VITAMIN D DOSAGE
There is growing support for a daily vitamin D dosage of 1,000-2,000 IUs from all sources (including sunlight, food and supplements) and possibly 5,000 IUs in the winter for people living in northern regions.
To view comments about vitamin D dosage and supplements visit our Vitamin D Forum. Vitamin D is essential for promoting the calcium absorption needed for bone growth and remodeling and is one of the most important elements in an osteoporosis prevention program.
As the importance of Vitamin D becomes better understood, there is significant controversy over vitamin D dosage and the target blood levels required for healthy bone development and general well-being. Research now suggests that vitamin D deficiency is widespread in northern countries and may be a factor in various cancers as well as 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. Government guidelines for vitamin D are currently under review and are expected to recommend increased vitamin D dosage in response to recent research findings. Although the new government guidelines are expected in 2010, the debate over optimal vitamin D dosage will likely continue. More research is needed on the many factors that impact vitamin D deficiency including ethnicity, gender, region of residence; age group and medical conditions. A review of current recommendations will provide a useful context for designing an osteoporosis prevention program while the debate continues.
ADEQUATE INTAKE (AI) AND DAILY VALUE (DV) LEVELS OF VITAMIN D (200-400 IU daily) The current Adequate Intake (AI) levels for Vitamin D were established in 1997 by the U.S. Institute of Medicine of the National Academy of Sciences. (These recommendations are currently under review.) The recommendations are for 200 IU (international units) daily for everyone under the age of 50, including pregnant/lactating women. For all individuals 50-70 years-old, 400 IU is recommended and for those 70 years-old 600 IU is suggested. The recommended upper limit of 2,000 IU daily is now considered outdated by most medical professionals.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-although most experts now consider this insufficient to protect our bone health. 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. NATIONAL OSTEOPOROSIS FOUNDATION RECOMMENDATIONS (400-1,000 IU daily) The U.S. National Osteoporosis Foundation (NOF) recommends that adults under 50 get 400-800 IU of vitamin D daily and adults 50 and over get 800-1,000 IU. It also acknowledges that some people may need more vitamin D. CANADIAN CANCER SOCIETY ( 1,000 IU daily )
The Canadian Cancer Society recommends that adults take 1,000 IU of vitamin D daily throughout the winter months and adults with a higher risk of vitamin D deficiency (those who are older, have dark skin, spend more time indoors, or stay covered up outdoors) take the supplement year round. Vitamin D experts vary in their recommendations regarding the optimal vitamin D dosage but most are now recommending higher levels than currently suggested by the National Osteoporosis Foundation, Food and Drug Administration and Canadian Cancer Society.
DR. MICHAEL HOLICK (1,000-2,000 IU daily)
Dr. Michael Holick, who is the author of The UV Advantage, encourages people to get as much of their vitamin D from the sun as possible. But for people with limited exposure to the sun, he recommends 1,000 IU of vitamin D through supplements and for people living north of Atlanta or Boston he recommends that a vitamin D dosage of 2,000 IUs will help to maintain optimal blood levels.
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.
CANADIAN ASSOCIATION OF NATUROPATHIC DOCTORS (10,000 IU)
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.
VITAMIN D COUNCIL (2,000-5,000 IU daily) The Vitamin D Council recommends that people take an average of 5,000 IU a day, year-round, 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:
The Council also advises that regular blood tests (25(OH)D tests) are the only way to see how much vitamin D is needed to maintain the blood at its recommended level of 50 ng/mL. This recommendation to monitor vitamin D levels through regular blood tests is now widely supported by most health professionals.
To learn about calcium supplements that contain the recommended vitamin D dosage....visit Best Calcium.
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