Recent research
claims “high dose” vitamin D supplementation did not result in a lower
incidence of cancer or cardiovascular events than placebo
The “high dose”
given in this trial was a mere 2,000 international units (IUs) a day,
which is still only a quarter or less of what many need to raise their
blood level into a protective range
The study did
not test and track participants’ vitamin D blood levels, which is the
only way to ensure sufficiency and adherence to the protocol
Cancer is a
slow-growing disease and effects of nutritional intervention typically
only become evident after several years. When the first two years of
follow-up data were excluded, people who took 2,000 IUs of vitamin D3
per day had a 25 percent lower risk of cancer in the years following
(years three through five)
Many need
upward of 10,000 IUs a day in order to achieve a blood level of 40 ng/mL
(100 nmol/L) or higher, which is the bottom cutoff for health and
disease prevention. Ideally, you’ll want a level between 60 and 80 ng/mL
(150 and 200 nmol/L)
The effectiveness of vitamin D supplementation has again been questioned with negative headlines1,2
trumpeting its failure to prevent cancer and cardiovascular disease.
What most researchers and journalists fail to address, however, is the
fact that:
The "high dose" given in this trial was a mere 2,000 international
units (IUs) a day, which is still only a quarter or less of what many
need to raise their blood level into a protective range
They did not test and track participants' vitamin D blood levels, which is the only way to ensure sufficiency
Based on those two factors alone, a negative result is precisely what
one would predict. Still, despite such limitations, the study actually
found some rather remarkable benefits that were simply glossed over.
In fact, had it been a drug trial, vitamin D would likely have been
declared a miracle drug against both cancer and cardiovascular disease,
based on the findings. This is the kind of perversion of science and
selective reporting that shackles public health.
VITAL Study Conclusions
The study3,4
in question, which was in part funded by the U.S. National Institutes
of Health, was published in the January 2019 issue of the New England
Journal of Medicine (NEJM). (A second study5 compared omega-3 supplementation against placebo for the same endpoints.) As detailed in the vitamin D paper, the study was:
"[A] nationwide, randomized, placebo-controlled trial, with a
two-by-two factorial design, of vitamin D3 (cholecalciferol) at a dose
of 2000 IU per day6 and marine n−3 (also called omega-3) fatty acids at a dose of 1 gram per day7
for the prevention of cancer and cardiovascular disease among men 50
years of age or older and women 55 years of age or older in the United
States.
Primary end points were invasive cancer of any type and major
cardiovascular events (a composite of myocardial infarction, stroke or
death from cardiovascular causes). Secondary end points included
site-specific cancers, death from cancer and additional cardiovascular
events."
In conclusion, the authors determined that "Supplementation with
vitamin D did not result in a lower incidence of invasive cancer or
cardiovascular events than placebo."
What the VITAL Data Actually Reveals
However, as noted by GrassrootsHealth,8 a nonprofit public health research organization dedicated to moving public health messages regarding vitamin D and omega-3
from research into practice, “when the separate types of heart disease
or death from cancer were analyzed, there were 30 different very
significant results,” summarized in the graph9 below.
Importantly, when the researchers excluded data from the first two
years of supplementation, cancer mortality "was significantly lower with
vitamin D than with placebo."10
The reason this is important is because cancer
is a slow-growing disease and effects of nutritional intervention
typically only become evident after several years. It's unreasonable to
think you can take a supplement and within weeks or months see a drastic
difference in health outcomes. The paper states that clearly, and adds:
"Supplemental vitamin D also did not reduce the occurrence of
breast, prostate or colorectal cancers. However, there was a suggestive
17 percent reduction in cancer deaths, which became a 25 percent
reduction in analyses that excluded the first two years of follow-up."
Let me repeat those two points for clarity:
While incidence of breast, prostate and colorectal cancers were
unaffected, those who took a non-ideal dose of vitamin D3 supplements
still had a 17 percent lower risk of actually dying from those cancers
When the first two years of follow-up data were excluded, people who
took a mere 2,000 IUs of vitamin D3 per day had a 25 percent lower risk
of cancer in the years following (years three through five)
How is this not good news? Again, let's remember that 2,000 IUs is
really insufficient for most people, yet even at this insufficient
dosage, the risk of cancer was cut by 25 percent.
For Most, 2,000 IUs a Day Is Suboptimal for Cancer Prevention
In years past, it was widely believed that 4,000 IUs was the upper safe limit, above which you risked vitamin D toxicity,
but studies have since refuted this, showing there's no risk of
toxicity until you hit 30,000 IUs a day, or a blood level of 200 ng/ml
(500 nmol/L).11 Still, the misconception persists.
A significant body of research shows many need upward of 10,000 IUs a
day in order to achieve a blood level of 40 ng/mL (100 nmol/L) or
higher, which is the bottom cutoff for health and disease prevention.
