Yes. In fact, both milk and protein are rich in protein, and amino acids are only the building blocks of protein. In the absence of high temperature, high pressure or acid, there will be no reaction between protein and protein. As for lactose, it gets along well with proteins in milk and other proteins as well.
In short, there are many sources of protein supplements. They can be substituted for each other because the nutritional content and taste are similar. Due to people’s instinct to eat more types of food, they are generally not cooked together, but This habit does not mean it is taboo.
Another theory is that eating eggs and milk together will increase the burden on the gastrointestinal tract. Milk contains fat, and egg yolks are rich in cholesterol. Excessive intake will burden the body to varying degrees. But the main reason for gastrointestinal burden is eating too much.
The last theory is that eating milk and eggs together can cause diarrhea. In fact, it is more likely that it is just diarrhea caused by milk. A large proportion of Asians are lactose intolerant. Just drinking milk can cause diarrhea. In this case, you should choose low-lactose milk, or not drink milk at all. But this has nothing to do with eggs, and it has nothing to do with "eating milk + eggs together".
Extended information
Milk and eggs are believed to be a breakfast that many people often eat to lose weight. In fact, the combination of this breakfast is not scientific. In the early morning, the human body needs food rich in carbohydrates. Breakfast replenishes energy. Both milk and eggs are rich in high protein, but they can only supply the needs of the body structure, but cannot supply its energy. People will be hungry soon after eating milk and eggs for breakfast, which will damage the gastrointestinal tract.
The staple food must not be missing when eating breakfast. After drinking milk and eating eggs, it must be paired with staple food such as gruel, bread, and steamed buns, so that people can eat more nutritiously and resist hunger. The time is also longer.
Reference: Ifeng.com - Can eggs and milk be eaten together? The nutritional value of eggs