SignatureMD Minutes: Vitamin D
Vitamin D is a group of fat-soluble vitamins, the two major forms of which are vitamin D2 and vitamin D3. Vitamin D without a subscript refers to either D2 or D3 or both. Vitamin D3 is produced in the skin of vertebrates after exposure to ultraviolet B light from the sun or artificial sources, and occurs naturally in a small range of foods. Vitamin D was initially discovered in 1921 and was the fourth vitamin to be named and was found to be a cure for rickets. The mechanism for this effect on strengthening bones involved the ability of vitamin D to enhance absorption from the intestine.
Since its discovery, medical researchers have pinpointed vitamin D’s involvement with over 200 genetic pathways in the human body. Although the most common reason to supplement your diet with vitamin D is prevention of osteoporosis, it is now known that vitamin D3 supplements of 2000 international units daily has profound effects beyond prevention of osteoporosis including prevention of heart disease, prevention of cancer, improved immunity, and resistance to depression. D3 supplementation is especially important in northern latitudes during the winter months.
The risk of taking too much supplemental Vitamin D3 is very low. In fact, a person would need to consume large quantities of Vitamin D3, over a period of weeks, before reaching a toxic level. The only documented case of pharmacological toxicity from Vitamin D found in the literature was intoxication from an over-the-counter supplement called Prolongevity. The capsules consumed contained up to 430 times the amount of Vitamin D contained on the label (2,000 IU). The man had been taking between 156,000–2,604,000 IU of Vitamin D a day for two years. He recovered uneventfully after proper diagnosis, treatment with steroids, and sunscreen.
*Symptoms of Chronic Vitamin D toxicity: The early vitamin D toxicity symptoms include, gastrointestinal disorders like anorexia, diarrhea, constipation, nausea and vomiting. Bone pain, drowsiness, continuous headache, irregular heartbeat, loss of appetite, muscle and joint pain.