Types

• There are two types of Vitamin D: D2 and D3. Vitamin D3, called cholecalciferol, naturally occurs in fish, egg yolks and beef liver, and is produced by our skin during direct contact with sunlight. Vitamin D2, called ergocalciferol, is a plant-derived vitamin that has been used in supplements and food fortifications. The equivalency of D2 to D3 is contested, but studies have shown that Vitamin D3 is more efficiently processed by the body.
  
  

Deficiency

• Vitamin D deficiency impairs bone mineralization, leading to bone weakness and increased risk of osteoporosis, so aging women require at least 700 IU of Vitamin D to fight bone loss. Vitamin D deficiencies in women may also influence energy levels, mood and immune functioning. Women who do not spend much time in the sun or eat many Vitamin D-rich foods are most susceptible to Vitamin D deficiency.
  
  

Benefits

• In addition to strengthening bones and fighting bone loss in aging women, adequate levels of Vitamin D help to maintain normal hormone levels, enhance fertility and strengthen the immune system. Cancer research at Dartmouth University indicates that Vitamin D helps make breast cancer treatment more effective by limiting cell death during radiation. Vitamin D treatment may help women with polycystic ovary syndrome regain and regulate their menstrual cycles.
  
  

Pregnancy

• Pregnant women with a Vitamin D deficiency are at high risk for pre-eclampsia, a condition that causes high blood pressure, kidney failure and seizures. Pregnant women require between 2,000 and 4,000 IU of Vitamin D daily. Vitamin D deficiency in pregnant women leads to Vitamin D deficiency in the fetus and may stunt development. Inadequate fetal Vitamin D levels have been linked to autism and poor skull development.
  
  

Hypersensitivity

• Vitamin D may be toxic if taken in extremely high doses. There are more reports of overdose on ergocalciferol, known as D2, than cholecalciferol, or D3. Complications from excess Vitamin D are uncommon, but some diseases cause hypersensitivity to Vitamin D. Hyperparathyroidism, granuloma, sarcoidosis and some cancers cause hypersensitivity because an abnormal amount of Vitamin D is produced by the body.