A study published in JAMA-Pedriatics, in 2013 does show that we do appear to have worse allergies here in westernized industrialized countries compared to other countries, not just food allergies, allergic rhinitis, hay fever, eczema, and asthma as well. When looking at kids that are born elsewhere compared to kids born in the US. They find that kids born in other countries tend to have less allergies, but that gap narrows the longer they live in the US, meaning those that lived here for more than a decade were much more likely to have allergies compared to those who lived here for only two.
Another study published by the Public Library of Science in 2014 showed that children of immigrants tend to have more allergies than the immigrants themselves. Clinically it is pretty common to see people from other countries come to the US and their kids have allergies but the parents have never seen allergies before, nor have the grandparents. However, in general, allergies are rising across the board, across all industrialized countries, they just might manifest differently in other countries. For example, if you look at the worst food allergies in Western countries like Australia, Canada, and New Zealand and the US, you'll see that tree nuts and
peanuts are the highest on the list. Egg and cow milk is higher in Latin America. European countries follow us with tree-nuts and peanuts, but Asian countries tend to have more allergies with shellfish and much less peanut allergy compared to shellfish allergy compared to us.
One possible explanation is vitamin D deficiency, that the migration patterns are affecting how kids absorb vitamin D. The second possibility is an increase in eczema and more of the food allergies are coming contact with the skin. The environment in which an allergen comes in contact does change how it reacts to the allergen. So, eating something is more likely to build tolerance to it. And if it comes into contact through a skin barrier, you're more likely to become allergic. Another explanation is that we have more ultra processed foods in our diet that might be causing inflammation and allowing proteins to pass through the gut barrier that wouldn't have passed through intact. And therefore, we develop allergies to the food. We also could develop an allergy via inhaled particles. So you can become allergic to shrimp through dust mites or cockroach allergy because it has a similar protein. Or you can become allergic to different foods through pollen allergies. So as we have to reach climate change CO2 levels, the pollen exposure is longer, you're more looking to develop allergy to the pollen that allergy can translate to a food allergy. Lastly an explanation is that our good bacteria gets wiped out by certain things we doing to clean out the bad bacteria. With our gut bacteria compromised, we are more likely exposed to allergens.
So to decrease risk of food allergies we can decrease risk of exposure by these mechanisms. Example breastmilk has HMO that is food for gut bacteria and avoiding ultra process foods that damage the gut bacteria. If the child has eczema, try to limit the protein irritant entering through the skin by moisturizing and creating barriers using creams. Lastly is genetics, pollution and other factors that are beyond our control.