How to calculate a vitamin d3 dose

Written by donna earnest-pravel
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The Food and Nutrition Board of the National Academy of Sciences states that 95mcg of vitamin D is the highest amount of the vitamin an adult can take without experiencing any adverse effects. A study published by the American Journal of Clinical Nutrition in February 2001, determined that a 100mcg dosage of vitamin D3 proved effective and safe in practically all adults measured.

Populations at risk for vitamin D3 deficiency include people older than 50 years old, dark-complexioned people, people living in regions where sunlight is scarce in the winter, people who stay indoors or cover their skin when outdoors, infants whose mothers are vitamin D deficient, people who have difficulty absorbing dietary fat, and obese people.

It is much easier to be deficient in vitamin D3 than overdose on it. Take the following steps to make sure you are getting enough.

Skill level:

Things you need

  • 25 (OH) D test (optional, but recommended)
  • Calendar
  • Journal
  • Sunlight
  • Foods high in vitamin D3
  • Vitamin D3 supplements (1000 or 5000 IU cholecalciferol)
  • Calculator

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  1. 1

    Ask your physician to order a 25 (OH)D test to be sure of your current vitamin D level. Home tests are also available.

  2. 2

    Mark on a calendar 60 days in the future.

  3. 3

    Buy a journal to report any changes in mood, behaviour, or physical changes.

  4. 4

    Note in your journal how much of all available sources for vitamin D you get every day. Sources include sunlight, foods, and supplements.

  1. 1

    Calculate your vitamin D dosage:

    Table for an 68kg./80kg adult:

    Vitamin D Status 25(OH)D Blood levels Correction Dose* Days
    Severely deficient 0-10 ng/ml 7000 IU 60 Deficient 11-20 6000 60 Low-normal 21-32 5500 60 Normal 33-49 0
    Optimum 50-70 0 High, but not toxic 71-150 0 Toxicity possible + 151

  2. 2

    Calculate for your own weight/body mass: Adjusted dose = correction-dose-per-table x body-mass-in-Kg/80 Divide body mass in pounds by 2.2 to find body mass in Kg. Divide this number by 80 to determine how much vitamin D you should supplement.

  3. 3

    Subtract 200 IU. Nutritionists state that approximately 200 IU of vitamin D comes from food sources on a daily basis. If you wish, you may subtract 200 IU from your previous calculation, and get the remainder of your vitamin D from a supplement.

  4. 4

    Check the label of any multivitamin or other nutritional supplement you are taking to see how much vitamin D is listed. Subtract this amount from your previous calculation. If the amount is listed in mcg (micrograms), convert to IU by multiplying the amount listed by 40.

  5. 5

    Return to your doctor after sixty days to determine if your vitamin D levels are higher. Take your journal with you so you have your notes to discuss your results with your doctor.

  1. 1

    Purchase 1000 IU/day vitamin D3 cholecalciferol tablets or 5000 IU/day capsules if you do not want to take a blood test.

  2. 2

    Take 5000 IU/day year round if you have some sun exposure.

  3. 3

    Take at least 5000 IU/day if there is little sunshine where you live, especially if you have darker skin or are overweight.

    The American Journal of Clinical Nutrition currently suggests 10,000 IU/day.

  4. 4

    Document in your journal your supplement amount and the food you eat daily throughout the sixty day period.

    Document the amount of sunlight you get in minutes every day.

    Note any changes you experience during the sixty days: how you slept the previous night, mood, positive or negative thoughts, energy levels, and any physical changes.

  5. 5

    Create a line graph in your journal to chart any positive changes over the sixty day period. This will help you determine if vitamin D supplementation is helping you.

Tips and warnings

  • Make sure your vitamin D is D3 (cholecalciferol, which is bio-identical) and not D2 (ergocalciferol, which is synthetic).
  • Most people get enough vitamin D from sunlight during warmer months. 20-30 minutes sun exposure on bare skin a day is adequate.

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