Vitamin D

General Description:

  • sunshine vitamin
  • fat-soluble vitamin
  • not only a vitamin, but also a hormone
  • comes in several forms, some of which are natural and some of which are synthetic
  • vitamin D2 (ergocalciferol) is synthetic and vitamin D3 (cholecalciferol) occurs naturally in some foods and is made by our skin when exposed to the sun’s UV rays


  • plays a key role in calcium and phosphorus metabolism
  • vitamin D and calcium have been linked to a reduced risk of colon cancer as calcium seems to tie up carcinogens in the digestive tract, preventing them from causing damage to the colon wall
  • necessary for healthy function of parathyroid and thyroid glands
  • essential to the formation of teeth and bones


  • 30 minutes/day in the summer sun produces a lot more vitamin D than the RDA of 10mcg. (1 mcg. is equal to 40 IU)
  • rickets is the final stage of vitamin D deficiency in children and it is called osteomalacia in adults
  • inadequate vitamin D prevents the body from absorbing enough calcium and without calcium osteoporosis is a major risk factor
  • body’s ability to make vitamin D declines as you age

Interactions and Toxicity:

  • vitamin D is the most toxic of all vitamins
  • damage from too much can be irreparable under certain, unfortunate circumstances
  • you cannot overdose on vitamin D via the sun, but you can using supplements
  • classic symptoms of overdose are: loss of appetite, nausea and vomiting, abdominal pain, excessive urination and thirst, and headaches
  • excessive vitamin D in the blood leads to excessive calcium in the blood (hypercalcemia), which can be a serious medical condition
  • if calcium is severely elevated in the blood, muscles may weaken and symptoms such as confusion, delirium, and coma can occur
  • in addition, in the most extreme cases shock and death may occur
  • to remove excess calcium from the blood, the kidneys may direct it into the urine for excretion leading to the possibility of developing kidney stones and if calcium level gets too high the kidneys may fail
  • calcium is found in 90% of all kidney stones in the USA
  • vitamin D overdose can cause permanent kidney damage or calcification of other organs, such as the lungs and stomach
  • children, and especially infants, are more sensitive to vitamin D supplementation
  • infants can develop a rare disorder called idiopathic hypercalcemia which slows the infants growth, produces an ”elfin” facial appearance, kidney malfunction, and severe mental retardation
  • research in animals indicates that a high intake of vitamin D can be hazardous to the arteries
  • barbiturates, certain anticonvulsants, cholesterol-lowering drugs, cortisone and certain laxatives increase the need for vitamin D


  • vitamin D is unique because our main source is not food, but rather the sun
  • sunlight activates a compound in the skin (7-dehydrocholesterol), which the liver and kidneys convert to the active form of vitamin D
  • fair skin is more cooperative with this process than dark skin, which lets in less of the sun’s D-making rays
  • window glass screens out UV light, which activates the D-forming process
  • egg yolks, milk, butter, sprouted seeds, mushrooms, sunflower seeds