The EclecticPhysician

The Eclectic Physician
Vitamin and Mineral Information

Vitamin D

The information on this page compiled by
Beth Burch N.D.
(click on the keywords)


Vitamin D is vital to maintain normal calcium levels in the blood. It increases calcium absorption from the intestines, increases calcium reabsorption in the kidneys and mobilizes calcium from the bones. It also stimulates normal mineralization of bones and teeth. Deficiency of vitamin D is known as rickets in children and osteomalacia in adults. Rickets is characterized by softening of the bones with subsequent deformity, poor sleep, and muscle tetany. Osteomalacia results in demineralization of the bones with deformity. Since vitamin D is manufactured in the skin by the action of ultraviolet light on 7- dehydrocholesterol, deficiency is more common in far northern and southern latitudes where exposure to sunlight is restricted in the winter. In the US, dairy products are supplemented with vitamin D, so deficiency is rare in those who consume plenty of milk. However, vegans, those with malabsorption diseases and alcoholics may be deficient. Vitamin D must be activated in two steps, one in the liver, the other in the kidney, so people with kidney or liver disease often have deficiency despite adequate intake or manufacture of inactive vitamin D.

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  • Ergocalciferol (Vitamin D-2)- the most common supplemental form
  • Cholecalciferol (Vitamin D-3)
  • Calcitriol (activated cholecalciferol)- prescription form for people with kidney disease

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Food Sources

  • The best natural food source of vitamin D is cod liver oil. Cold water fish like salmon, mackerel and herring are good sources. Supplemented dairy products supply plenty of vitamin D.

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  • Recommended Daily Allowance (RDA)
  • Infants- 300-400 IU
  • Children (ages 1-10)- 400 IU
  • Adults- 200-400 IU
  • Pregnancy- 400 IU
  • Lactation- 400 IU

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Optimal Supplementation

  • 400 IU daily

Treatment of Health Conditions

  • 400-800 IU daily

Conditions used for

  • Osteoporosis (with Calcium) (1, 2, 3)
  • Migraine headaches (with Calcium) (4, 5)
  • Vitamin D deficiency

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Side effects

  • Very high doses cause nausea, vomiting, weakness, headache, kidney stones, diarrhea and soft tissue calcifications

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  • Sarcoidosis, hyperparathyroidism, kidney stones, vitamin A toxicity, and possibly atherosclerosis

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Interactions with other nutrients

  • Increases calcium and phosphorus absorption
  • Vitamin D & vitamin K may have a synergistic effect in preventing bone loss (1)

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Interactions with medications and herbs

  • Ergocalciferol with cardiac glycoside medications may cause heart arrhythmias
  • Vitamin D and magnesium antacids may cause elevated magnesium levels
  • Corticosteroids counteract vitamin D
  • Cholestyramine, phenobarbital, phenytoin, colestipol and mineral oil all interfere with absorption or utilization of vitamin D

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1. Matsunaga S, The effect of vitamin K and D supplementation on ovariectomy-induced bone loss, Calcif Tissue Int 1999 Oct;65(4):285-9
2. Baeksgaard L et al, Calcium and vitamin D supplementation increases spinal BMD in healthy, postmenopausal women, Osteoporos Int 1998;8(3):255-60
3. O'Brien KO, Combined calcium and vitamin D supplementation reduces bone loss and fracture incidence in older men and women, Nutr Rev 1998;56(5 Pt 1):148-50
4. Thys-Jacob S, Vitamin D and calcium in menstrual migraine, Headache 1994;34:298-301
5. Thys-Jacob S, Alleviation of migraines with therapeutic vitamin D and calcium, Headache 1994;34:590-2

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* The information presented in this web site is intended to inform and educate. It is not intended replace a qualified medical practitioner to diagnose or treat medical conditions.

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