Vitamin D

Cholecalciferol (Vitamin D3)


  • regulates absorption and transportation of calcium and phosphorus from the intestinal tract
  • maintains level of calcium in blood
  • takes calcium from bones when diet is insufficient in calcium



  • interferes with utilization of calcium and phosphorus in bone and teeth formation
  • irritability
  • weakness
  • hypertension (Forman JP 2007, Lee JH 2008)
  • cancer (Feldman 2014)
  • insulin resistance (Sung 2012)
  • Alzheimer's disease and dementia (Shen & Ji 2015)
    • Moderate deficiency of Vitamin D increased risk of dementia 53%.
    • Severe deficiency of Vitamin D increased risk of dementia 125%.


  • irreversible bone deformities in infants
  • rickets in young children
    • childhood deficiency disease marked especially by soft deformed bones
  • osteomalacia, osteoporosis, and hypocalcemia in adults


  • soluble in fats and organic solvents
  • relatively stable under refrigeration
  • stored in liver
  • precursor: UV-activated 7-dehydro-cholesterol

Good Sources


  • butter
  • egg yolks
  • oily fish
    • salmon, tuna fish, herring, sardines, mackerel, bluefish, catfish
  • oysters
  • liver
  • mushrooms exposed to sunlight (Stamets P 2004)
  • exposure to sunlight
    • formed in the skin
Food Quantity mcg IUs
Cheese, cheddar 1 oz 0.075 3
Egg 1 large 0.675 27
Milk, non-fat 1 cup 2.5 100
Red Salmon (canned) 1/2 cup 23.5 940
Cat Fish (cooked) 3 oz 14.25 570
Cod Liver Oil 1 T 34 1360
Multivitamins (most brands) 1 tablet 10 400


  • cod liver oil and fish oils
  • yeast
  • foods irradiated with ultraviolet light
  • fortified milk
  • Vitamin D2, or ergocalciferol is 25 percent less effective than Vitamin D3, or Cholecalciferol

Sun Exposure

  • In summer, as little as five minutes of sun a day on unprotected hands and face can replete the body's supply
    • Excess can be stored for later use
  • During the remainder of the year, most people need a dietary intake
    • People in the northern two-thirds of the USA make little or no vitamin D in winter
  • Freshly picked, indoor- grown shiitake mushrooms placed outdoors in the sun for 6 hours increase vitamin D (Stamets 2004)
    • with gills facing up
      • level of vitamin D in rose from 110 IU (international units) to 46,000 IU per 100 grams when the
    • with gills facing down
      • level rose from 110 IU to 10,900 IU.


  • Randomized trials using the currently recommended intakes of 400 I.U. vitamin D a day have shown no appreciable reduction in fracture risk. In contrast, trials using 700 to 800 I.U. found less fracture incidence, with and without supplemental calcium. This change may result from both improved bone health and reduction in falls due to greater muscle strength (American Journal of Clinical Nutrition 2007).
  • A Swiss study of women in their 80s found greater leg strength and half as many falls among those who took 800 I.U. of vitamin D a day for three months along with 1,200 milligrams of calcium, compared with women who took just calcium.

Adequate Intakes (AI)

Vitamin D

  • Males (14 yrs. and older)
    • 600 IU (15 mcg)
  • Females (14 yrs. and older)
    • 600 IU (15 mcg)
  • Pregnant females
    • 600 IU (15 mcg)
  • Lactating females
    • 600 IU (15 mcg)
  • Children (1-13 years)
    • 600 IU (15 mcg)
  • Infants (0-12 months)
    • 400 IU (10 mcg)
  • Elderly (>70 years old)
    • 800 IU (20 mcg)
  • Sufficient data to set RDA are unavailable

Tolerable Upper Intake Levels (UL)

  • Adults (9 yrs and older)
    • 4000 IU (100 mcg)
    • Nursing women taking 6000 IU a day, with no adverse effects
      • Observed by Bruce W. Hollis
        • researcher and pediatric nutritionist at the Medical University of South Carolina in Charleston
  • Higher dosages may be necessary if blood tests do not confirm adequate levels
  • Intakes above UL may lead to negative health consequences in some individuals.
    • High vitamin D levels (above 800 IU) with calcium may raise the risk of kidney stones in susceptible people.
    • 4000 to 10000 IUs daily for 3 years can lead to hypercaciuria (elevated calcium levels in urine)
    • nausea and vomiting
    • headaches
    • constipation
    • diarrhea
    • fatigue
    • loss of appetite
    • excessive thirst and urination
    • protein in urine
    • liver and kidney damage
    • Toxic in high doses
  • However others suggest the risk of higher doses of Vitamin d is very low when concurently taking Vitamin K-2 supplementation.


AI & UL Reference

Institute of Medicine, Food and Nutrition Board (2010). Dietary Reference Intakes for Calcium and Vitamin D. Washington, DC: National Academy Press

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