Vitamin D 'slashes cancer risk'

Sam, But he is still technically correct, i got this from Wiki:

Until the 1900's, vitamins could only be obtained by eating food. Each food source contains different ratios of vitamins. Therefore if the only source of vitamins is food,
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Sam:Hence for practical purposes, it is considered as a vitamin (required through dietary intake).
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it is really a supplement, but at this point it is a matter of Samantics ...just kidding.:)

I know i hate to be wrong too, but it happens.
 
Correct me if I'm wrong, but isn't there a pre-vitamin state already in our bodies which turn into vitamin D with the exposure to the sun? I don't think the sun magically gives us the vitamin D we need, does it? :D

So we get the pre-vitamin stage from food, and the sun does the rest of the job...

It's like some co-enzime factor or something like that... I can't remember the name anymore... :confused:
 
TruthSeeker said:
Correct me if I'm wrong, but isn't there a pre-vitamin state already in our bodies which turn into vitamin D with the exposure to the sun? I don't think the sun magically gives us the vitamin D we need, does it? :D

So we get the pre-vitamin stage from food, and the sun does the rest of the job...

It's like some co-enzime factor or something like that... I can't remember the name anymore... :confused:
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7-dehydrocholesterol which is converted to previtamin D and then vitamin D.

Cholesterol has its uses too.
 
About vitamin D:

Sources:
1. Diet (mainly fish, fish liver oils, fortified foods like dairy products).
2. Sunlight: UV rays convert 7-dehydrocholesterol in the skin to vitamin D.
3. Supplements.
Diet supplies 3-47% of vitamin D.

Vitamin D is converted to 25-hydroxyvitamin D (25OHD) in the liver.
The enzyme is not regulated and so vitamin D status is reflected by levels of 25OHD.

Hydroxylation of 25OHD to 1,25-dihydroxyvitamin D (1,25-OHD, the active form of vitamin D) occurs in the kidney (and recently has been found to occur in other tissues as well) and is very strongly regulated.

This 1,25-OHD has several functions.

vitamin_D-wirkungen.gif



Vitamin D is the focus of many studies now as low levels have been associated with chronic disease states related to its roles in maintenance of calcium status, bone health, cell growth and differentiation and immune function.

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Further reading: (PDF file)
http://www.ajcn.org/cgi/reprint/79/...1 diabetes, heart disease, and osteoporosis."
 
Thanks you kindly, sam. :)

Do you have any more information on how it prevents diabetes type 1?
 
samcdkey said:
We have endogenous production of cholesterol too!
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Oh yes... But if I remember well from Biology class, plant lipids have a better cholesterol then animal ones... :)
 
TruthSeeker said:
Thanks you kindly, sam. :)

Do you have any more information on how it prevents diabetes type 1?
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Its work in progress.

Currently there is data indicating that 1,25OHD can act to improve glucose uptake by cells. it may do this by decreasing insulin resistance, so that insulin binds to its receptor on the cells and is able to facilitate the translocation of glucose receptors to the plasma membrane of the cell, so that glucose is taken up by the cell.

It has been experimentally shown that treatment with 1,25D can improve glucose tolerance. (Type 2)
http://joe.endocrinology-journals.o...ch="dihydroxyvitamin D and glucose tolerance"

It has also been shown that 1,25D plays a role in the pancreas and may facilitate secretion of insulin. ( Type 1)
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=3516655&dopt=Abstract

It may also protect against the negative effects of inflammation and oxidative damage and protect against auto immune disorders. (Type 1 and 2). The protection conferred by vitamin D may be beneficial against autoimmune destruction of pancreatic beta cells (type 1)
http://joe.endocrinology-journals.o...vitamin D and autoimmune damage and diabetes"
 
TruthSeeker said:
Oh yes... But if I remember well from Biology class, plant lipids have a better cholesterol then animal ones... :)
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To eat yes,

You already produce all the cholesterol you need for

* keeping your cell membranes intact
* boosting mental performance
* aiding digestion
* building strong bones
* building muscle
* maintaining your energy, vitality, libido, and fertility
* regulating your blood sugar
* repairing damaged tissue
* protecting against infectious diseases

http://www.cholesterol-and-health.com/Functions-Of-Cholesterol.html

If, for health reasons you need to reduce your cholesterol, plant sterols have been shown to be beneficial.

