Are some safer than others? Yogurt, butter, cheese, or curds and whey?
Don’t know if it’s the same as the allergy-du-jour, but innately lactose intolerant Chinese people can drink and eat yoghurt products.
Aged cheeses contain very little lactose, so most lactose-intolerant people could eat those. Cheddar and parmesan are common examples of aged cheeses.
Lactose intolerance isn’t like peanut allergies, which can be deadly if the person ingests even a trace of peanuts. Most lactose-intolerant people have some tolerance for lactose, but not as much as a lactose-tolerant person. It’s not necessarily a question of “what foods can’t you eat”, but “how much of whatever food can you eat”. Dietary control of lactose intolerance depends on people learning through trial and error how much lactose they can handle..
Allergy-du-jour? Are you trying to be funny? Okay, bub, bring me some ice cream, milk, yogurt, and cheese and stick your face under my ass for the next few hours. That’ll be funny.
No wonder I didn’t have any luck trying to sweeten my coffee with parmesan cheese! 
Lactose intolerance has been around for centuries, and isn’t really an “allergy”. Basicly, as one gets older, and drinks less milk, the various bacteria and enzymes that brak down lactose go away. Thus, when you consume lactose, it does the following: gas, bloating, diarrhea and sometimes other problems.
Products containing “live culture” are often safe, as are aged cheeses.
Based on what I’ve picked up on “Good Eats” (aka: I’m not a doctor and this could easily be wrong), people with lactose intolerance just can’t digest the lactose sugars in dairy products. This is due to intorant people lacking (or producing a reduced amount) of the enzyme that breaks up the lactose into more easily digested sugars. It gets through their digestive tract more or less intact to where gut bacteria latch onto it, break it up, and produce gas.
So the “safest” dairy products would be ones with a low amount of lactose. IIRC, live culture yogurt may be an exception, since the bacteria in it would help out a lactose intolerant person’s digestion. There are also over-the-counter supplements to give you a boost to the lactose-breaking enzyme.
There is such a thing as a true milk allergy, which is different from lactose intolerance and rarer. Depending on which component of milk a milk-allergic person is sensitive to (casein or whey), they might have to avoid some or all dairy products that a lactose-intolerant person could eat.
Well, it would be quite amusing for everyone apart from me. Same as if I ate a curry and did the same thing to you… 
Note the words in my post/ I used the phrase “allergy-du-jour” advisedly: not to insult lactose intolerants, but because everyone I know - and I mean everyone - who goes to a quack allergenist comes back and tells me “OMG guess what, I’m allergic to lactose!!11!!!One!” (and wheat too. Always wheat).
I’m prepared to be corrected, but AFAIK, lactose is a sugar. You can’t be allergic to a sugar, you can only be allergic to a protein. You might have an intolerance to milk products, but you don’t have an allergy.
(On preview, I see that you might have an allergy, but it’s unlikely.)
People don’t have allergies to lactose. Those of us who are tolerant to lactose have an enzyme, called lactase, in our intestines that breaks down lactose. Almost everyone is born capable of digesting lactose, but lactose-intolerant people (and animals) lose that ability sometime after they are weaned.
The fact that lactose intolerance isn’t a true allergy doesn’t mean that lactose intolerance is not a real condition. Something like 70% of all people in the world are lactose intolerant. It’s much less common in people of northern European ancestry, more common in people of African, Asian, Native American, or Aboriginal Australian ancestry. It’s not something made up by new-agey “allergists”. Of course, this doesn’t mean it isn’t over-diagnosed by said new-agey “allergists”. Wikipedia entry on lactose intolerance
True milk allergies, to casein and whey, do exist, and are much rarer than lactose intolerance.
Yeah. I don’t think of myself as “Lactose Intolerant” - I think of you normal people as never having been properly weaned. 
Self esteem is everything.
Or maybe Milk and Wheat are on the same list as peanuts, tree nuts, fish, shellfish, soy, and eggs and together cause 30,000 emergency room visits and 150 deaths a year in the United States. There is a reason Milk is on the “big 8” allergen list. Many people are legitimately allergic to common foods.
If you are allergic to milk, you avoid it like the plague. If you are lactose intolerant, eat aged, fermented dairy products and take your chances that you will be noticing your bathroom needs regrouted. Probiotics can help, but aren’t magic.
It’s been around longer than that. “Lactose intolerance” for adults is the normal condition in most mammals, including humans. It’s lactose tolerance that is the newbie here-- having become prevalent in populations which raised livestock for their milk. You wouldn’t have to go back more than, say, 10k years before you’d find most of our species to be lactose intolerant.
acsenray. your post is out of line for GQ. Please do not repeat this.
You have been warned.
-xash
General Questions Moderator
As a child, I was advised to eat as much yogurt and cheese as I could handle to make up for the calcium I wasn’t getting through milk. As an adult I can’t handle a large glass of milk well, but most processed dairy products pose no problem if eaten in normal amounts. My fridge brims with cheese and yogurt is my daily breakfast (you’ll notice this in a lot of lactose-intolerent countries- milk may be regarded as children’s food, but yogurt and cheese- often yogurt cheese- is heavily used).
