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, as is seen with the condition known as rickets.t 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..