My mom pointed out a story to me from MORE Magazine about a woman who was horrified to find out her 1 year-old son had Rickets. Rickets is a softening of the bones potentially leading to fracture or deformity (from Wikipedia). Vitamin D is needed in the body to absorb and retain calcium. There are other serious complications that can arise in adults due to vitamin D deficiency.
Rickets was a disease of only the developing world where malnourishment was prevalent until the industrialized era in Britain. For the first time, breastfeeding mothers were not exposed to enough sunshine and children began to present deformities.
The mother in the magazine article thought that by breastfeeding her son, she was doing what she was supposed to - what was best for him. It's always a battle to get vitamin D into my daughter but we dose her daily regardless of whether we'll be in the sun or not. If you're a breastfeeding mom and you didn't know about the importance of vitamin D or Rickets, please talk to your doctor about it.