Why is your baby vomiting industrial milk? Why can’t your child step outside in May without having tears in their eyes? And why does your daughter get short of breath as soon as she sleeps in a country house? Today, respiratory and food allergies affect many children…. And more and more. The causes of these allergic diseases seem multiple and complex. It therefore seems essential to better understand them in order to prevent their explosion.
Allergies increased from 3.8% to 30% of the world’s population in fifty years
There is normally no reason why a human cannot tolerate grasses or peanuts from birth. It is an excessive immune reaction that explains that the nose runs, that the eyes redden, that he sneezes, swells, scratches… “Allergies are in 4th place among chronic diseases according to the World Health Organization, introduces Karine Adel-Patient, researcher at the Public Research Institute working for coherent and sustainable development of agriculture, food and the environment (Inrae). And the WHO predicts that 50% of the world’s population will suffer from allergies in 2050.” Because these pathologies, respiratory or food, have been constantly increasing for thirty years. The WHO estimates that 30% of the world’s population is affected by an allergic disease today, compared to 3.8% in 1968.
“Allergies are more and more frequent and severe in children”
In France, the number of people suffering from an allergy has doubled in twenty years, according to associations. Without sparing the children. Even if it is complicated to compare surveys that do not always have the same subject of study – for example a single food or a single pollen – or the same population studied, several international and French studies have cause for alarm. The Elfe study, which follows 15,000 French children born in 2011, reveals that 6% of them have developed a food allergy, and among them, 20% have several allergies. “Allergies are more and more frequent and severe in children, says Karine Adel-Patient. asthma [80 % des asthmes sont allergiques] affects 4 million French people, a third of whom are children. Similarly, 6 to 8% of children suffer from food allergies… compared to 2 to 4% of adults. »
A concern confirmed by Madeleine Epstein, allergist in Paris and vice-president of the union of allergists (Syfal). “Objectively, there are more and more allergic children. When I became an allergist in the 1980s, we hardly talked about food allergies. Moreover, it was with children that we discovered allergies to peanuts, milk… Today, the most common food allergic reactions in them concern peanuts, nuts, eggs. and milk. “With a significant impact on their daily lives. “Allergies are the leading cause of school absenteeism, points out Karine Adel-Patient. A child allergic to milk will not be able to participate in birthday parties. »
Possible explanations for this increase in allergies
Is it the omnipresence of plastic in our environment? Chemical compounds in baby bottles? Industrial food? Clothes ? Air pollution ? The causes remain very mysterious. “It’s multifactorial, warns the allergist. The immune system is dysfunctional. Who orders it? The microbiota. However, changes in diet and environment influence it. We also know that the use of antibiotics modifies it, but there are more allergies in children who have received a lot of small antibiotics. »
A track also leads to global warming. Plants and trees grow where the population has never been exposed to this kind of pollen. “Pollution acts on pollens by making them more allergenic, and on the respiratory mucous membranes by making them more fragile. Moreover, it can modify the genome and make the propensity to be allergic hereditary. It works in all directions, it’s great! “, quips Dr. Madeleine Epstein.
This explains why there are more and more allergic children, it is also that the genetic component is important. “In the general population, a child has between 5 and 10% risk of developing an allergy, but between 30 and 40% if one of his parents is allergic, and up to 60% if both parents are,” continues Karine Adel-Patient. Logically, if more and more adults develop allergies and become parents, the proportion of allergic children climbs.
How to determine the factors of these allergies and improve prevention?
To go further and understand the triggering factors, Karine Adel-Patient’s team at Inrae has launched a research project on the link between food and allergies in childhood. For five years and thanks to the support of the Foundation for Medical Research (FRM), they have been trying to determine which chemical contaminants, ingested by the mother during pregnancy and breastfeeding, could be responsible. The researchers rely on two major French epidemiological studies: Elfe, which we have already mentioned, and Eden, which focuses on the determinants of child development and health. “They follow mothers during pregnancy to find out about their diet, their way of life,” explains the researcher. Then we take samples of milk, hair, urine at the maternity ward. Then, their children are followed for ten or twenty years, in particular to see if they develop allergies. Then we will cross these data with those of the National Food Safety Agency (Anses), which has published levels of contamination for 400 foods covering 90% of the average French diet. »
Additional approach: the team is interested in meconium, the baby’s first stool. “They accumulate during the last six months of pregnancy. History to examine what the fetus has ingested via the placenta. Finally, the researchers test certain contaminants on mice to see if their offspring develop allergies. The goal? “We hope to be able to highlight specific dangerous contaminants and help implement a prevention policy to curb the allergy epidemic,” concludes Karine Adel-Patient. In the meantime, what can pregnant mothers do? The researcher advises them “to eat diversified, seasonal fruits and vegetables, as natural as possible, and to avoid everything that is processed and packaged. With the hope of having much more specific recommendations within ten years.