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Vitamin D Dosage

Osteoporosis Canada recommends a vitamin D dosage of 800-2,000 IU for people over fifty. Other experts recommend 5,000 IU in the winter for people living in northern regions.

A blood test in the middle of winter is the best way to determine if you are getting enough vitamin D to support calcium absorption. Six months supply of 5,000 IU can cost as little as $7.

Vitamin D is essential for promoting the calcium absorption needed for bone growth and is one of the most important elements in an osteoporosis prevention program.

Research now suggests that vitamin D deficiency is widespread in northern countries and may be a factor not only in the high incidence of osteoporosis but also in various cancers, heart disease, stroke, hypertension, autoimmune diseases and depression.

Many specialists now believe there are no side effects from Vitamin D supplements at intakes below 10,000 IU a day. However, there are certain health conditions where vitamin D supplements are contraindicated and natural sources (or a vitamin D lamp) are the preferred source. Government guidelines for vitamin D are currently under review and are expected to recommend increased vitamin D dosage in response to recent research findings.

VITAMIN D COUNCIL (2,000-5,000 IU daily)

The Vitamin D Council recommends that adults take an average of 5,000 IU daily throughout the year if they have some sun exposure and possibly more if they have little or no sun exposure. The Council suggests that the further you live from the equator, the darker your skin, and/or the more you weigh, the larger vitamin D dosage will be needed to maintain optimal blood levels.

The Council suggests that people living north of the 32 latitude (as compared to the 42 latitude identified by other researchers) may consider the following program to maintain optimal blood levels:

  • Late Fall and Winter: 5,000 IU
  • Early Fall and Spring: 2,000 IU
  • Summer: regular sunbathing may be sufficient

The Council also advises that regular blood tests (25(OH)D tests) are the only way to determine exactly how much vitamin D a person needs to maintain their blood at the recommended level of 125nmol/L (50 ng/mL). This recommendation to monitor vitamin D levels through regular blood tests is now widely supported by most health professionals.

INSTITUTE OF MEDICINE (IOM) (4,000 IU Tolerable Upper Limit)

In 2010, the Institute of Medicine (IOM) raised the safe upper limit of vitamin D from 2000 IU to 4000 IU per day for individuals older than 9 years old.

DR. REINHOLD VIETH (4,000 IU daily)

Dr. Reinhold Vieth of Toronto’s Mt. Sinai Hospital estimates the daily requirement for Vitamin D from all sources at 4,000 IU and he offers compelling evidence that 10,000 IU is a safe and desirable level. (The term "from all sources" includes daily intake from the sun, foods such as cold water fish and from supplements.) Although Vieth believes that 10,000 IU/d of Vitamin D is safe for most people, he also acknowledges that it may not be desirable and could cause an excess of vitamin D in some people.


Dr. David Lescheid, spokesperson for the Canadian Association of Naturopathic Doctors, estimates that 80% of Canadians are vitamin D deficient in the winter and puts the upper limit on vitamin D dosage at 10,000 IU.If you want to read more about vitamin D, this book by Marc Sorenson is recommended by a number of osteoporosis specialists.


The current Adequate Intake (AI) levels for Vitamin D are for 600 IU (international units) daily for everyone up to the age of 70 and 800 IU for people over the age of 70. The recommended upper limit of 2,000 IU daily is now considered outdated by most medical professionals.

The U.S. Food and Drug Administration identified a Daily Value (DV) of 400 IU for vitamin D for all adults and for children over the age of four. The percentage daily value of Vitamin D listed on dairy products, soymilk, cereals and vitamin supplements are based on 400 IU which can be reassuring to consumers but is misleading. A cup of milk reported to provide 45% of your daily requirement is actually providing only 3.6% of your requirement based on the recommendations of the Vitamin D Council and 9% of what Osteoporosis Canada recommends for women over the age of fifty.

Regions north of the 42 latitude (north of Boston, Rome and approximately Beijing) require significantly more vitamin D either through fortified foods or supplements as there is insufficient ultraviolent radiation from the sun during the late fall and winter to allow vitamin D to be produced naturally through the skin. Vitamin D received from sunlight during the summer months will be stored in the body for approximately 60 days... resulting in vitamin D deficiency during the winter just as the flu season arrives.

People who can't tolerate vitamin D supplements (especially those with gastrointestinal problems) may prefer to use a sunlamp. The better lamps are excellent at producing vitamin D and are relatively inexpensive.

To learn about calcium supplements that contain the recommended vitamin D dosage... visit Best Calcium.