Could I be Lactose intolerant and not even know it?

hi angela, thank you for your comprehensive response. i'm so excited to be accessing your knowledge! last question: can one fight a sensitivity? i drink milk several times a week and i often get asked, "you drink milk? aren't you lactose intolerant?" i guess asians are more prone to lactose intolerance than other races. however, i have never felt lactose intolerant or frankly, i simply dismiss that it applies to me. if someone has lactose intolerance or any food allergy, can they trick their body out of it?

Well actually yes. You could definitely be lactose intolerant and not know it. There is a range of lactose intolerance from extreme (as in you take a couple of sips of milk and you get immediate cramping etc) to mild (you can drink a cup of milk and be OK as long as you sip and not chug). It is well known that one can essentially train themselves to tolerate small amounts of dairy even if they are lactose intolerant (i.e. officially cannot digest/break down lactose into glucose and galactose).

There are ways to be tested for lactose intolerance (breath tests), but most doctors don't bother to administer these tests. One way to find out is to eliminate dairy from your diet and see if you get an exaggerated response after you add it back in. But why would you do that to yourself? If the dairy you are having now is not bothering you there is no reason why you wouldn't just keep it up. 

Lactose intolerance is not like an allergy or sensitivity in the sense that "hidden" allergies or sensitivities could be sensitizing your immune system and causing chronic low-grade inflammation. Lactose intolerance is a simple inability to break down the lactose sugar into its constituents, which causes physical effects in your intestine and potentially affects your microbiota. But there is no evidence that a "hidden" lactose intolerance could be having negative effects other than the obvious ones. 

Other food sensitivities are a different thing. These, like gluten sensitivity for example, could definitely be having some additional effects that go beyond cramping, bloating, and diarrhea and could be leading to chronic low-grade inflammation.