"So it is not just autistic children that are being harmed by vitamin A.
Avoid cod liver oil like the poison it is and check your multivitamins. Life
Extension Foundation just reformulated their multivitamin to contain only 500 IU
of preformed retinol. And, I am happy to report that Purity Products, which
markets my vitamin D, has no preformed retinol at all in any of their
multivitamins, only beta carotene. Purity has also stopped selling cod liver
oil. Now, if only Carlson, Solgar, Nature's Way, and other companies would stop
selling cod liver oil and stop selling their concentrated vitamin A supplements
to a country whose problem is widespread sub-clinical vitamin A toxicity, I'd be
a happier agitator. "
and
"However, the elderly of many countries, not just Nordic countries, were raised
on cod liver oil and I suspect that a sizable number of Americans continue to
take cod liver oil as they age. While cod liver oil from the 1980s and 90s had
higher amounts of vitamin D than does modern cod liver oil, it still had toxic
amounts of A. I suspect if authors of the above ten studies had controlled for
cod liver oil intake, they would have found that high retinol intake was
blocking the cancer-preventing effects of vitamin D. "
http://thenaturaladvocate.blogspot.com/2010/02/remarkable-paper-in-british-medical.html
Sunday, February 28, 2010
Remarkable Paper in British Medical Journal - vitamin D
The Vitamin D Newsletter
February 28, 2010
This is a periodic newsletter from the Vitamin D Council, a non-profit trying to
end the epidemic of vitamin D deficiency. If you want to unsubscribe, go to the
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A few weeks ago, the British Medical Journal published a remarkable paper,
remarkable that it studied more than 500,000 subjects, remarkable that it had 56
(fifty-six) authors, remarkable that it confirmed low vitamin D levels obtained
in the past are a risk factor for developing colon cancer in the future.
However, the most remarkable part of the paper is that the 46 scientists
minimized the true significance of their own research. They found that vitamin
A, even in relatively low amounts, appears to thwart vitamin D's association
with reduced rates of colon cancer.
Jenab M et
al. Association between pre-diagnostic circulating vitamin D concentration and
risk of colorectal cancer in European populations: a nested case-control study.
BMJ 2010;340:b5500
This is a prospective nested case-controlled study, which means it uses
subject's vitamin D blood samples obtained and frozen in the past and then
reviews their medical records into the future to see who gets colon cancer,
comparing the study subjects to similar members of the group that did not get
the illness. Dr. Mazda Jenab and his 45 colleagues from the International Agency
for Research on Cancer confirmed that low vitamin D levels are a risk for colon
cancer in a dose response manner; those with the highest levels were about twice
as less likely to develop colon cancer compared to those with the highest
levels.
However, hidden on page eight is one sentence and a small table, which shows
that the benefits of vitamin D are almost entirely negated in those with the
highest vitamin A intake. And the retinol intake did not have to be that high in
these older adults to begin to negate vitamin D's effects, about 3,000 IU/day.
Remember, young autistic children often take 3,500 IU of retinol a day in their
powdered multivitamins, which doesn't count any additional vitamin A given in
high single doses.
This is the largest study to date showing vitamin A blocks vitamin D's effect
and explains some of the anomalies in other papers on vitamin D and cancer. For
example, Dr. Rachael Stolzenberg-Solomon of the NIH conducted two similar
studies on pancreatic cancer, with startling different results. Her first paper
showed high vitamin D levels tripled the subsequent risk of pancreatic cancer,
her second paper showed no effect. The difference, the first was conducted in a
cod liver oil country, Finland, the second in the USA.
Stolzenberg-Solomon
RZ et al. A prospective nested case-control study of vitamin D status and
pancreatic cancer risk in male smokers. Cancer Res. 2006 Oct 15;66(20):10213-9.
Stolzenberg-Solomon
RZ, et al. Serum vitamin D and risk of pancreatic cancer in the prostate, lung,
colorectal, and ovarian screening trial. Cancer Res. 2009 Feb 15;69(4):1439-47.
Prostate cancer is another good example; ten similar studies have been conducted
on vitamin D blood levels and the risk of subsequent prostate cancer. Dr. Lu Yin
of the German Cancer Research Center reviewed them in detail. Eight of the
studies found no relationship but two studies found a U shaped curve, that is,
an increased risk of prostate cancer at both lower and higher vitamin D levels.
You guessed it; both of these studies were from Nordic countries where cod liver
oil consumption is rampant.
Yin L et al.
Meta-analysis of longitudinal studies: Serum vitamin D and prostate cancer risk.
Cancer Epidemiol. 2009 Dec;33(6):435-45.
So why is there no relationship between vitamin D levels and the future risk of
prostate cancer? All the subjects had their vitamin D levels checked in the late
1980s or 1990s, well into the sun-scare but before the vitamin D revolution. So
how did these older people get high levels of vitamin D back then?
Multivitamins? No, they only contained a meaningless 400 IU. Vitamin D
supplements? No, they were not widely available back then and only contained a
meaningless 200 to 400 IU of vitamin D if available. Sunshine? Maybe, but I
doubt it. Studies have shown that the elderly were the first to abide by
sun-avoidance advice; anyway, the elderly lose the ability to make vitamin D
from sunshine; it takes the elderly up to ten times more time in the sun that
the young to make an equivalent amount of vitamin D.
