important Vitamin D information

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Vitamin D in a New Light

by W. , Jr., MD

by W. , Jr., MD

There are

thirteen vitamins humans need for growth and development and to maintain good

health. The human body cannot make these essential bio-molecules. They must be

supplied in the diet or by bacteria in the intestine, except for vitamin D.

Skin makes vitamin D when exposed to ultraviolet B (UVB) radiation from the

sun. A light-skinned person will synthesize 20,000 IU(international units) of

vitamin D in 20 minutes sunbathing on a Caribbean

beach.

Vitamin D

is also unique in another way. It is the only vitamin that is a hormone, a type

of steroid hormone known as a secosteroid,

with three carbon rings.

Steroid

hormones such as cortisone, estrogen, and testosterone have four carbon rings.

Ultraviolet B radiation in sunlight breaks open one of the rings in a steroid

alcohol present in the skin, 7-dehydrocholesterol,

to form vitamin D (cholecalciferol). The liver changes this molecule into its

circulating form, 25-hydroxyvitamin D

(calcidiol, 25[OH]D), the " vitamin D " blood tests measure. Cells

throughout the body absorb 25-hydroxyvitamin D and change it into 1,25-dihydroxyvitamin D (calcitriol), the

active form of vitamin D that attaches directly to receptors on the DNA of

genes in the cell¡¯s nucleus.

The

vitamin D hormone system controls the expression of more than 200 genes and the

proteins they produce. In addition to its well-known role in calcium

metabolism, vitamin D activates genes that control cell growth and programmed

cell death (apoptosis), express mediators that regulate the immune system, and

release neurotransmitters (e.g., serotonin) that influence one¡¯s mental

state.

Severe

deficiencies of some vitamins cause vitamin-specific diseases, such as beriberi

(from a lack of vitamin B1, thiamine), pellagra (B3, niacin), pernicious anemia

(B12), and scurvy, (vitamin C). A deficiency in iodine produces a goiter,

mental retardation, and, when severe, cretinism.

Rickets,

a softening and bending of bones in children, first described in 1651, is

another nutritionally-specific disease. It reached epidemic proportions

following the industrial revolution, which began in the 1750s. In the 19th

century, before the importance of exposing children to sunlight was recognized,

the majority of children that lived in cities with sunless, narrow alleyways

and pollution developed rickets. An autopsy study done in Boston in the late 1800s showed that more

than 80 percent of children had rickets.

Early

in the 20th century an investigator found that cod liver oil could

prevent rickets in puppies. The nutritional factor in the oil that promotes

skeletal calcium deposition was named " vitamin D, " alphabetically

after already-named vitamins A, B, and C. Rickets was thought to be another

vitamin-deficiency disease, and the curative agent, a steroid hormone, was

mislabeled a " vitamin. "

Now, a

century later, a wealth of evidence suggests that rickets, its most florid

manifestation, is the tip of a vitamin D insufficiency/deficiency iceberg. A

lack of Vitamin D can also trigger infections (influenza and tuberculosis),

autoimmune diseases (multiple sclerosis, Type 1 diabetes, rheumatoid arthritis,

and inflammatory bowel disease), cardiovascular disease, and cancer. Practitioners

of conventional medicine (i.e., most MDs) are just beginning to appreciate the

true impact of vitamin D deficiency. In 1990, medical journals published less

than 20 reviews and editorials on vitamin D. Last year they published more than

300 reviews and editorials on this vitamin/hormone. This year, on July 19, 2007, even the New

England Journal of Medicine, the bellwether of

pharmaceutically-oriented conventional medicine in the U.S., published a review on vitamin

D that addresses its role in autoimmune diseases, infections, cardiovascular

disease, and cancer (N Engl J Med 2007;357:266¨C281).

