D^re Chantal Lemire, pediatric allergist-immunologist at the Center hospitalier universitaire de Sherbrooke. Several factors are reported in the scientific literature. THE’hygienist hypothesis gains in credibility, but no consensus. We understand this hypothesis better if we imagine a scale: on the one hand, causing infections and, on the other, having allergies. Before, many children died from infections at an early age. Today, bacterial infections are treated with antibiotics, children are vaccinated. Families are smaller, so children are less exposed to infectious agents. Our more sanitized living environment means we have fewer infections… This leaves more room for our immune system to develop allergies. It is therefore important to make judicious use of antibiotics. This is a complex question and we do not yet have all the answers.

D^r Paul Lépine, general practitioner at the Passion Santé clinic in Quebec City. The increase in air pollution seems to me to be the main factor. The more polluted the cities, the more people there are with respiratory allergies. The particles of pollutants may make the mucous membranes of the respiratory tract more fragile and sensitive. About the pollution of water and soil, and therefore of our food, we have much less data. I believe that allergies are first and foremost a problem with the barrier, that is, with the mucous membranes that allow substances that should not enter the body to pass through. There is no indication that you have a poorer immune system than before. However, it is evident that our environment is much more polluted than it used to be.

D^r Normand Dubé, allergist-immunologist at the Center hospitalier universitaire de Montréal. Increasing exposure to pollutants appears to be one of the determining factors. Some studies in vitro (on cells in the laboratory) have already shown that diesel particles that emanate from motor vehicles contribute to allergic reactions. This could impact not only respiratory allergies, but also food and skin allergies. Is this effect also observed in the individual? It seems more and more likely. Indeed, other more recent studies suggest that, more generally, atmospheric pollutants could contribute to allergic reactions and more particularly to the onset of asthma through direct effects on the expression of the genetic code of individuals ( “epigenetic” effect). This is still a hypothesis.

Nathalie Jobin, nutritionist at Extenso. We are in contact with a growing number of allergens. We are consuming a much greater variety of substances, whether natural or chemical, than 2 or 3 generations ago. The increasingly common peanut allergy is a good example. In the grocery store, so many processed foods contain it, even in trace amounts, that the number of people who may be allergic to it is increasing.

Gilles Parent, naturopath. In the clinic, I meet more and more people withdelayed food allergies, that is, symptoms will appear 4 to 48 hours after consuming a food. These delayed allergies can manifest themselves differently from other “typical” food allergies: fatigue, migraine, sinusitis, sore throat, bronchitis, hyperactivity, otitis, alopecia areata, psoriasis, diarrhea, irritable bowel, gastritis, redness, skin rashes, etc. But they can also be related with symptoms of allergic rhinitis, asthma and eczema. It is often thought that the allergy is limited to hives, asthma or anaphylactic shock. Think again, it manifests in over 100 different ways! In conventional medicine, allergies are considered to be a problem with the over-reacting immune system. This overreaction occurs because too many allergens pass through the mucous membranes. More and more people have digestive mucous membranes that are too permeable for several reasons. I am thinking of the excessive use of antibiotics and anti-inflammatories, of stress, which is even more present nowadays, and of the consumption of refined, poorly nutritious foods.

D^r Paul Lépine. Everyone can do their little to pollute less. However, on a collective level, the solutions are immense and underexploited. Otherwise, prevention takes place mainly in the infant. Infants who are exposed to allergenic food proteins early on, such as peanuts, fish, etc., have been shown to have more allergies than those exposed to them later. Breast milk is still the best way to prevent allergies, but for women who are not breastfeeding, formulas made with hydrolyzed protein reduce the risk of developing atopic (allergic) eczema. Like breast milk, they contain only very small proteins. The impact on reducing other types of allergies is still theoretical, but possible. The taking of probiotics by the mother at the end of pregnancy and then by the child during the first 6 months of life is also associated with a reduced risk of eczema and markers of inflammation in the blood.

