinal cells together. Dr Dwan Price, Author provided

The combination of multiple allergens, numerous immune binding sites, heat stability, digestion stability, enzyme blocking, and the effect on the gut lining makes peanut a truly nasty nut.

Where to from here?

This leaves us with a nagging question: if peanuts are so potent, why doesn’t everyone develop a peanut allergy? We still don’t know.

Recently, a potential vaccine developed by researchers from the University of South Australia has shown promise in reprogramming the immune system of mice and blood taken from people with peanut allergy. Will this translate to a potential treatment for peanut allergy? We will have to wait and see.

For now, the more we learn about the action of allergens, and the more we understand their effects on our body, the more we can develop new ways to stop them. And eventually, we might outsmart these clever nuts for good.

Dr Dwan Price was supported by an Australian Postgraduate Award from the federal government.

Authors: Dwan Price, Molecular Biologist and Postdoc @ Deakin AIRwatch pollen monitoring system., Deakin University

Read more http://theconversation.com/tough-nuts-why-peanuts-trigger-such-powerful-allergic-reactions-127120

All You Need to Know About Trenchless Technology

For many years, the traditional sewerage lines and pipe developments were not enough due to the long wait and cracking. The traditional sewer pipe repairs involved cracking the earth to find the par...

News Company - avatar News Company

Before we rush to rebuild after fires, we need to think about where and how

A primary school in East Gippsland was burnt down in the current bushfire crisis. While Premier Daniel Andrews immediately committed to rebuilding the school as it was, media reported the local CFA ca...

Mark Maund, PhD Candidate, School of Architecture and Built Environment, University of Newcastle - avatar Mark Maund, PhD Candidate, School of Architecture and Built Environment, University of Newcastle

Australian sea lions are declining. Using drones to check their health can help us understand why

Australian sea lions (Neophoca cinerea) are one of the rarest pinnipeds in the world and they are declining. Jarrod Hodgson, CC BY-NDAustralian sea lions are in trouble. Their population has never rec...

Jarrod Hodgson, PhD Candidate, University of Adelaide - avatar Jarrod Hodgson, PhD Candidate, University of Adelaide

With costs approaching $100 billion, the fires are Australia's costliest natural disaster

It’s hard to estimate the eventual economic cost of Australia’s 2019-20 megafires, partly because they are still underway, and partly because it is hard to know the cost to attribute to de...

Paul Read, Climate Criminologist & Senior Instructor/Lecturer, Faculty of Medicine, Monash University - avatar Paul Read, Climate Criminologist & Senior Instructor/Lecturer, Faculty of Medicine, Monash University

In cases of cardiac arrest, time is everything. Community responders can save lives

Cardiac arrest can occur with little or no warning in people who were previously healthy, including young people. From shutterstock.comEach year more than 24,000 Australians experience a sudden cardia...

Bill Lord, Adjunct Associate Professor, Monash University - avatar Bill Lord, Adjunct Associate Professor, Monash University

So the government gave sports grants to marginal seats. What happens now?

When Australians pay their income tax, they assume the money is going to areas of the community that need it, rather than being used by the government to shore up votes for the next election. This is...

Maria O'Sullivan, Senior Lecturer, Faculty of Law, and Deputy Director, Castan Centre for Human Rights Law, Monash University - avatar Maria O'Sullivan, Senior Lecturer, Faculty of Law, and Deputy Director, Castan Centre for Human Rights Law, Monash University

The Olympics have always been a platform for protest. Banning hand gestures and kneeling ignores their history

It is the year of the Tokyo Olympics, and the International Olympic Committee was quickly out of the blocks with new guidelines regarding athlete protests. The IOC is worried the biggest stories of...

David Rowe, Emeritus Professor of Cultural Research, Institute for Culture and Society, Western Sydney University - avatar David Rowe, Emeritus Professor of Cultural Research, Institute for Culture and Society, Western Sydney University

Where Can You Get Weed By Ordering It Online?

Nowadays, everyone wants to get their hands on some weed. Marijuana has become legalized in a lot of countries worldwide. People wait in lines for days to buy some. You couldn’t have imagined that...

News Company - avatar News Company

Hidden women of history: Catherine Hay Thomson, the Australian undercover journalist who went inside asylums and hospitals

Catherine Hay Thomson went undercover as an assistant nurse for her series on conditions at Melbourne Hospital. A. J. Campbell Collection/National Library of AustraliaIn this series, we look at under...

Kerrie Davies, Lecturer, School of the Arts & Media, UNSW - avatar Kerrie Davies, Lecturer, School of the Arts & Media, UNSW

Sick and Tired of Your Dead End Job? Try Teaching!

Tired of the same old grind at the office? Want an opportunity to impact lives both in your community and around the world? Do you love to travel and have new experiences? Teaching English is the perfect job for you! All you need is a willingness to ...

News Company - avatar News Company

The Impact of an Aging Population in Australia

There’s an issue on the horizon that Australia needs to prepare for. The portion of elderly citizens that make up the country’s overall population is increasing, and we might not have the infrastructure in place to support this. Australians h...

News Company - avatar News Company