allergies and lactose intolerance

I’ve heard so many people say that they used to drink milk all the time, and somewhere in their teen years, they became lactose intolerant. I used to be able to eat bananas all the time, and then they started making my teeth and gums sting, and my brother used to eat tomatoes, and when he was 19 or 20, they started to make his lips sting. I used to use bandaids all the time, and just a few months ago (I’m already 21,) I suddenly became allergic to adhesive. It seems to me that allergies(and lactose intolerance) don’t really start at birth, but sometimes occur later in life. So what is the medical science behind it all? I’m really curious, so please do, pray tell. :slight_smile:

Both. Allergies can start very early in life - that’s why some foods are recommended to not feed small children, as they can “jump-start” an allergy when the babies are still developing everything.

But allergies can also develop later in life - a baker who after 40 years of work suddenly gets allergic to flour dust is the classic example.

Medical science has some points about allergies, but not the whole model.

We know that allergies are a mis-direction of the immune system, where it reacts to normal, harmless, everyday substances as if they were dangerous, causing an immune reaction, from hayfever with swollen nose and runny eyes, up to anaphylactic shock, where your throat swells up and die.

There are studies that suggest that our too-clean homes are a factor in this - because children who grow up in the countryside and have contact with shit and animals and stuff (that would cause allergies in adults) have less allergies than city-kids. So eating a mouthful of earth might help you against allergies (exaggerated).

There is also the observation after the fall of the Wall that ruled out air pollution particles and put the blame on artifical additives (colour, taste, preservation etc.) in food: in East Germany, the amount of coal dust and similar pollution in the air was even worse than in West Germany (because there was no independent enviroment movement to pressure politics to pass strict laws); but the food had almost no chemical additives besides absolutly necessary preservatives (because additives cost money, and in a planned society, there was no need for competition of brand X against brand Y - people were glad to get any jam or soda at all, no matter the colour or taste) - and there were significantly less allergies in people in the DDR than in the BRD.

Genetics also play a role - two mildly allergic parents often have serious allergic children.

There’s also cross-allergies: if you start out allergic against one type of food, like hazelnuts, often you also get allergic to similar things from the same plant family, like certain grass blooming.

Because we don’t know all causes, we don’t know the best treatment, either. Some people have success going all whole food or organic or vegetarian. Others try hypersensitivity - they are exposed to small doses of allergen every year until the body realizes that blooming birches are harmless and not a danger. Some just take meds against the swelling during the blooming season and bear it (or move to the mountains/ seaside where no pollen is in the air).

Lactose intolerance is something completly different however. It means your body stops producing the enzyme lactase that helps breaking down the milk sugar lactose. Since this is a genetic mutation of Western Europeans that allows the production of the enzyme after weaning at all, to loose it later in life is not much of a surprise. Today, many lactose-free cheeses and other products are available, and even L- milk (or Soy milk). Or you buy lactase tablets that contain the enzyme to take just before the milk.

To add: often it’s not an allergy, but a reaction to a hormone (like Ananas, papaya) or protein (like in milk) heating will denature it and allow eating without reaction.

That’s also a point for milk: many people are lactose-intolerant, that is, they react to milk sugar. This is contained in milk, but not in older ripened cheese (because the sugar has been converted by the bacteria) or in cream (which is fat).

Additionally, milk sugar is often an ingredient in sweets (chocolate is made with powdered milk parts), but because it’s been processed, often doesn’t cause a trouble.

Other people have problems with milk protein causing gas, and they need to avoid other milk products that contain protein, or heat the milk.

One difference between allergy and intolerance is the threshold: does the smallest amount cause an reaction (Cecil wrote about peanut butter and gave a case of a kid being kissed after somebody had eaten peanut butter)? Or is a small amount fine, only a bigger amount a problem?

As for the band aids - did you change the brand? Different brands use different adhesives, and some are better for the skin than others.

Just to make sure I understand isn’t an allergy just an error by the body. In other words the immune system is thinking that a benign protein, let’s say in a peanut is really some kind of germ and it makes antibodies or reaction to it?

Yes, the immune system thinks that a harmless substance - particles from dust mites, peanuts, pollen - is a danger. It’s not as specific as mistaking it for a germ, it’s more of a general reaction, and it’s not limited to proteins.

That’s why the “contact with dirt” theory sounds plausible, the immune system during the learning years = when the child is young, has contact with lots of real germs and can learn what things are a real danger and which are harmless, while a child in a city apt. where everything is wiped with lysol doesn’t have contact with enough substances. A theory is that the immune system is programmed to always attack something because sterile homes are a new and unnatural development compared to the natural enviorment where there are always real germs to fight against.

And again to be clear, that’s the way an allergy works, but not the way lactose intolerance works. With lactose intolerance, the body doesn’t think the substance is an invader that needs to be fought off; it just doesn’t know what it’s supposed to do with it (due to lacking the specific enzyme that’s used to deal with that substance). In the case of lactose intolerance, since it doesn’t know what to do with the lactose, it just passes it along through the digestive system, until it gets to intestinal bacteria who do know how to use lactose, and make stinky gas in the process.

