Vitamin D Seminar

[Guest guest]

Hi folks:

I may have mentioned a while ago that I was scheduled to attend a seminar on

vitamin D featuring some of the world's leading authorities on the topic. I did

in fact attend, and put together a write-up of some of what was said.

Curiously, while sending this to people I know who might be interested, I forgot

that I hadn't posted it here. DUH! So, to fix that omission, here it is. It

is a bit long, but so was the seminar!

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I went to a full day seminar on vitamin D recently at the University of Toronto.

Some of the featured speakers were leaders in the field so it was interesting to

hear their current thoughts on this topic. The following are some of the things

I learned, although much of this has been fairly widely known for some time.

Approximately 150 people attended, a rather small number, which seems to

indicate that vitamin D is still not considered a health issue of major

importance in the 'mainstream'.

[Please note that I do not doubt I will have made errors in what I write here.

I am to blame for errors, not the speaker! I may also have forgotten, or not

understood the significance of, much else that I heard.]

The first item of interest was a plot of data for about 100 individuals. It

showed oral vitamin D intake on the X axis and their serum levels of 25(OH)D on

the Y axis. It demonstrated that there is a huge range of blood levels for a

given level of intake. The message seems to be that, since it is the blood

level that is important, whatever one's intake, it is essential to get one's

blood level tested to know whether one is appropriately 'replete' with the

vitamin. FWIW, in my case, given my current intake, my serum 25(OH)D was right

in the middle of the range of the chart. It is easy to understand that those

who are out in the sun extensively would appear above the median level as

measured by their oral intake. But it is especially interesting to see that

some people supplementing sizeable amounts of the vitamin have a blood level

below - sometimes substantially so - the median level for people with a similar

intake.

Dr. Reinhold Vieth noted that about 25% of the vitamin ingested ends up as

25(OH)D in the blood stream. Its 'half life' is estimated at two months. All

ethnic groups, he said, have vitamin D problems except those of european

ancestry, whose fair skin can sometimes permit the manufacture of adequate

amounts from sunlight. The median level of members of the african Masai tribe,

he said, is 104 nmol/L. Dr. Vieth also defined the term 'nutrient' as a food

component a deficiency of which will cause disease. This was a nice

introduction to Dr. Heaney's presentation.

Dr. Heaney defined it the same way, and added that if you get enough of it you

do not get the disease. However he noted that what I would term 'the

conventional wisdom' in medicine still to a large extent believes that a

deficiency of one nutrient will cause only one disease. For example, it is

widely thought that a deficiency of vitamin C will result only in scurvy. And

another vitamin, only beri-beri. Dr. Heaney challenged this.

He believes the one deficiency/one disease orthodoxy is false. In addition he

noted that there are deficiency diseases which have 'short latency' periods

which everyone is familiar with - such as a three month delay between

deprivation of vitamin C and the appearance of overt symptoms of scurvy. It is

comparatively easy for an observer to connect the dots of causation in a case

like this. But he emphasized that there are also deficiency diseases that

exhibit long latency. And it is very difficult for investigators to recognize

the connection between a disease that appears at age 60 the cause of which may

have been a lifetime deficiency of a single nutrient, or perhaps a combination

of nutrients. This, Dr. Heaney believes, is the case for vitamin D.

He explained that he believes the reason a large proportion of the general

public is still ignorant of the need to maintain sufficient vitamin D nutrition

is because of a bias among the news media to report only negative information.

" Cholesterol is bad " so the news media are keen to publicize this. But

information that " vitamin D is good " is largely ignored.

One very recent important discovery he mentioned was that rather than the active

version of vitamin D - 1,25(OH)2,D3 - being produced only in the kidneys, it is

now known that every cell has the ability to produce it if adequate 25(OH)D is

available. This may be the critically important information which explains the

apparent benefit of vitamin D in helping prevent cancer. Ten percent of the

human genome, he said, depends for its proper functioning on an adequate level

of vitamin D. It appears that the mechanism by which 25(OH)D prevents cancer

may be that " it unlocks the DNA library within each cell " . The DNA in each cell

has the ability, if appropriately fed, to find the solution to diseases in that

cell. He appeared to say that if a cell is turning cancerous the " DNA library " ,

if unlocked by 1,25(OH)2,D3, can almost always fix the problem.

He mentioned a study by Liu et al (2006) in Science, which showed benefits of

vitamin D for innate immunity. He observed that this supports the remarkable

fact that, when rickets was common in the United States, the cause of death of

children with rickets was infection!

He noted that as much as 85% of the population of Massachusetts is deficient

25(OH)D. He also said that if everyone supplemented 2600 IU daily 2.5% of the

Massachusetts population would still be deficient. An increased intake of 200

IU daily will normally raise serum levels by 2 ng/ml (which is 5 nmol/L).

Seasonal variation in serum levels is about 10nmol/L, he said.