Ideally, you’ll want a level between 60 and 80 ng/mL (150 and 200
nmol/L). This is where the majority of health benefits become really
apparent.
As noted in a 2009 study12
on athletic performance and vitamin D, "At levels below 40 to 50 ng/mL
the body diverts most or all of the ingested or sun-derived vitamin D to
immediate metabolic needs, signifying chronic substrate starvation
(deficiency)."
As noted earlier, the VITAL study did not use vitamin D blood levels
as the marker for deficiency or sufficiency, and this is perhaps the
most significant problem with this study. Blood levels were only
measured in a subgroup of 1,644 participants (out of 25,871) after the
first year of daily supplementation.
In this group, the mean vitamin D blood level increased from 29.8
ng/mL (74 nmol/L) at baseline to 41.8 ng/mL (104 nmol/L). In other
words, most of those taking vitamin D supplements had barely adequate
vitamin D levels, and were still significantly short of having ideal
blood levels — levels at which research shows the risk of cancer is cut
up to 80 percent.
Why You Cannot Trust Studies That Base Results on Dosage Rather Than Blood Measurement
This certainly is not the first time studies have claimed vitamin D supplementation is useless. Last year, a meta-analysis13
concluded once-a-month high-dose vitamin D supplementation had no
impact on cancer risk. Here, participants received an initial bolus dose
of 200,000 IUs of vitamin D, followed by a monthly dose of 100,000 IUs
(so-called pulsed or pulsatile dosing) for a median of three years.
While the media played this up as a finding contradicting
recommendations to optimize your vitamin D to lower your cancer risk, it
really only made a case against once-a-month mega-dosing. As noted by
GrassrootsHealth scientists, for optimal results, you need to supplement
frequently (ideally daily) and focus on the achieved serum level, not
the dosage.
What's more, 100,000 IUs per month actually only comes out to about
3,000 IUs per day, which again is far below what most adults need to
raise their vitamin D serum level into the protective range of 60 to 80
ng/mL, with 40 ng/mL being the low-end cutoff for sufficiency.
Indeed, this analysis noted the mean baseline vitamin D concentration
was just over 26 ng/mL, and the mean follow-up level was just 20 ng/mL
higher in the supplement group than the placebo group that received no
vitamin D.
As in the current NEJM study, participants' vitamin D levels were
also not measured regularly throughout the study, and the association
with cancer was not analyzed by serum level but by daily dosage.
This point really cannot be stressed enough: The key factor is not
how much vitamin D you take but whether or not your blood level of
vitamin D is within the "Goldilocks' zone" of 60 to 80 ng/mL, and the
only way to ascertain that is through blood testing.
How to Assess Study Quality
GrassrootsHealth scientists have also argued that pulsatile dosing at
intervals greater than two weeks may actually cause a form of vitamin D
deficiency at the cellular level.
According to GrassrootsHealth, to accurately ascertain the benefit of
vitamin D in any given trial, researchers must track not only the
baseline and final vitamin D serum level plus the dose given, but also
the form (vitamin D2 versus D3) and the dosing interval.
Adherence to protocol is also measured by blood level. If a
participant's blood level doesn't change, you know that individual was
probably not taking the supplement as instructed, rendering their result
null and void.
All of these factors can influence the results, and it's important to
get them all right. Identifying the ideal parameters are all part of
what GrassrootsHealth is doing. Another study, published in 2017,
claimed it found "no case" for vitamin D supplementation during
pregnancy.14
In reality, it found seven positive outcomes,15
including increased birth weight, a 40 percent reduction in gestational
diabetes, an 18 percent reduction in preeclampsia and a 17 percent
reduction in gestational hypertension.
What this study failed to find was a reduction in preterm birth, and
this was ultimately translated into headlines that made it appear as
though pregnant women have no need for vitamin D supplementation! In
reality, nothing could be further from the truth.16,17
So, in summary, when evaluating vitamin D research, the following
parameters are what you're looking for in a high-quality study, as
without these, the results are likely to be significantly flawed and
likely negative:
• Supplementation should be frequent, ideally daily — Bolus doses given at intervals greater than two weeks are likely to be ineffective. According to Carole Baggerly,
director and founder of GrassrootsHealth, pulsatile dosing at intervals
greater than two weeks may actually cause a form of vitamin D
deficiency at the cellular level. • Dosage, baseline and final vitamin D serum level must all be tracked — Most studies fail in this regard, as most only track dosage and not serum level, which is the most crucial parameter of all.
In short, it doesn't matter how large or small the dose is, as long
as it gets the participants into a specific blood level range, as the
individual response to any given dose varies widely, depending on
several different factors, including intake of other nutrients (such as
magnesium), age, ethnicity, body weight and amount of sun exposure. • The form of vitamin D must be identified — Are they using vitamin D2 or D3? And are they tracking sun exposure, which is the primary way your body produces vitamin D?