Up until

1980, doctors thought that vitamin D was only involved in calcium, phosphorus,

and bone metabolism. Then two investigators proposed http://ije.oxfordjournals.org/cgi/reprint/9/3/227?ijkey=c289c939fed91ac8b4bde3d42c741c35b7459059

that vitamin D and sunlight could reduce the risk of colon cancer. A

growing body of evidence indicates that they were right and that vitamin D can

prevent a whole host of cancers ¨C colon, breast, lung, pancreatic,

ovarian, and prostate cancer among them. Colon

cancer rates are 4 to 6 times higher in North America and Europe,

where solar radiation is less intense, particularly during the winter months,

compared to the incidence of colon cancer near the equator. People with low

blood levels of vitamin D and those who live at higher latitudes are at

increased risk for acquiring various kinds of cancer. Many epidemiological, cohort, and case control studies prove, at least

on a more likely than not basis, that vitamin D supplements and adequate

exposure to sunlight play an important role in cancer prevention (Am J Public Health 2006;96:252¨C261).

There is now strong scientific evidence that vitamin D does

indeed reduce the risk of cancer. Evidence from a well-conducted,

randomized, placebo-controlled, double-blind trial proves beyond a reasonable

doubt that this is the case, at least with regard to breast cancer. A Creighton

University study has shown that women over the age of 55 who took a 1,100 IU/day

vitamin D supplement, with calcium, and were followed for 4 years had a highly

statistically significant (P <0.005)

75% reduction in breast cancer (diagnosed after the first 12 months) compared

with women who took a placebo (Am J Clin

Nutr 2007;85:1568¨C1591).

Some of

the genes vitamin D activates make proteins that halt cancer by inducing

apoptosis (programmed cell death), which destroys aberrant cells before they

become cancerous, like adenoma cells in the colon and rectum. http://www.ncbi.nlm.nih.gov/sites/entrez?itool=abstractplus & db=pubmed & cmd=Retrieve & dopt=abstractplus & list_uids=6576856

Others

promote cell differentiation and reining in of out-of-control growth of cancer

cells (like prostate cancer cells). http://www.ncbi.nlm.nih.gov/sites/entrez?db=pubmed & cmd=Retrieve & dopt=AbstractPlus & list_uids=16158255 & query_hl=1 & itool=pubmed_docsum

Vitamin

D-expressed genes inhibit angiogenesis, the formation of new blood vessels that

malignant tumors need to grow, as studies on lung http://www.ncbi.nlm.nih.gov/sites/entrez?db=pubmed & cmd=Retrieve & dopt=AbstractPlus & list_uids=15718253 & query_hl=23 & itool=pubmed_DocSum

and breast cancers http://www.ncbi.nlm.nih.gov/sites/entrez?db=pubmed & cmd=Retrieve & dopt=AbstractPlus & list_uids=10969786 & query_hl=30 & itool=pubmed_docsum

show.

Other

genes inhibit metastases, preventing cancer that arises in one organ from

spreading its cells to other parts of the body, as studied in breast, http://www.ncbi.nlm.nih.gov/sites/entrez?db=pubmed & cmd=Retrieve & dopt=AbstractPlus & list_uids=10969786 & query_hl=30 & itool=pubmed_docsum

and prostate cancers. http://www.ncbi.nlm.nih.gov/sites/entrez?db=pubmed & cmd=Retrieve & dopt=AbstractPlus & list_uids=10090302 & query_hl=27 & itool=pubmed_docsum

Vitamin D

also expresses genes that curb cardiovascular disease. One gene controls the

renin-angiotensin system, which when overactive causes hypertension (high blood

pressure). Others stifle the immune system-mediated inflammatory response that

propagates atherosclerosis and congestive heart failure (Curr Opin Lipidol 2007;18:41¨C46).