Nathalie Jobin, nutritionist. For all children, it is important to respect the schedule for introducing complementary foods, and even more so for children at risk of allergies. Staying on schedule allows the immune and digestive systems to mature before they come into contact with certain foods. When it comes to major allergenic foods, like eggs, peanuts and seafood, experts could not prove that delaying their introduction prevents food allergies. I recommend that parents get information from a doctor or a nutritionist. In addition, exclusive breastfeeding is strongly recommended during the first 6 months. Protection would be even better when the child can benefit from breast milk until the age of 1 year.

D^r Normand Dubé. In Europe and North America, the use of probiotics for prevention has been explored. It was given to young children to see if certain allergies could be prevented. The results indicate some preventive effect, but only against eczema. Currently, we are exploring the potentially beneficial effect of prebiotics. Also, you should know that allergies are not prevented by trying to avoid allergens and infections in a “sanitized” environment. On the contrary, being exposed to allergens and infections would contribute to a healthy maturation of the immune system.

Gilles Parent, naturopath. We must ensure that we have complete digestion, regardless of our age. Dietary protein that is not broken down during digestion is likely to pass through the intestinal lining. If this happens, the immune system will recognize this protein as foreign and enemy, and will cause an allergic reaction to defend the body. To prevent this type of reaction, care must be taken to keep the lining of the intestines healthy. In this regard, it is important not to overuse antibiotics, as they destroy the flora. In addition, we must nourish the flora by consuming enough dietary fiber. Then, you have to make sure you have a diet rich in fruits and vegetables, proteins and fatty acids in order to obtain all the nutrients that allow the integrity of the mucous membranes to be maintained. And don’t forget to chew well! This stimulates the production of enzymes necessary for digestion.

D^re Chantal Lemire. The first thing to do is to avoid smoking. It is repeated often, but irritation of the lining of the nose and lungs contributes to respiratory problems, including allergies. I also advocate breastfeeding, even for families whose children are not particularly at risk of allergies. Breast milk is the best food for the baby.

D^r Normand Dubé. If mild to moderate symptoms of allergic rhinitis, for example, are not taken care of, they can get worse and lead to chronic sinusitis problems. Do not hesitate to take medication, because in addition to improving the quality of life, they reduce the risk of aggravation. Mild symptoms of rhinitis can persist longer, and sometimes even lead to asthma. Now we think of the nose and the bronchi as a single organ. Thus, the treatment of one does not go without the other. This represents the so-called unified approach to the treatment of allergies involving the respiratory tract as a whole.

Gilles Parent, naturopath. Delayed food allergies can cause an inflammatory process and cause, in part, autoimmune diseases (Editor’s note: for example, rheumatoid arthritis, multiple sclerosis, psoriasis, lupus, Crohn’s disease, etc. ). This is still a very controversial issue. But, a few hundred scientific publications report sometimes dramatic reductions in the symptoms of autoimmune diseases in people who follow a diet low in allergens or hypoallergens. Thus, to know if the autoimmune disease is linked to allergens, we resort to a diet low in allergens adapted to the person. There are also laboratory tests to identify the allergens involved, which can include food additives, dyes or molds. Once discovered, allergens are simply eliminated from the diet. However, these tests are expensive.

D^r Paul Lépine. Personally, I don’t think allergies can cause autoimmune diseases. I haven’t seen anything convincing about it. Can delayed food allergies manifest as non-digestive symptoms? Probably, but there is a lack of data to confirm this. Note that the hypoallergenic diet is so difficult to maintain that it certainly has a very powerful placebo effect. It has several negative impacts on social life, family, mood, because eating is an important human and social act. In addition, when you stop this diet, the problems return. Well supervised and supervised, we can try it, but I do not recommend it in general. The good news: Several studies suggest that people with allergies have a lower risk of developing cancer one day.

D^re Chantal Lemire. The main consequence is what is called “atopic walking”. A newborn baby who has a lot of eczema is then more likely to have food allergies, asthma, allergic rhinitis and dust mite allergies. In adulthood, some of these conditions may go away.