I need a refresher, because I thought cheese I was perfectly safe until just now. Also, please give me some advice on butters and yogurts, like greek yogurts. I have found that lactose and casein explode my acne production so I want to stay away from them as much as I can.
If you're looking to avoid both casein (the primary milk protein in addition to whey) and lactose (milk sugar) you can simply focus on cream only (milk fat) products.
This would include sour cream, cream cheese, heavy cream, butter, ghee, etc.
Yogurt and cheese have less lactose because the bacterial cultures use it up as food while it ages/ferments. The bacteria do not consume the milk proteins, however, so it remains intact in the final product.
As other noted, there is a difference between the type of casein found in different types/species of ruminants. Alpha-lactalbumin and beta-lactoglobulin are the two main types found in cows milk and it is thought that the beta-lactoglobulin form is primarily to blame for milk allergies.
Going even further, the problem is thought to be the result in a mutation in cows (this mutation has not been detected in goats or sheep) that causes some to produce a type of beta-lactoglobulin that is particularly problematic (a proline molecule is replaced by a histidine molecule).
This difference is sometimes designated as A1 vs A2 (with A1 being the "bad" kind). As you can probably guess, most U.S. dairy cows (primarily Holsteins) are the A1 kind. This is because they produce prodigious quantities of milk. In countries where milk quality is the prime concern, you will still find A2 breeds such as Jerseys.
"Beware, Bad Cow"
"Ignore the horns, this is a good cow!"
I'm fairly lactose intolerant, and I use ghee for cooking very frequently. The clarifying process also removes casein. I'm sure there are trace amounts of both in ghee, but you may find you handle it rather well.
Agree with Wozza - goat's and sheep's milk are much better from a casein perspective.
However, I don't agree about having to cut dairy altogether. My n=1 experiment showed that as long as you're consuming the dairy as homemade fermented yogurt, the acne stayed away. The minute it was consumed without friendly bacteria, the acne returned. If you ferment the yogurt for long enough, the bacteria consume all of the lactose and multiply to great numbers, increasing the potency of the yogurt exponentially.
Diets like GAPS propose that these types of dairy shouldn't be a problem for most people after allowing your gut to heal for some period of time and Chris Kresser even points to a study that shows fermented dairy w/ L. Acidophilus cleared up the skin even further:
In the past year experimenting with Lacto-Paleo (including 30 days of dairy elimination), this is what I found for the hubby and I:
We can consume any type of raw dairy - milk, butter, cheese, cream, sour cream, cream cheese, ice cream, heavy cream, yogurt with NO symptoms. We feel great in fact.
I've only experimented up to 3 raw dairy servings/day - haven't tried more then that because then I'd have to reduce the nutrition of other foods I like such as meat, veggies, starches, etc.
We can consume any amount of pasteurized grass-fed dairy of cream, butter, and ghee with NO symptoms. These are minimal to no lactose/casein foods.
Now milk, cheese, and yogurt if we have more then 2 servings of milk, cheese, or yogurt per day as pasteurized then acne flairs up.
I now understand why WAPF are obsessed with raw dairy.
The Mayo Clinic states the following dairy contain casein: All milk, butter (which means cream, heavy or half and half, yogurt, kefir, cheese, etc. Only ghee (clarified butter) has had the casein protein removed. The Mayo clinic adds that mothers who breast feed (nurse) their babies who drink milk may pass on the allergy or sensitivity to their baby and even cause the baby to refuse to nurse or become ill from the bleed off of cow's milk from the mother's diet. The problem here, in the answers, it's largely anecdotal and opinion, in fact, I looked up the USDA, Dairy science at the UW (University of Wisconsin) and typed in casein cream connection. Nothing came up, so, the Mayo cllinic will have to do. The Mayo Clinic, once the Mayo Foundation used raw milk in the early part of the last century to cure ills, specifically, Dr. Crewe, a Mayo Foundation founder.
Lactose is a sugar, so read the label. If there's no sugar, there's no lactose. Many cheeses (like cheddar) are "naturally" lactose free because it's removed by the standard method to make that cheese. Some cheese-making procedures, especially for softer cheeses, do not remove the lactose, but it's still pretty low because lactose is turned into lactic acid to make any cheese.