The myth of flying peanuts: not so deadly after all

Not quite true. Dan4th Nicholas, CC BY

By the time the Ryanair flight had touched down, four-year-old Fae Platten had been taken away by paramedics and a group of passengers were converging menacingly on a Zimbabwean man they accused of trying to kill her. His crime? He had ignored requests by the air stewardess to refrain from eating nuts on the flight and had opened a packet while sitting four rows behind the girl. The major allergic reaction it triggered nearly killed her.

Fae stopped breathing and was only saved by an EpiPen injection administered by the flight crew. The family knew their daughter had multiple allergies and was extremely sensitive to nuts, so passengers were told three times not to eat nuts on the three-and-a-half-hour plane journey.

The airborne myth

These stories of severe allergies are becoming increasingly common. Food allergy rates in kids have risen significantly, affecting up to 10% of Western kids. Researchers have suggested that in the past decade cases of peanut allergies have doubled or even tripled, according to one US survey, and are becoming apparent in Africa and Asia. We forget that this condition was so incredibly rare that the first ever medical study into acute food allergy was in 1969 – just at the time of the moon landings. Now one in 50 children in the UK and Australia is affected.

1969: time of first medical study into acute food allergy. David Trawin, CC BY-SA

Faced with increasing numbers of young children potentially dropping dead from inhaling nut dust, there has been discussion about banning nuts on flights altogether, and worried parents have lobbied to have nut-free schools not only in California – but also in England. The problem is that this airborne risk is a myth.

Although nut allergy is real and scary for parents and sufferers – it can’t for practical purposes be transmitted through the air enough to cause these severe reactions. Researching the story for my new book, The Diet Myth, I spoke to several of the world’s leading food allergy consultants including Adam Fox, a consultant in paediatric allergy at St Thomas’ Hospital. He and colleagues who have worked for many years testing thousands of children with severe allergic reactions had “never heard of nut vapours causing these severe reactions”. Peanut particles are heavy and although can form dust on surfaces, studies have been unable to detect peanut particles in the air or the key allergens in the air in sufficient amounts to cause a reaction.

They all agreed that the plane incident as it was reported could not have occurred however strong the plane air conditioning or the belief of the parents. Her lips or tongue must have touched something else directly. The timing was unfortunate and the exact trigger still a mystery.

Of mice and mothers

But why are we going through such an epidemic of food allergies in children? A recent study has shed light on this – and our diet is a likely culprit.

Australian researchers used mice sensitive to allergies and asthma and found they could prevent the risk of young pups being allergic depending on what the mother ate in pregnancy. The higher the fibre content and the more food diversity, the lower the rate of subsequent allergies. What was really novel was that gut microbes were crucial to the process. Pregnant mice with the high-fibre diet had a group of microbes that produced an anti-inflammatory chemical called acetate.

When they looked at human pregnancies, a similar association with dietary fibre was seen with the chemicals produced by microbes. The higher the fibre intake, the higher the acetate levels and the less allergy in their children.

These trillions of different bacteria in our lower guts keep us healthy. They do this by feeding off the fibre from rich foods and converting the nutrients to healthy chemicals that suppress our immune systems. So the higher the fibre content and diversity in meals the better the effect on the immune system.

Fear of allergies

Pregnant mothers now are under huge pressure to be healthy - but the advice they get is conflicting. Many with allergic families are told to cut out foods or avoid eating peanuts (there is a common belief that eating peanuts will lead to a peanut allergy in babies later), while others are routinely told to avoid eating French cheese or salamis, raw or undercooked meats because of the risk of very rare infections that other countries don’t worry about.

In this way they anxiously end up on very restrictive diets, lacking diversity and fibre. These diets could be having the opposite effects to those intended as they starve our gut microbes of nutrients and reduce the immune dampening chemicals they naturally produce.

An increasing trend is that many of us think we have food allergies when we don’t. One study found that while 38% of people think they have a food allergy, the real figure is closer to around 1%. This exaggerated fear of allergies means that parents are preventing some children from eating foods such as wheat, nuts, eggs or milk.

Paradoxically, peanut allergy looks like it could be cured by reintroducing tiny amounts of peanuts slowly early in life. Early studies also suggest microbes can help prevent the allergy as introducing probiotics has also helped. Data so far shows non-allergic mothers who eat peanuts are less likely to subsequently have peanut allergic children. And a change of heart may finally be underway after interim guidelines issued by the American Academy of Pediatrics, and based on a peanut trial led by Gideon Lack at King’s College London, suggested that babies at high-risk of developing peanut allergy are protected from peanut allergy at the age of five if they eat peanut frequently, starting within their first 11 months.

So let’s stop banning foods like peanuts and dairy products, and living in hygienic antiseptic bubbles. To extract us from the allergic cycle we are in, we should be encouraging food diversity in our diets from an early age to keep our gut microbes as healthy as possible. We all need to increase consumption of “microbe friendly” foods, a diverse range of fibre-rich and fermented foods including regular nuts and seeds, with less fear about holding back from what children eat.