Another interesting graphic showed serum levels of 25(OH)D on the X axis and a

variety of diseases, including many cancers, plotted on the Y axis according to

the serum levels needed for prevention according to recent studies. In addition

to rickets the diseases included in this chart were: all cancers, breast cancer,

ovarian cancer, colon cancer, non-hodgkins lymphoma, kidney cancer, endometrial

cancer, type 1 diabetes, fractures, falls, multiple sclerosis and heart attacks

in men. What was striking about this chart was that while the amount of D

required to prevent rickets was small, a much greater amount was required to

protect against all the other diseases listed. Of course the current official

RDA for vitamin D is based solely on the amount necessary to prevent rickets.

Another chart showed data from Hypponen, Lancet, November 2001, which found a

78% reduction in type 1 diabetes with adequate vitamin D nutrition.

The next speaker was oncologist Dr. O'Connor, talking on the use of

vitamin D in treating breast cancer. Her patients, she said, are always

deficient serum 25(OH)D. Recurrance rates are reduced when vitamin D is

supplemented. The blood level reflects the previous three months exposure to

the vitamin. Supplementation with an incremental 1000 IU daily results in an

increase in the serum level of 10 ng/ml (25 nmol/L).

Next, Dr. Cedric Garland made a presentation by phone line from California. He

noted that new scientific discoveries are said to go through three stages of

acceptance. First, they are ridiculed. Second, they are violently opposed.

Later they become accepted as self evident. He made mention of the well known

fact that around the world where UVB light is absent cancer incidence is higher

- notably colon cancer and breast cancer. That the part of the electro-magnetic

spectrum effective for the creation of vitamin D in the skin is 295-315 nm.

That four UVB photons and one molecule of cholesterol will create one molecule

of vitamin D. That studies show serum levels of 23 ng/ml will reduce colon

cancer incidence by 50%. That in women serum levels of 52 ng/ml will reduce

breast cancer incidence by 48%. One study of breast cancer found an 85%

reduction in risk at 62 ng/ml. Survival after twelve years was 42% better at

levels greater than 30 ng/ml. A randomized controlled trial in post-menopausal

females, after four years of followup, found a 7% cancer incidence in those

taking placebo compared with just 1.5% in an experimental group supplemented

with modest-to-moderate amounts of calcium and vitamin D. Dana Farber Cancer

Center found colon cancer patients with serum levels of 40 ng/ml experienced 50%

less mortality. In Dr. Garland's view 125-275 nmol/L is a reasonable range of

serum 25(OH)D to aim for. He commented that for the study which found increased

incidence of kidney stones with increased vitamin D intake, the most likely

explanation was dehydration. Somewhere between 3000 and 5000 IU of vitamin D

daily will be metabolized if it is available.

Dr. Whiting noted that blood levels of vitamin D in response to sun exposure

will vary with many factors including age, adiposity, skin pigmentation and

pregnancy, in addition to season, etc.. One minimal erythymal dose (MED) for a

naked person is 20,000 IU. For a white person with a skin type which 'mostly

burns', on 21st June, at latitude 42.5 degrees north, with 25% of skin exposed,

getting one quarter of a MED in six minutes will generate 1000 IUs of vitamin D

(Webb, Engelsen, 2006).

Dr. White, from McGill, defined innate immunity as the immune function which

responds to attack but has no memory. He has found anti-microbial immune

response to be " strongly dependent " on circulating 25(OH)D concentration. In

addition, he said it LOOKS LIKE there may also be anti-viral effects, but that

it is 'early days' to start making claims about this.

Dr. Vieth made a second presentation, this time on safety of the vitamin. It

has a two month half-life. The amount in the standard international unit is a

tiny amount when measured in grams, and perhaps it should be prescribed in

micrograms instead of IUs. The key sign expected with vitamin D toxicity would

be hypercalcemia. In one study individuals taking 1000 mcg a day - 49,000 IUs -

showed no change in urinary or serum calcium. (Of course he is not recommending

anyone supplement anywhere remotely close to that amount.) 40,000 IU per day is

likely to be the very lowest intake that might be associated with hypercalcemia.

One group which had accidentally overdosed with vitamin D had serum levels of

1555 nmol per litre! Their only symptom was gastroenteritis. When asked why

'the authorities' were reluctant to move more quickly on raising the RDA for

vitamin D it was said that it was 'safer' from their point of view. They would

not want to raise the RDA and then, possibly, a little later, have to admit they

had been mistaken and reduce it again. Also mentioned was one study which had

found a U-shaped relationship between vitamin D and prostate cancer.

In a queston period it was stated that it is UVA which causes melanoma, and UVB

which prevents it. Also, that for individuals over age 60 four times as as much

sun exposure would be required to generate the same amount of vitamin D as

someone in their twenties. Also, it was stated that, contrary to popular

opinion, vitamin D is NOT a hormone. Some of its metabolites are, but not the

vitamin itself. When asked, Dr. Vieth declined to disclose how much vitamin D

he supplements.

NOTE: It was said that transcripts of the presentations will be available on

the website of grassrootshealth.com

Rodney.