There's Strong Evidence Vitamin D Lowers Your Chronic Disease Risk
Vitamin D, a steroid hormone, is vital for the prevention of many chronic diseases, including but not limited to:
Type 2 diabetes
Age-related macular degeneration (the leading cause of blindness)
Well over a dozen different types of cancer, including skin cancer — the very cause of concern that has led so many to avoid the sun exposure necessary for vitamin D production
In the case of heart disease, vitamin D plays a vital role in protecting and repairing damage to your endothelium.18
It also helps trigger production of nitric oxide — which improves blood
flow and prevents blood clot formation — and significantly reduces
oxidative stress in your vascular system, all of which are important to
help prevent the development and/or progression of cardiovascular
disease.
Just last year, a Norwegian study19
published in The Journal of Clinical Endocrinology and Metabolism found
"a normal intake of vitamin D" significantly reduces your risk of death
if you have cardiovascular disease.20
According to vitamin D researcher Dr. Michael Holick, vitamin D deficiency
— defined as a level below 20 ng/mL (50 nmol/L) — can also raise your
risk of heart attack by 50 percent, and if you have a heart attack while
vitamin D deficient, your risk of dying is nearly guaranteed.
Vitamin D also has powerful infection-fighting abilities, making it a useful aid in the treatment of tuberculosis, pneumonia, colds and flu,
while maintaining a healthy vitamin D level will typically prevent such
infections from taking root in the first place. Studies have also
linked higher vitamin D levels with lowered mortality from all causes.21,22,23
A Majority of Breast Cancer Cases Could Be Avoided by Raising Vitamin D Levels Among the General Public
Importantly, the ongoing research by GrassrootsHealth has firmly
established that 20 ng/mL, which is conventionally considered the cutoff
for sufficiency, is nowhere near sufficient for optimal health and
disease prevention.
As mentioned, 40 ng/mL (100 nm/L) appears to be at the low end of
optimal, and most participants in the featured NEJM study were likely
hovering right around this low-end blood level (based on measurements
from a very limited subgroup).
Still, recall the risk of cancer in Years 3 through 5 among those who
supplemented with 2,000 IUs a day (thereby reaching a mean blood level
of just under 42 ng/mL) went down by 25 percent. GrassrootsHealth
research shows the ideal protective range is between 60 and 80 ng/mL
(150 to 200 nm/L), and the higher the better within this range.
Research has actually demonstrated that most cancers occur in people with a vitamin D blood level between 10 and 40 ng/mL.24,25
Meanwhile, research shows women with vitamin D levels above 60 ng/mL
have an 83 percent lower risk of breast cancer than those with levels
below 20 ng/mL.26
Data from GrassrootsHealth ongoing D*Action study actually suggests 80
percent of breast cancer incidences could be prevented simply by
optimizing vitamin D and nothing else! The
key, however, is to achieve the proper blood level, which has nothing
to do with dosage. And the reason this correlation has never been
elucidated before is because no one was using high-enough dosage to
actually get participants vitamin D levels above 60 ng/mL, which is
where you really start seeing these dramatic reductions in disease.
Optimizing Your Vitamin D Is a Key Disease Prevention Strategy
The evidence in support of vitamin D optimization is overwhelming,
and becomes all the more compelling when the blood level is the primary
parameter being measured and tracked. The key take-home message here is
that 2,000 IUs is insufficient for most people, although it may still
cut the risk of cancer by about 25 percent.
Overall, research supports the idea that higher levels offer greater
cancer protection, and even levels as high as 100 ng/mL appear safe and
beneficial. Importantly, having a serum vitamin D level of 60 ng/mL has
been shown to positively impact anyone with breast cancer or Type 1
diabetes, as well as pregnant women and lactating mothers.
It's a shame that so many researchers still have not grasped the
importance of measuring blood levels rather than simply going by dosage,
and relatively low dosages at that. In reality, what this NEJM study
(and others like it) show is that insufficient vitamin D dosage fails to
achieve optimal results. It's not that vitamin D itself is useless.
GrassrootsHealth D*Action study is clearly leading the pack here,
revealing what's required.
It's an ongoing study that relies on public participation, and you can join at any time. To participate, simply purchase the D*Action Measurement Kit
and follow the registration instructions included. (Please note that
100 percent of the proceeds from the kits go to fund the research
project. I do not charge a single dime as a distributor of the test
kits.)
As a participant, you agree to test your vitamin D levels twice a
year during a five-year study, and share your health status to
demonstrate the public health impact of this nutrient. There is a $65
fee every six months for your sponsorship of this research project,
which includes a test kit to be used at home, and electronic reports on
your ongoing progress.
You will get a follow up email every six months reminding you "it's
time for your next test and health survey." By participating in this
project, you help move vitamin D research forward so that, hopefully,
one day we can end this nonsensical debate about whether vitamin D
optimization is worth pursuing or not.
No comments:
Post a Comment