Multiple

sclerosis (MS) is a neurologically devastating disease that afflicts people

with low vitamin D levels. Its victims include the cellist Du Pr¨¦,

whose first symptom was loss of sensation in her fingers, and some 500,000

Americans who currently suffer from this malady. MS is an autoimmune disease,

where the body¡¯s immune system attacks and destroys its own cells. With

multiple sclerosis, T cells in the adaptive immune system, Th1 cells (CD4 T

helper type 1 cells), attack the myelin sheath (insulation) of the axons (nerve

fibers) that neurons (brain cells) use to transmit electrical signals. The

Vitamin D hormone system regulates and tones down the potentially

self-destructive actions of Th1 cells. These cells make their own

1,25-dihydroxyvitamin D if there is a sufficient amount of vitamin D

(25-hydroxyvitamin D) circulating in the blood. Researchers have shown that the

risk of MS decreases as the level of vitamin D in the blood increases (JAMA 2006;296:2832¨C2838). People

living at higher latitudes have an increased risk of MS and other autoimmune

diseases. Studies show that people who live below latitude 35¡ã (e.g., Atlanta)

until the age of 10 reduce the risk of MS by 50% (Toxicology 2002;181¨C182:71¨C78 and Eur J Clin Nutr 2004;58:1095¨C1109).

In a

study published earlier this year, researchers evaluated 79 pairs of identical

twins where only one twin in each pair had MS, despite having the same genetic

susceptibility. They found that the MS-free twin had spent more time outdoors

in the sun ¨C during hot days, sun tanning, and at the beach. The authors

conclude that sunshine is protective against MS (Neurology 2007;69:381¨C388). http://news.bbc.co.uk/1/hi/health/6906712.stm

New

research suggests that influenza is also a disease triggered by vitamin D deficiency.

Influenza virus exists in the population year-round, but influenza epidemics

are seasonal and occur only in the winter (in northern latitudes), when vitamin

D blood levels are at their nadir. Vitamin D-expressed genes instruct

macrophages, the front-line defenders in the innate immune system, to make

antimicrobial peptides, which are like antibiotics (Science 2006;311:1770¨C1773). These peptides attack and

destroy influenza virus particles, and in human carriers keep it at bay.

(Neutrophils and natural killer cells in the innate immune system and

epithelial cells lining the respiratory tract also synthesize these virucidal

peptides.) Other vitamin D-expressed genes rein in macrophages fighting an

infection to keep them from overreacting and releasing too many inflammatory

agents (cytokines) that can damage infected tissue. In the 1918 Spanish flu

pandemic, which killed 50 million people, of which 500,000 were Americans,

young healthy adults (as happened to my 22-year-old grandmother) would wake up in

the morning feeling well, start drowning in their own inflammation as the day

wore on, and be dead by midnight. Autopsies showed complete destruction of the

epithelial cells lining the respiratory tract due, as researchers now know, to

a macrophage-induced overly severe inflammatory reaction to the virus. These

flu victims were attacked and killed by their own immune system, something

researchers have found vitamin D can prevent (Epidemiol

Infect 2006;134:1129¨C1140).

Randomized clinical trials need to be done to test the

vitamin D theory of influenza. With what we know now, however, perhaps an

annual shot of 600,000 IU of vitamin D (Med

J Aust 2005;183:10¨C12) would be more effective in preventing

influenza than a jab of flu vaccine.

Our

species evolved in equatorial Africa where the

sun, shining directly overhead, supplies its inhabitants with year-round

ultraviolet B photons for making vitamin D. Our African ancestors absorbed much

higher doses of vitamin D living exposed in that environment compared to the

amount most humans obtain today. A single mutation that occurred around 50,000

years ago is responsible for the appearance of white skin in humans. It turns

out that a difference in one rung, or base pair, in the 3 billion-rung DNA

ladder that constitutes the human genome determines the color of one¡¯s

skin (Science 2005;310:1782¨C1786).

White skin, with less melanin, synthesizes vitamin D in sunlight six times

faster than dark skin. People possessing this mutation were able to migrate to

higher latitudes, populate Europe, Asia, and North America,

and be able to make enough vitamin D to survive.

