Effect of four monthly oral vitamin D3 (cholecalciferol) supplementation on fractures and mortality in men and women living in the community: randomised double blind controlled trial
Trivedi et al, has done a service to medicine by using a dose of
cholecalciferol (averaging 800 IU a day) that was slightly more than
homeopathic. As the authors themselves concluded, parathormone levels
were not significantly lower in the vitamin D group suggesting that the
100,000 IU dose every four months was insufficient.
The most important fact anyone should know about vitamin D dose is
that sunbathing for an hour in the summer gives one 10,000 units (1,2).
This fact, if it is accurate, leads one to inescapable conclusions
concerning man's historical "dose" of vitamin D, at least before humans
went inside.
In 1997 the Food and Nutirition Board increased their
recommendations, suggesting elderly persons get 600 IU a day of Vitmain D.
Two former members of that Board (Robert P Heaney and Michael F Holick)
together with collegues(3)recently conducted the first systematic
investigation of the dose-response relation of physiologically doses of
vitamin D and 25-OH vitamin D levels. They concluded "healthy men seem to
use 3000–5000 IU cholecalciferol/day," adding "the recommendations of the
FNB with respect to oral vitamin D input fall into a curious zone between
irrelevance and inadequacy. For those persons with extensive solar
exposure, the recommended inputs add little to their usual daily
production, and for those with no exposure (or those, such as the elderly,
with reduced cutaneous synthesis), the recommended doses are insufficient
to ensure desired 25(OH)D concentrations."
Current fears about vitamin D toxicity are the single greatest
impediment to clinical research concerning vitamin D. Vieth's
comphrehensive 1999 review on the safety of vitamin D (1) should be
required reading in medical school.
The most intriguing aspect of the Trivedi, Doll and Khawir study was
the insignificant, but suggestive, decline in all cause mortality (p value
of .18), including cancer mortality. One can only wonder what they would
have found if they had used physiological doses of vitamin D.
1. Vieth R. Vitamin D supplementation, 25-hydroxyvitamin D
concentrations, and safety. Am J Clin Nutr 1999;69:842-856.
2. Holick MF. Sunlight "D"ilemma: risk of skin cancer or bone disease
and muscle weakness. Lancet 2001;357:4–6.
3. Heaney RP, Davies KM, Chen TC, Holick MF, and Barger-Lux MJ. Human
serum 25-hydroxycholecalciferol response to extended oral dosing with
cholecalciferol. Am J Clin Nutr 2003;77:204-210.
4. Reinhold Vieth, Pak-Cheung R Chan, and Gordon D MacFarlane
Efficacy and safety of vitamin D3 intake exceeding the lowest observed
adverse effect level
Am J Clin Nutr 2001 73: 288-294.
Rapid Response:
Dose of vitamin D
Trivedi et al, has done a service to medicine by using a dose of
cholecalciferol (averaging 800 IU a day) that was slightly more than
homeopathic. As the authors themselves concluded, parathormone levels
were not significantly lower in the vitamin D group suggesting that the
100,000 IU dose every four months was insufficient.
The most important fact anyone should know about vitamin D dose is
that sunbathing for an hour in the summer gives one 10,000 units (1,2).
This fact, if it is accurate, leads one to inescapable conclusions
concerning man's historical "dose" of vitamin D, at least before humans
went inside.
In 1997 the Food and Nutirition Board increased their
recommendations, suggesting elderly persons get 600 IU a day of Vitmain D.
Two former members of that Board (Robert P Heaney and Michael F Holick)
together with collegues(3)recently conducted the first systematic
investigation of the dose-response relation of physiologically doses of
vitamin D and 25-OH vitamin D levels. They concluded "healthy men seem to
use 3000–5000 IU cholecalciferol/day," adding "the recommendations of the
FNB with respect to oral vitamin D input fall into a curious zone between
irrelevance and inadequacy. For those persons with extensive solar
exposure, the recommended inputs add little to their usual daily
production, and for those with no exposure (or those, such as the elderly,
with reduced cutaneous synthesis), the recommended doses are insufficient
to ensure desired 25(OH)D concentrations."
Current fears about vitamin D toxicity are the single greatest
impediment to clinical research concerning vitamin D. Vieth's
comphrehensive 1999 review on the safety of vitamin D (1) should be
required reading in medical school.
The most intriguing aspect of the Trivedi, Doll and Khawir study was
the insignificant, but suggestive, decline in all cause mortality (p value
of .18), including cancer mortality. One can only wonder what they would
have found if they had used physiological doses of vitamin D.
1. Vieth R. Vitamin D supplementation, 25-hydroxyvitamin D
concentrations, and safety. Am J Clin Nutr 1999;69:842-856.
2. Holick MF. Sunlight "D"ilemma: risk of skin cancer or bone disease
and muscle weakness. Lancet 2001;357:4–6.
3. Heaney RP, Davies KM, Chen TC, Holick MF, and Barger-Lux MJ. Human
serum 25-hydroxycholecalciferol response to extended oral dosing with
cholecalciferol. Am J Clin Nutr 2003;77:204-210.
4. Reinhold Vieth, Pak-Cheung R Chan, and Gordon D MacFarlane
Efficacy and safety of vitamin D3 intake exceeding the lowest observed
adverse effect level
Am J Clin Nutr 2001 73: 288-294.
Competing interests:
None declared
Competing interests: No competing interests