However, the elderly of many countries, not just Nordic countries, were raised
on cod liver oil and I suspect that a sizable number of Americans continue to
take cod liver oil as they age. While cod liver oil from the 1980s and 90s had
higher amounts of vitamin D than does modern cod liver oil, it still had toxic
amounts of A. I suspect if authors of the above ten studies had controlled for
cod liver oil intake, they would have found that high retinol intake was
blocking the cancer-preventing effects of vitamin D.
I say this because one author has controlled for retinol intake and the
pre-cancerous condition, colon adenomas. Dr. Kyungwon Oh, of the Korea Centers
for Disease Control and Prevention, working with Harvard epidemiologists, found
that high retinol intake completely thwarted the beneficial effects of vitamin
D, stating, "a higher retinol intake, approximately > 4,800 IU/day, appears to
counter the beneficial effect of vitamin D . . ." In other words, exactly what
the British Medical Journal paper found with colon cancer.
Oh K et al.
Calcium and vitamin D intakes in relation to risk of distal colorectal adenoma
in women. Am J Epidemiol. 2007 May 15;165(10):1178-86.
Let"s look at Dr. Pamela Goodwin"s study from the University of Toronto that
studied breast cancer survival. This a very different study as it looked at
vitamin D levels obtained after the diagnosis of breast cancer and subsequent
survival in 535 Toronto women between 1989 and 1996. Vitamin D levels ranged
from 3 ng/ml to 70 ng/ml. The women with the lowest levels were about twice as
likely to die and to suffer distant cancer recurrence compared those with the
highest levels. Ten year survival was 85% for those in the upper one-third of
vitamin D levels compared to 74% in the lower one-third. However, the data
suggested a U shaped curve for the women with levels above 40 ng/ml, that is, a
higher risk of dying, but it was not statistically significant.
Goodwin PJ
et al. Prognostic effects of 25-hydroxyvitamin D levels in early breast cancer.
J Clin Oncol. 2009 Aug 10;27(23):3757-63.
Again, let"s ask where women would get levels above 40 ng/ml in Toronto between
1989 and 1996? Sunshine? We know the answer is no as the authors found no
seasonal variation in 25(OH)D levels in the 535 women, even in the women with
the highest levels. So where did blood levels of 40-70 ng/ml come from in the
early 1990s? Vitamin D supplements were not widely available in the early 1990s,
and only contained meaningless doses when available. As sunshine was ruled out,
they could only have gotten it from cod liver oil. I have emailed Dr. Pamela
Goodwin, lead author, asking how hard it would be to see if cod liver oil use
was asked about in the dietary questionnaire and if she could control for cod
liver oil intake. She did find retinol intake was associated with higher vitamin
D levels but I am particularly interested in cod liver oil intake in women with
vitamin D levels above 40 ng/ml.
It's not just in breast cancer that vitamin D levels appear to have a treatment
effect; it's in lung, prostate and colon cancer as well. Again, these are
studies of people diagnosed with cancer to see if high vitamin D levels at the
time of diagnosis are associated with improved survival.; that is, do high
vitamin D levels have a treatment effect? On average, those with the highest
vitamin D levels at time of diagnosis lived 2 or 3 times longer. One has to ask
how high vitamin D levels are associated with greatly improved survival once you
get cancer but a higher risk of getting cancer in the first place. That requires
some gymnastic thinking and acrobatic basic science.
Zhou W et
al. Circulating 25-hydroxyvitamin D levels predict survival in early-stage
non-small-cell lung cancer patients. J Clin Oncol. 2007 Feb 10;25(5):479-85.
Ng K et al.
Clin Oncol. 2008 Jun 20;26(18):2984-91. Circulating 25-hydroxyvitamin D levels
and survival in patients with colorectal cancer. J Clin Oncol. 2008 Jun
20;26(18):2984-91.
Tretli S et
al. Association between serum 25(OH)D and death from prostate cancer. Br J
Cancer. 2009 Feb 10;100(3):450-4.
Remember, studies of vitamin D levels and subsequent risk of cancer are only one
type of epidemiological study. Studies of latitude and cancer are quite clear,
the less sunshine the higher the cancer risk. Studies of dietary vitamin D
intake and cancer are also mostly supportive but such studies are limited by the
tiny doses people get in their diets.
So it is not just autistic children that are being harmed by vitamin A. Avoid
cod liver oil like the poison it is and check your multivitamins. Life Extension
Foundation just reformulated their multivitamin to contain only 500 IU of
preformed retinol. And, I am happy to report that Purity Products, which markets
my vitamin D, has no preformed retinol at all in any of their multivitamins,
only beta carotene. Purity has also stopped selling cod liver oil. Now, if only
Carlson, Solgar, Nature's Way, and other companies would stop selling cod liver
oil and stop selling their concentrated vitamin A supplements to a country whose
problem is widespread sub-clinical vitamin A toxicity, I'd be a happier
agitator.
John Cannell, MD
Executive Director
Vitamin D Council
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