The

majority of the world¡¯s population now lives above latitude 35¡ã N and is

unable to synthesize vitamin D from sunlight for a period of time in winter

owing to the angle of the sun. At a large solar zenith angle, ozone in the

upper atmosphere will completely block UVB radiation. In Seattle

(47¡ã N) and London

(52¡ã N), from October to April UVB photons are blocked by the atmosphere so

one¡¯s skin cannot make vitamin D. (The half-life of circulating vitamin D

is approximately one month.) Making matters worse, even when UVB radiation is

available in sunlight, health authorities, led by the American Academy

of Dermatology, warn people to shield themselves from the sun to avoid getting

skin cancer.

Except

for oily fish like (wild-only) salmon, mackerel, and sardines and cod liver oil

¨C and also sun-dried mushrooms ¨C very little vitamin D is naturally

present in our food. Milk, orange juice, butter, and breakfast cereal are fortified

with vitamin D, but with only 100 IU per serving. One

would have to drink 200 8-oz. glasses of milk to obtain as much vitamin D as

skin makes fully exposed to the noonday sun.

The U.S.

Food and Nutrition Board in the Institute of Medicine puts the Recommended

Dietary Allowance (RDA) for vitamin D at 200 IU for children and adults less

than 50 years old, 400 IU for adults age 50¨C70, and 800 IU for adults

over the age of 70. Most multivitamin preparations contain 400 IU of vitamin D.

These guidelines are directed towards maintaining bone health and are

sufficient to prevent rickets ¨C but not cancer, cardiovascular disease,

multiple sclerosis, or influenza. Without

evidence to support it, the board arbitrarily set the safe upper limit for

vitamin D consumption at 2,000 IU/day.

Vitamin D

(25-hydroxyvitamin D) blood levels, the barometer for vitamin D status, are

measured in nanograms per milliliter (ng/ml) or nanomoles per liter (nmol/l),

where ng/ml = 0.4 nmol/l. Children and adults need a vitamin D blood level >8 ng/ml to prevent rickets and

osteomalacia (demineralization and softening of bones) respectively. It takes a

concentration >20 ng/ml to

keep parathyroid hormone levels in a normal range. A level >34 ng/ml is required to ensure peak

intestinal calcium absorption. Finally, neuromuscular performance steadily

improves in elderly people as vitamin D levels rise up to 50 ng/ml. Accordingly, a vitamin D blood

level <8 ng/ml is regarded as severely

deficient; 8¨C19, deficient;

and 20¨C29, insufficient, i.e.,

too low for good health. A level >30 ng/ml is sufficient, but experts now

consider 50¨C99 ng/ml to be the optimal

level of vitamin D. Levels 100¨C150 ng/ml are excessive and >150 ng/ml, potentially toxic.

A majority of Americans have insufficient or deficient

vitamin D blood levels. In veterans undergoing heart surgery at the Seattle VA

hospital, I found that 78% had a low vitamin D level: 12% were insufficient;

56%, deficient; and 10% were severely deficient.

In order to enjoy optimal health, we should maintain a

vitamin D blood level of ¡Ý50¨C99 ng/ml. Without sun exposure, to

reach a level of 50 ng/ml requires taking a 5,000 IU/day vitamin D3 supplement.

There are two kinds of vitamin D supplements: vitamin D3 (cholecalciferol), the

kind our skin makes, and vitamin D2 (ergocalciferol), a synthetic variant made

by irradiating plants. Vitamin D2 is only 10¨C30% as effective in raising

25-hydroxyvitamin D blood levels compared to vitamin D3, leading the authors of

a recent study conclude, " Vitamin D2 should not be regarded as a nutrient

suitable for supplementation or fortification " (Am J Clin Nutr 2006;84:694¨C697).

