Does dairy in my diet lead to my baby's colic?

Absolute Maybe. In point of fact, there are numerous studies that demonstrate in some women and babies, that dairy does lead to colicky behavior. It may not bother all babies, but does effect some. A dairy elimination diet is the best method to find out.
No. Some people believe milk-drinking by a breastfeeding mom can cause baby colic. It is uncertain if this belief is true or not. Perhaps, in some mothers, some cow-milk proteins get into their breastmilk . . . And somehow cause cow-milk allergy symptoms or colic in their babies. So, it is fine for a mom to stop dairy intake for 2-3 weeks just to see if her baby becomes happier and less colicky.
Yes. The only method to know for sure involves completely removing dairy from your diet for about a week. This can be a difficult chore since, besides the obvious sources of dairy such as milk, yougurt and cheese, dairy is also a common additive in other foods. You will need to learn code words when reading nutrition labels to find these hidden sources. Some common terms include casein and whey.