What is the difference between digestion of milk and artificially taken calcium supplement in body?

Vitamin D. Vitamin d which is often fortified in milk can help with the absorption of calcium by the body. Please note, however, that dairy is not the only food source of calcium: dark green leafy vegetables and soy foods are also excellent sources.
Depends on you. Many people are sensitive or even allergic to milk. Lactose, the milk sugar can cause gas, bloating and/or diarrhea. Some can get severe constipation. Most milk contains a hormone given to cows to produce more milk. The fda says it is safe but there are no long term safety studies. Calcium supplements come in different types and none work in everyone. Be sure it is tested for lead.