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Vitamin D (Index for vitamin D pages)

There is overwhelming evidence as of 2005 that people must get 1,000-2,000 IU of vitamin D. Vitamin D acts through signalling pathways as indicated in reference 1 below. These results were further expanded at the AGE 2006 meeting at Tufts University in Boston. Most people would benefit from 1,000 IU per day, mature adults over 65 from 2,000 IU per day.


Average daily intake

Nutrition Investigator dosage

Upper Limit

men 65+

5 mcg = 200 iu but NIH [27] says 600-800 IU total

2.1 mcg = 84 IU

plus sunshine

2,000 iu

10,000 iu

women 65+

5 mcg = 200 iu but NIH [27] says 600-800 IU total

2.1 mcg = 84 IU

plus sunshine

2,000 iu

10,000 iu

Vitamin: D
Please see information from the Fall/Winter Linus Pauling Institute Newsletter from Dec, 2010.

Blood concentrations of 25-hydroxyvitamin D [25(OH)D]7 above the range of 30 to 50 nmol/L are reported to be associated with optimal bone health (1).

Vitamins D and K help cardiac rhythm. Vitamin K activates the protein osteocalcin, which strengthens bone mass, but decalcifies soft tissues like arterial walls reducing blood pressure. (link: vitamin D and vitamin K; blood pressure; source: LPI meeting 2009; added 6/2009)

August, 2008 - Taking up to 10,000 IU daily is safe. At 40,000 IU daily it is hazardous. A prudent UL (upper limit) is 10,000 IU daily. In Ann Rheum Dis. Published Online First: 12 August 2008, in a study of 9377 participants, it was found that many women at age 45 with chronic widespread pain had low levels of vitamin D. Women with higher levels were 5% less likely to have chronic widespread pain.

February, 2008 -Are vitamin D supplements safe to take?

American Journal of Clinical Nutrition, Vol. 86, No. 6, 1657-1662, December 2007 "concentrations between 20 and 75 nmol/L (vitamin D insufficiency) have more recently been suggested to have an adverse influence on the skeleton (1, 2). Vitamin D insufficiency in the elderly is associated with low bone mass due to secondary hyperparathyroidism and, as a result, a higher incidence of fractures (2-4). It has also been appreciated that sufficient vitamin D may be just as important for other nonskeletal effects, such as the improvement of the immune system and the prevention of certain cancers (5)...There is an emerging consensus that 25(OH)D concentrations >75 nmol/L may be optimal for bone health and extraskeletal effects (7-12). Heaney (13) recently described that an oral intake of 55 µg/d (2200 IU/d) may be required in addition to the prevailing intake of vitamin D to raise 25(OH)D concentrations to near 80 nmol/L or higher. "

Daily Value: 10 mcg Note article below recommends 1,000 iu = 25mcg as of 2004! 2,000 IU for post-menopausal women!

One cup of fortified milk contains 25% of daily value = 1.25 mcg = 50 iu

Hazardous level: 50 mcg

Average intake in US diet: 2.1 mcg (15 minutes sunlight in shorts and T-shirt with no sunscreen daily provides RDA in spring and summer in Wisconsin/Massachusetts)

Function: essential for the proper formation of the skeleton and for mineral homeostasis.

Exposure of the skin to sunlight catalyzes the synthesis of vitamin D.

SENIOR DOSAGE RATIONALE: desirable level is 1,000 iu for elderly. But too much is hazardous. Adjusted for dietary intake. from the 1990 RDAs pg 97 "dietary supplements may be detrimental for the normal child or adult who drinks at least two glasses of vitamin D-fortified milk per day". However, new evidence indicates we definitely need more vitamin D. I currently (6/1/05) take 800 iu per day.

