Some liquid vitamin D supplement products on the market come with droppers that could allow parents and caregivers to accidentally give harmful amounts of the vitamin to an infant. These droppers can hold a greater amount of liquid vitamin D than an infant should receive.
"It is important that infants not get more than the recommended daily amount of vitamin D," says Linda M. Katz, M.D., M.P.H., interim chief medical officer in FDA's Center for Food Safety and Applied Nutrition. "Parents and caregivers should only use the dropper that comes with the vitamin D supplement purchased."
Vitamin D promotes calcium absorption in the gut and plays a key role in the development of strong bones. Vitamin D supplements are recommended for some infants—especially those that are breast-fed—because deficiency of this vitamin can lead to bone problems such as thinning, soft, and misshaped bones.
However, excessive vitamin D can cause nausea and vomiting, loss of appetite, excessive thirst, frequent urination, constipation, abdominal pain, muscle weakness, muscle and joint aches, confusion, and fatigue, as well as more serious consequences like kidney damage.