Re: Vitamin could stop common cancers

27 Dec 2005 14:47:13 -0800 in article
<[email hidden]> "Roman Bystrianyk"

Quoted message said:

"Vitamin could stop common cancers", Daily Mail, December 27, 2005,
Link:
http://www.dailymail.co.uk/pages/live/articles/news/news.html?in_article_id=372693&in_page_id=1770

A large daily dose of vitamin D can lower the risk of developing common
cancers by as much as 50%, scientists said.

Researchers found that the "natural" form of the vitamin, known as D3,
can dramatically reduce the chances of developing breast, ovarian and
colon cancer, as well as others.

Taking 1,000 international units (IU) of the vitamin daily could lower
an individual's cancer risk by 50%, they said.

Such large doses of vitamin D must be treated with caution. More than
2,000 IU a day can lead to the body absorbing too much calcium, and
possible damage to the liver and kidneys.

It's true that current tolerable upper intake limit is 2000 IU/d, but most
prominent vitamin D researchers now agree that this limit is too low by at
least 5-fold, and suggest that _optimal_ intake could be approximately 4000
IU/D, see

Vieth R.
Vitamin D supplementation, 25-hydroxyvitamin D concentrations, and
safety.
Am J Clin Nutr. 1999 May;69(5):842-56. Review.
PMID: 10232622 [PubMed - indexed for MEDLINE]
<http://www.ajcn.org/cgi/content/full/69/5/842>

"For adults, the 5-microg (200 IU) vitamin D recommended
dietary allowance may prevent osteomalacia in the absence
of sunlight, but more is needed to help prevent
osteoporosis and secondary hyperparathyroidism. Other
benefits of vitamin D supplementation are implicated
epidemiologically: prevention of some cancers,
osteoarthritis progression, multiple sclerosis, and
hypertension. Total-body sun exposure easily provides the
equivalent of 250 microg (10000 IU) vitamin D/d,
suggesting that this is a physiologic limit. Sailors in
US submarines are deprived of environmentally acquired
vitamin D equivalent to 20-50 microg (800-2000 IU)/d. The
assembled data from many vitamin D supplementation
studies reveal a curve for vitamin D dose versus serum
25-hydroxyvitamin D [25(OH)D] response that is
surprisingly flat up to 250 microg (10000 IU) vitamin
D/d. To ensure that serum 25(OH)D concentrations exceed
100 nmol/L, a total vitamin D supply of 100 microg (4000
IU)/d is required. Except in those with conditions
causing hypersensitivity, there is no evidence of adverse
effects with serum 25(OH)D concentrations <140 nmol/L,
which require a total vitamin D supply of 250 microg
(10000 IU)/d to attain. Published cases of vitamin D
toxicity with hypercalcemia, for which the 25(OH)D
concentration and vitamin D dose are known, all involve
intake of > or = 1000 microg (40000 IU)/d. Because
vitamin D is potentially toxic, intake of >25 microg
(1000 IU)/d has been avoided even though the weight of
evidence shows that the currently accepted, no observed
adverse effect limit of 50 microg (2000 IU)/d is too low
by at least 5-fold."

Heaney RP, Davies KM, Chen TC, Holick MF, Barger-Lux MJ.
Human serum 25-hydroxycholecalciferol response to extended oral
dosing with cholecalciferol.
Am J Clin Nutr. 2003 Jan;77(1):204-10. Erratum in: Am J Clin Nutr.
2003 Nov;78(5):1047.
PMID: 12499343 [PubMed - indexed for MEDLINE]
<http://www.ajcn.org/cgi/content/full/77/1/204>

"Widespread supplementation with vitamin D has important
public health implications. The FNB proposed estimates,
for the first time, of tolerable upper input levels for
nutrients, particularly for the micronutrients that can
be incorporated into foods as fortificants or ingested as
nutritional supplements (1). Evidence available to the
FNB with regard to vitamin D toxicity at inputs of the
magnitude employed in this study was scant in the
extreme. Nevertheless, on the basis of sporadic reports
(of uncertain quality) of hypercalcemia and
hypercalciuria, the panel settled on a conservative
tolerable upper input level of 2000 IU/d for vitamin D
(1), recognizing that many persons, especially those who
work outdoors in the summer, almost certainly had higher
inputs without apparent adverse effect.

We agree completely with Vieth (9) that the evidence
available today indicates that a value of 2000 IU/d for
the tolerable upper input level is too low. As already
noted, the data presented here indicate an average daily
need perhaps twice that amount. Note that, in our study,
20 wk of supplementation at 5500 and 11 000 IU/d,
starting from a status of relative vitamin D repletion,
produced no elevation of serum calcium above the upper
limits of normal in any subject. Note also that the
highest mean 25(OH)D3 values reached were {approx}160 and
{approx}220 nmol/L, respectively. By contrast, a case
report (21) suggested that serum 25(OH)D concentrations
between 125 and 225 nmol/L produce bone loss. Although
that study was almost certainly in error on technical
grounds, the fact that it could be published with an
accompanying, supportive editorial (22) underscores both
the almost complete absence of basic data in this field
and the need to obtain such data. This present report
constitutes one step in providing this missing
information."

Vieth R, Chan PC, MacFarlane GD.
Efficacy and safety of vitamin D3 intake exceeding the lowest
observed adverse effect level.
Am J Clin Nutr. 2001 Feb;73(2):288-94.
PMID: 11157326 [PubMed - indexed for MEDLINE]
<http://www.ajcn.org/cgi/content/full/73/2/288>

Vieth R.
Why the optimal requirement for Vitamin D3 is probably much higher
than what is officially recommended for adults.
J Steroid Biochem Mol Biol. 2004 May;89-90(1-5):575-9. Review.
PMID: 15225842 [PubMed - indexed for MEDLINE]
<http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=15225842>

Zittermann A.
Vitamin D in preventive medicine: are we ignoring the evidence?
Br J Nutr. 2003 May;89(5):552-72. Review.
PMID: 12720576 [PubMed - indexed for MEDLINE]
<http://thesius.ingentaselect.com/vl=701474/cl=159/nw=1/rpsv/ij/cabi/00071145/v89n5/s2/p552>

--
Matti Narkia