A vitamin D supplement of 400 IU should be given to all babies who:
are breastfed exclusively or partially
drink less than 1000 ml (35 oz) of commercial baby formula daily
Normally, exposure to sunlight allows the skin to produce vitamin D in sufficient quantities to meet needs. However, since babies should not be exposed to direct sunlight during the first year of life, mothers should help babies meet their vitamin D needs through diet.
Few food items contain Vitamin D naturally, aside from fish and eggs.
In Canada, milk and other foods such as margarine and certain juices are fortified with vitamin D. Commercial baby formulas are also fortified with vitamin D; they are indeed the major source of vitamin D for infants in their first year of life. It remains difficult for a baby to fully meet its vitamin D requirements through diet alone. As a result, Health Canada recommends giving babies a daily supplement of 400 IU of vitamin D until their diet can provide the amount needed. As an exception, babies who consume more than 1000 ml of commercial baby formula each day do not need this supplement.
Since vitamin D accumulates in the blood, it is important to respect the dosage indicated by the manufacturer of the vitamin D supplement (1 ml or 1 drop per day, according to the product). This way, there is no adverse health risk for the baby to consume commercial baby formula in combination with the recommended daily supplement of vitamin D.