Milk allergies are rare in adults, but can be deadly to infants (80% of which grow out of it by childhood). Almost killed me, for sure. I think the main danger is malnutrition from not being able to digest the milk, not a dramatic reaction (though that can happen). In any case, it’s rare to begin with and very very rare to see in an adult.
close but non-proteins can also be allergenic. For instance nickel or limonene
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11966698&dopt=Abstract
jjimm isn’t saying they aren’t, as far as I can see. He does have a point; allergy diagnosis is, in my experience, frequently haphazard and quackish. The fact that milk is a common allergy is indeed part of the reason for this; it’s very easy for an unscrupulous doctor to simply pick a couple of likely allergies and produce an exciting-sounding diagnosis without too much fear of being dangerously (or even detectably) wrong. Given that there is pretty much no reliable allergy diagnosis technique short of elimination diets (even scratch testing doesn’t work particularly well), pretty much all tests purporting to give you a same-day answer as to whether you’re allergic to something are likely to be a load of rubbish.
As a precise example of what jjimm is talking about, when I was 6 I was experiencing horrendous ear infections, and nearly burst an eardrum. Just before having grommets fitted, I was taken to an “applied kinesiologist”. This so-called diagnostic technique consists of getting the patient to hold a vial of a suspected allergen in one hand, and hold out their other arm parallel to the ground. The “doctor” then pushes down on the outstretched arm. Should the patient be allergic to the substance, his “energy” will be “disrupted”, and he will be unable to resist the “doctor’s” pressure. It gets better, however; being 6 at the time, I could hardly be expected to resist a fully-grown adult; not even an accomplished idiot. So I sat on my mother’s lap, I held the vial, and she held out her arm. The “doctor” performed his test, listened to a description of my symptoms (which were, it turns out, highly consistent with a dairy allergy), went into a back room for a bit, and came out and diagnosed me with the two most common childhood allergies, dairy and wheat. He was half right as it turned out, and for this remarkable demonstration of modern-day snake oil pocketed a tidy fee.
It’s this that jjimm is criticising: allergy diagnosis is heavily preyed upon by quacks, precisely because allergies are so common and so difficult to diagnose in a scientific manner. Just perform some complex magic, tell the person they’ve got an intolerance (which you already know with 80% certainty anyway, if the stat above is to be believed), and send them on their way, slightly poorer. It doesn’t diminish the fact that people do have these allergies in any way to acknowledge this.
It’s worse than that. These days many people are self-diagnosing to give themselves allergies to explain just about any symptom or set of symptoms whatsoever. It’s certainly true that a host of alternative practitioners prey on these people but many doctors seem to be just as clueless. It doesn’t help that the major tests for allergy have large numbers of false readings.
To echo what others have said. Infant milk allergies are common, although still a tiny minority. They manifest when the child is first given a milk formula. (In rare instances allergens can leak through the mother’s breast milk and cause symptoms. This is almost always the sign of a true and long-lasting serious allergy.) About 25% of these babies will also prove to be allergic to the soy formula that normally is the first replacement for the milk-based formula.
Most of these children will grow out of the allergy. The usual age range is from 2 to 3, but the variance can be great. Most estimates place the number of allergic adults at no more than 1% of the population.
True allergy is a reaction of the IgE set of antibodies. Other sets of antibodies may also cause protein reactions, and these are also sometimes called allergies, sometimes hypersensitivities or even intolerances. This is bound to cause all sorts of confusion, and certainly does.
Lactose intolerance (LI) is entirely different. Primary LI is the result of aging, and occurs in every mammal whose species produces lactose in its milk. The enzyme lactase reduces or disappears at about the time of weaning. This is the natural state of all mammals, humans included. The mutation which doesn’t send out the signal to stop lactase production occurs on a single gene on chromosome 2. It’s not uncommon so presumably there have always been lactose tolerant humans, but selection pressures couldn’t spread the mutation until dairying became common enough that being able to get the nutrients of milk became advantageous. This is probably no more than 5000 years ago, although herding did begin earlier. It’s the latest and most widespread mutation in human history, and one of the most culturally important. The association with white skin is no coincidence, since the need to process calcium in climates where the skin is not exposed enough to the sun to make the vitamin D that helps process calcium can be satisfied by getting calcium through milk. (Some evidence also indicates that making lactase helps digest calcium.)
Few children are naturally LI - for most of human history they would have died if so - but any disease or damage to the intestines can - temporarily or even permanently - disrupt the body’s lactase-making machinery. This is known as Secondary LI. Even the misnamed “stomach flu” can do this. About 1% of babies are LI at any given time, but they go back to making lactase as their intestines heal, usually in a few weeks.
What percent of adults are LI depends entirely on how you define it. If you go by whether they have the standard gene, then it’s true that about 70% of the world’s adults are LI. If you go by whether they show symptoms from a small amount of milk or dairy, the numbers are much smaller. This explains why dairy products are rapidly spreading in popularity in Asia, despite the genetic bias against them.
Much more information on anything you could want to know about LI can be found at Steve Carper’s Lactose Intolerance Clearinghouse, including lactose percentages in various animals’ milk, lactose in dairy products, the differences between LI and allergy, and pages of other stuff.
And you’re the one who used the word allergy in “allergy-du-jour.” I’ve never claimed that lactose intolerance was an allergy, only that it wasn’t a joke. Lactose intolerance is caused by lactase deficiency and its affects are real and very noticeable, regardless of how you label it.