Concerns

about vitamin D toxicity are overblown, along with those about sun exposure. As

one researcher in the field puts it, " Worrying about vitamin D toxicity is

like worrying about drowning when you¡¯re dying of thirst. " The LD50

of vitamin D in dogs (the dose that will kill half the animals) is 3,520,000

IU/kilogram. One can take a 10,000 IU vitamin D supplement every day, month after

month safely, with no evidence of adverse effect. (Am J Clin Nutr 1999;69:842¨C856). A person must consume

50,000 IU a day for several months before hypercalcemia (an elevated calcium

level in the blood, which is the initial manifestation of vitamin D toxicity)

might occur. Vitamin D in a physiologic dose

(5,000 IU/day) prevents the build up of calcium in blood vessels. (Circulation 1997;96:1755¨C1760). If

one takes 10,000 IU of vitamin D a day and spends a lot of time in the sun, it

would be prudent to check vitamin D blood level to ensure that it does not

exceed 100 ng/ml.

Sensible

sun exposure should be encouraged, not maligned. If

one avoids sunburn, the sun¡¯s health-giving benefits far outweigh its

detrimental effects. A large body of evidence indicates that sunlight

does not cause the most lethal form of skin cancer, malignant melanoma. A U.S.

Navy study found that melanoma occurred more frequently in sailors who worked

indoors all the time. Those who worked outdoors had the lowest incidence of

melanoma. Also, most melanomas appear on parts of the body that are seldom

exposed to sunlight (Arch Environ Health 1990;45:261¨C267).

Sun exposure is associated with increased

survival from melanoma (J Natl Cancer Inst 2005;97:195¨C199).

Another study showed that people who had longer lifetime exposure to the sun

without burning were less likely to get melanomas than those with less exposure

(J Invest Dermatol

2003;120:1087¨C1093.)

The rise in skin cancers over the last 25 years parallels

the rise in use of sunscreen lotions, which block vitamin D-producing UVB

radiation but not cancer-causing ultraviolet A radiation (UVA). (Newer

sunscreen lotions also block out UVA.) Each year there are 8,000 deaths from

melanoma and 1,500 deaths from nonmelanoma (squamous and basal cell) skin cancer.

Surgical excision of nonmelanoma skin cancers cures them, except in rare cases

where the growth has been allowed to linger for a long time and metastasize.

Dr. Cannell, Executive Director of the Vitamin D Council, makes this

point: 1,500 deaths occur each year from non-melanoma skin cancer, but

1,500 deaths occur each day from

other cancers that vitamin D in optimal doses might well prevent. (The Vitamin

D Council website

http://www.vitamindcouncil.com/

is an excellent source of information on vitamin D.)

The U.S.

government and its citizens currently spend $2,000 billion dollars ($2

trillion) on " health care, " i.e., sickness care, each year. The cost

of taking a 5,000 IU supplement of vitamin D every day for a year is $22.00.

The cost for 300 million Americans taking this supplement would be $6.6 billion

dollars. The number and variety of diseases that vitamin D at this dose could prevent,

starting with a 50 percent reduction in cancer, is mind-boggling. If everyone

took 5,000 IU/day of vitamin D, the U.S. " health care "

industry would shrink. It would no longer account for 16 percent of the gross

domestic product.

Health

food stores typically do not sell vitamin D3 in 5,000 IU tablets, but they are

readily available online. BIO-TECH

Pharmacal produces both 5,000 and 50,000 IU tablets of Vitamin D3, which

online sites sell. Some people prefer to take one 50,000 IU table a week

(equivalent to 7,100 IU a day) and a three-day course of 150,000 IU vitamin D

at the first sign of a cold.

Two sites

that sell both " D3- 5 (5,000 IU) and " D3-5 (50,000

IU) are http://www.lifespannutrition.com/

$15.70 US for 250 capsules of 5000 IU $30 for 100 of the 50,000 IU capsules

http://www.vitalady.com/cgi-bin/commerce.cgi?preadd=action & key=1068

$15.99 US

for 250 capsules of 5000 IU $24.99 for 100 of the 50,000 IU capsules

September 10, 2007

email him at dmillerjr@... is a

cardiac surgeon and Professor of Surgery at the University

of Washington in Seattle. He is a member of Doctors for Disaster Preparedness http://www.ddponline.org / and writes articles on a variety of subjects for

LewRockwell.com. His web site is www.donaldmiller.com

Copyright

© 2007 LewRockwell.com

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