Also note that lactose intolerance is actually the normal state for adult humans: Most populations produce lactase (the enzyme that breaks down lactose) as children, and then stop producing it after they’re weaned. There just happen to be a few populations (including Europeans) where adults retain that enzyme.

The same is also true of most other mammals, so don’t give milk to pets.

So basically, the allergen (flour dust, peanut oil, etc) enters your body. It isn’t supposed to be there, so your immune system destroys it. Then some of your white blood cells make an antibody that recognizes the allergen. This antibody binds to mast cells (another kind of white blood cell). When the mast-cell-bound antibody encounters the antigen (second exposure), the mast cells will lyse and release a bunch of inflammatory things, which cause the allergic reaction.

Well, yes and no. The antigen theory is the old definition of allergy, and therefore required specific proteins. If your antigen count wasn’t raised, or if the substance didn’t contain proteins, you didn’t have an allergy.

In the past years, however, doctors have encountered people with allergies to non-protein substances or even no substance at all, like cold, heat and sunlight (no, not vampires) - people get allergic reactions, that is, breaking out in hives with raised histamine count, despite no raised antigen count. So medicine is debating on how to classify, explain or treat this properly (besides giving anti-histamine to make the swelling go away and telling “avoid what causes the reaction”.

We might end up with different mechanisms for different people, as seems the trend for other wide-spread diseases, too. People seem to be much more different biochemically than a normal textbook makes us believe.

It does start to become an issue of how words become defined. And admittedly it can get a little squishy.

There are all kinds of reactions.

Reactions caused by the body reacting to a foreign substance by producing a certain kind of antibody (or immunoglobulin), type E. This gets abbreviated as IgE. IgE triggers other cells to then release histamine which causes the traditional allergy response of hives, itchy eyes, airway reactions, and so on. This is a very rapid sort of reaction and is clearly called by all “an allergy”. It takes repeated exposure to develop. So correct, they are not there at birth. This type of food allergy can develop early and then go away by a few years of life (like milk protein allergy), or it can be a more likely to persist type (like peanut allergy). It can develop much later as well. For years it was thought that avoiding exposure til a child was older might help avoid the allergies developing but it turns out that such is not the case. These reactions are generally to proteins. Milk protein allergy can cause hives, can cause diarrhea, even bloody diarrhea, but is not the cause of gassiness a few hours after drinking milk.

Histamine reactions triggered without IgE being involved. Hives triggered by cold, for example. Or a not too uncommon food reaction to MSG. Not considered “allergic” by most, even though it has the same endpoint, because the immune reaction piece is missing.

Other immune reactions to food mediated by different antibodies. Celiac disease falls into this group, mediated by IgA. No histamine involved but an immune reaction of IgA to gluten attacking parts of the body. Allergy? Most don’t call it such. But eczema triggered by foods (which it occasionally is), not IgE or IgA mediated, presumably IgG but for which testing is notoriously unreliable, is fairly commonly called an “allergic” reaction. Then again a host of other antibody reactions against our own body that are not IgE mediated get called “autoimmune” rather than “allergic”.

And then there are the host of food intolerances, like lactose intolerance, or a food triggering a migraine, or a reaction to the enzyme in papayas, that are not immune or histamine mediated. Lactose intolerance of course does cause gas and shows up as most mammals age as drinking milk outside of early childhood is recent development evolutionarily speaking (as Chronos explains).

So yes, in general, an allergy is as Quetzl describes it, with the small addition of both mast cells (which are fixed in place) and eosinophils (which move about the bloodstream to different locations).

[nitpick] The lactase-into-adulthood mutation is also seen in several African groups (the Masai are probably best known) and thus it is not an exclusively European trait. It has apparently arisen independently more than once. [/nitpick]

Ah! I didn’t know that because so far when talking about milk-drinking adults, the reference is always to Europeans.

But of course the Massai are renowned for the status that cows have in their culture, and that they drink milk (and blood) from them. I assumed, however, that they would let the milk curdle or similar treat it, as the Mongols presumably did.

Oooh, that clears up the lactose intolerant question. :slight_smile: But as for allergies, I was wondering why the body would react to something all of the sudden that’s been in it for several years. I saw someone say, correct me if I’m wrong, that repeated exposure to the foreign substance causes the allergy to occur. Why does it take so long for the body to … um… “notice” it?

As for the bandaids, it was because I went to get blood drawn, and they put a large tape to hold the gauze in place. After that, I had a bad rash on that area, and on the soles of my feet. After that I couldn’t even use ordinary Band-Aid brand bandages.

We don’t really know.

Ah. Ok. Thank you for answering!

I am against lactose intolerance. People without toes are people too!

Wow, that was so awful, you made my day. XD

The bandage issue might be due to latex, not the adhesive. I can no longer use adhesive bandages. I am not sure if it is the adhesive itself, or if it is latex. I have very sensitive skin and cannot even tolerate the elastic on underwear. I use the spray-on “liquid” bandages and Coban LF (latex free) self adhesive wrap over gauze pads when I am trying to cover a cut or scrape.

Oooh! That actually makes perfect sense. That would explain why I had a rash after biology lab dissection…I think I’m starting to get sensitive skin too. I suddenly started getting allergic to a whole bunch of things.
Hmm… Coban LF…I was still looking for a good bandaid substitutes. Thanks! :slight_smile: