Doctors generally recommend taking vitamin D from 2 weeks to 2 years old. Because breast milk and food do not contain vitamin D, it is easy to lack vitamin D if you don't get enough sunlight.
The daily requirement of vitamin D is 400 international units. Don't overdo it. Eating too much is easy to be poisoned. Some doctors say that if you can get more than 1 hour of sunshine every day, you don't need to take vitamin D. My second treasure played outdoors for several hours and took vitamin D intermittently. Eat when you think of it, and don't eat when you forget it.
In short, vitamin D can be supplemented appropriately, and probiotics and calcium can be supplemented appropriately when necessary, so it is not necessary to supplement them all the time. Children's nutrition still needs to be supplemented by daily food, and no supplement can replace food. Believe in the baby's strong body adjustment ability.