It is a little more involved than any possible issues with lactose. At it's most basic the paleo argument against diary is that we didn't evolve drinking other animals milk, and we would of only consumed our mothers milk during early childhood, during a period of rapid growth.

The point of rapid growth is important in that there is an argument that the anabolic affect of milk, possibly due to the insulin like growth factor 1 (IGF-1) within it, may not be optimum for adults to consume - who aren't experiencing rapid growth - as obviously adults are fully grown. Of course it is the anabolic properties of milk that has made it popular with body builders and the like.

Then there is the issue of casein, a milk protein, that some people don't seem to deal with too well. It turns out that most cows in western herds have a mutated gene, and thus produce a casein called A1 - it appears that most people who have an issue with casein only have an issue the A1 variant. The other casein type is A2, and cows who do not have the previously mentioned mutated gene produce it in their milk, along with sheep and goats who don't have the mutated gene in their species. This is often why some people who don't do well on cows milk have no issue with goat or sheep milk.

And of course, back to your first point, some people are indeed lactose intolerant - meaning that they have issues breaking down the lactose in milk. I'm not that well read on lactose intolerance but it is my understanding that it could be due to inappropriate gut bacteria, and can be solved buy eating fermented dairy (yoghurt) that contains the bacteria to break down lactose, so said bacteria can begin to populate the gut.

I guess a discussion on dairy wouldn't be complete without mention of the African tribe, the Maasai. There diet was primarily made up of cows milk & blood and meat, and the tribe showed no signs of western disease. For what it's worth their cows produced A2 milk.

So should you consume dairy? It depends. How does it effect you? Not sure? Eliminate it for 30 - 60 days and then re-introduce it.

Personally if I was going to consume diary I would opt for it in it's fermented forms. If I was going to consume milk straight up it would be A2 raw, whether that be from cow, goat or sheep.

Lactose free milk is a Neolithic frankenfood. If you want a more natural lactose free dairy product eat cheese. As suggested, also consider eating fermented milk products such as yogurt, buttermilk and sour cream. The bacteria convert a lot of the lactose into lactic acid, reducing the glycemic index substantially. Unsweetened yogurt has an index of 15-20, vs the equivalent milk at 40-50. It's not as low as fat and protein (0 index), but it's an improvement.

It depends why you are cutting the lactose. I think strict paleo for most people means dairy free but lactose free milk is good if you are limiting carbs for weight loss.

Might want to check out this talk on milk from AHS:

http://vimeo.com/27671369

hello,i am on a diet,but love milk i have been on semi skimmed since starting my diet,and heathy eating,could i ask if lactose milk will be better again than semi skimmed.thank you carol.