[QUOTE=spazurek]
The story about our kids’ environment being too clean is pretty compelling, I think. However, as constanze points, out, the medical recommendation is:
[snip]… to avoid the most prominent, allergy-causing foods like nuts in the first two or three years, to lower the risk of developing allergies. And let the kid play in the dirt, of course.
That is incredibly self-contradictory: we think the problem is that kids don’t get to develop a tolerance to environmental allergens, so let them eat dirt. BUT, don’t expose them to the very allergens that we’re most concerned about.
[/quote]
I think you misunderstood the important part of my sentence: avoid certain, allergy-causing foods in the first two or three years. Just as medical opinion is to avoid things like Sauerkraut and other cabbages for toddlers, because their stomach isn’t up to digesting these, but you can give Sauerkraut to a 10-year old. Resistance to common bacteria and the like is built up slowly, while the child develops. “Playing in the dirt” doesn’t wiping and disinfecting every surface in sight, and when the kids get older, they play naturally in the dirt and come into contact with things slowly, so they can adapt to it.
Likewise, if you give a four-year old nuts to eat, it may not cause an allergy to develop, but if you regularly fed a one-year old nuts, it might trigger an allergy to develop.
Let’s not forget that before 1990, people - adults - have developed allergies to stuff after years and years of exposure: famous are flour dust allergies in bakers, or latex allergies in nurses, doctors etc. Often, these people have had contact with the allergen for decades, and suddenly, their system can’t cope anymore. Obviously, there’s still a lot we don’t know about allergies; obviously there are several factors, obviously, genetics may play some part, but how much the genetic condition develops depends on behaviour after birth, obviously there are several different types of allergies, and different intensities in individuals.
Your point about multiple factors and difference in individuals is always an important one to make in medicine and biology. But apparently, the advice to keep the typical 5 or 10 allergens away from the kid during toddler years, esp. if you suspect the kid might have inherited allergy potential, and feeding a healthy*, balanced diet otherwise, and letting the kid play in the dirt, seems to work for many people, at least according to personal anecdotes. (I don’t know if any studies have been done on this). And this recommendation isn’t unhealthy or unsafe, so what’s the problem with trying it?
*healthy in this case means not only vitamins and fiber, but specifically natural foods, without artifical flavours, colours, preservatives etc., since these chemicals seem also to be related to allergies.
Besides, if the vast majority of allergic people - kids and adults - (real allergies, not the hypochondriacs) are allergic to the same recurring proteins, like nuts, which also occurs in some grasses, or tomatoes, or strawberries, then it seems reasonable to assume that something about the shapes of these specific proteins seems to be a problem for the immunesystem under certain circumstances.