1. Vitamin D: More than bone health, based on remarks by Dr. Michael F. Hollick, Prof of Medicine, Physiology and Biophysics at Boston Univ. School of Medicine, Director of Osteoporosis Center at BU.
 " The Importance of Vitamin D in prevention of osteoporosis and other chronic diseases," presented at the Linus Pauling Institute "Diet and Optimal Health" conference, Portland, OR, May 20, 2005
He was critical of multivitamins: "multivitamin is bad due to vitamin A"
In US in places like Boston and Portland, we can't make vitamin D from sunlight in the fall and winter.  But he stated 40-60% of fibromyalgia is actually lack of vitamin D and misdiagnosed by medical experts.  People would benefit most from a dosage of 50,000 IU taken every other week; a dose of 1,000 iu per day also works [one can get 400 iu pills at most supermarkets, and take two pills a day].  Sunbathing to a light pinkness on the skin provides as much vitamin D as consuming 10,000-25,000 IU.  However, sun screen reduces that production by 97.5%.  Another surprising comment was that sun exposure actually reduces incidence of melanoma! (But he did not comment on other skin cancers - there are lots of others).  50% of elderly are vitamin D deficient, 32% of students age 18-29, 41% of Afro-Americans in Boston.
    Scientists have now worked out many of the signaling pathways of vitamin D, and done many epidemiologic studies based on the Nurses and Physician's Health Studies.  Vitamin D reduces heart disease by 20-40%, and causes many cancer cells to revert to being normal cells by activating dormant genes necessary for healthy cell function.
  In addition to Hollick's remarks, people have asked about toxicity from high doses.  Here is information for the U.S. Government information page at []. "Sun exposure is unlikely to result in vitamin D toxicity [60]. Diet is also unlikely to cause vitamin D toxicity, unless large amounts of cod liver oil are consumed. Vitamin D toxicity is much more likely to occur from high intakes of vitamin D in supplements. The Food and Nutrition Board of the Institute of Medicine has set the tolerable upper intake level (UL) for vitamin D at 25 É g (1,000 IU) for infants up to 12 months of age and 50 É g (2,000 IU) for children, adults, pregnant, and lactating women [4]."
  At extremely high doses, far in excess of 2,000 IU, " Vitamin D toxicity can cause nausea, vomiting, poor appetite, constipation, weakness, and weight loss [59]. It can also raise blood levels of calcium [6], causing mental status changes such as confusion. High blood levels of calcium also can cause heart rhythm abnormalities. Calcinosis, the deposition of calcium and phosphate in the body's soft tissues such as the kidney, can also be caused by vitamin D toxicity [4]."

2. Vitamin D: importance in the prevention of cancers, type 1 diabetes, heart disease, and osteoporosis Michael F Holick Am. J. Clinical Nutrition,  Mar 2004;  79:  362 - 371. Vitamin D deficiency is prevalent in infants who are solely breastfed and who do not receive vitamin D supplementation and in adults of all ages who have increased skin pigmentation or who always wear sun protection or limit their outdoor activities. Vitamin D deficiency is often misdiagnosed as fibromyalgia… Studies in both human and animal models add strength to the hypothesis that the unrecognized epidemic of vitamin D deficiency worldwide is a contributing factor of many chronic debilitating diseases. ...The recommended adequate intakes for vitamin D are inadequate, and, in the absence of exposure to sunlight, a minimum of 1000 IU vitamin D/d is required to maintain a healthy concentration of 25(OH)D in the blood.

3. Heike A Bischoff-Ferrari et al, Association between serum concentrations of 25-hydroxyvitamin D3 and periodontal disease in the US population
Am J Clin Nutr 2004 80: 108-113

Conclusions: Low [vitamin D] serum 25(OH)D3 concentrations may be associated with Periodontal [gum] disease independently of bone mineral density [for people over age 50]. Given the high prevalence of periodontal disease and vitamin D deficiency, these findings may have important public health implications.


Food and Nutrition Board, Recommended Dietary Allowances, 10th edition, National Academy Press,

Washington, DC, 1989

"Establishing an RDA for vitamin D is difficult because exposure to sunlight results in synthesis of

vitamin D by the skin. People regularly exposed to sunlight, under appropriate conditions, have no

dietary requirement for vitamin D... Vitamin D is potentially toxic, especially for young children.

The effects...include hypercalcemia and hypercalcuria, leading to deposition of calcium in soft

tissues and irreversible renal and cardiovascular damage...dietary supplements may be detrimental

for the who drinks at least two glasses of vitamin D-fortified milk per day." "dietary

supplements may be detrimental for he normal child or adult who drinks at least two glasses of

vitamin D-fortified milk per day" pg 97

Kearney, J, Giovannucci, E., Rimm, EB, Ascherio, A, Stampfer, MJ, Colditz, GA, Wing, A, Kampman, E.

and Willett, WC. "Calcium, vitamin D, and dairy foods and the occurrence of colon cancer in men", Am. J.

Epidemiol. 143(9): 907-17, (1996).

"intake of calcium from foods and supplements [in mature men] was inversely associated with colon

cancer risk"


"The National Osteoporosis Foundation recommends 1,000 to 1,500 mg of calcium a day plus

400 to 800 IU of vitamin D to help absorb the calcium and a minimum of 30 minutes of weight-

bearing exercise".

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