However,

Until long-term studies are performed to ensure the absence of adverse effects in all individuals ingesting plant sterol esters, these products should be reserved for adults requiring lowering of total and LDL cholesterol levels because of hypercholesterolemia or the need for secondary prevention after an atherosclerotic event. Although their use as a dietary adjunct in moderate to severely hypercholesterolemic children can be considered, fat-soluble vitamin status should be monitored, and again, long-term studies on safety are required. Whether plant sterols should be used in normocholesterolemic individuals with other risk factors for coronary heart disease (eg, low HDL cholesterol levels) remains to be determined. It has been suggested that introduction of plant sterols into the food supply (eg, by fortification of margarines and food oils) might lower coronary heart disease risk for the whole population.20 However, the excess costs of this measure need to be considered, along with population efficacy and safety data. Thus, although foods containing plant sterols are a promising addition to dietary interventions aimed at improving cardiac risk profiles, more information is required before their routine ingestion is recommended in the general population as a step toward dietary prevention of coronary heart disease.
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http://circ.ahajournals.org/cgi/content/full/103/8/1177
 
TruthSeeker said:
Oh, how lovely.... :m:
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If you are interested in type 1 diabetes, you might be interested in this:

http://diabetes.niddk.nih.gov/dm/pubs/pancreaticislet/

Scientists have made many advances in islet transplantation in recent years. Since reporting their findings in the June 2000 issue of the New England Journal of Medicine, researchers at the University of Alberta in Edmonton, Canada, have continued to use a procedure called the Edmonton protocol to transplant pancreatic islets into people with type 1 diabetes. A multicenter clinical trial of the Edmonton protocol for islet transplantation is currently under way, and results will be announced in several years. According to the Immune Tolerance Network (ITN), as of June 2003, about 50 percent of the patients have remained insulin-free up to 1 year after receiving a transplant. A clinical trial of the Edmonton protocol is also being conducted by the ITN, funded by the National Institutes of Health and the Juvenile Diabetes Research Foundation International.

Researchers use specialized enzymes to remove islets from the pancreas of a deceased donor. Because the islets are fragile, transplantation occurs soon after they are removed.

During the transplant, the surgeon uses ultrasound to guide placement of a small plastic tube (catheter) through the upper abdomen and into the liver. The islets are then injected through the catheter into the liver. The patient will receive a local anesthetic. If a patient cannot tolerate local anesthesia, the surgeon may use general anesthesia and do the transplant through a small incision. Possible risks include bleeding or blood clots.

It takes time for the cells to attach to new blood vessels and begin releasing insulin. The doctor will order many tests to check blood glucose levels after the transplant, and insulin may be needed until control is achieved.
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Deficiency in vitamin D may predispose people to infection


http://www.sciencenews.org/articles/20061111/bob9.asp
In the July 2005 FASEB Journal, Adrian F. Gombart of the University of California, Los Angeles (UCLA) and his colleagues reported that vitamin D boosts production in white blood cells of one of the antimicrobial compounds that defends the body against germs.

On the basis of more than 100 articles that he collected, Cannell and seven other researchers now propose that vitamin D deficiency may underlie a vulnerability to infections by the microbes that cathelicidin targets. These include bacteria, viruses, and fungi, the group notes in a report available online for the December Epidemiology and Infection.

This is only a hypothesis, "but a very credible one" that deserves testing, says immunologist Michael Zasloff of Georgetown University in Washington, D.C.

Behind the hypothesis are recent studies that link vitamin D intake to revved-up cathelicidin production. These investigations point to an infection-fighting role for vitamin D, which is produced in skin exposed to sunlight but is present in few foods.

A study published earlier this year that investigated the relationship between vitamin D and susceptibility to tuberculosis also bolsters the idea proposed by Cannell's team. Scientists have already planned a handful of clinical trials to evaluate the antimicrobial benefits of vitamin D supplementation.

Zasloff argues that if studies support the hypothesis, "we can imagine one day treating infections not by giving somebody a drug, but by giving them safe and simple substances—like a vitamin."
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BTW...does anyone know if humans are the only primates who need vitamin D?

I imagine being covered in fur would inhibit its production in chimps and gorillas.
 
Another question:
Is vitamin D produced from sunlight continously as long as the skin is exposed, or does production shut down when the body has enough?
 
Carcano said:
Another question:
Is vitamin D produced from sunlight continously as long as the skin is exposed, or does production shut down when the body has enough?
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The production of 25 hydroxyvitamin D is unregulated, but it requires the presence of the precursor 7 dehydrocholesterol which is also a precursor for bile acids. So the production of vitamin D would depend on the amount of precursor available. It has been seen in some animal studies that vitamin D is not toxic upto very high levels -50,000 IU and above, when adequate intake is presently set at 400 to 600 IU, a ridicuously low figure in my opinion.

There is insufficient evidence at this time as to what constitutes enough vitamin D.

Present levels are set to avoid disease, like rickets, but we have no knowledge of how much is required for optimal status.
 
samcdkey said:
The production of 25 hydroxyvitamin D is unregulated, but it requires the presence of the precursor 7 dehydrocholesterol which is also a precursor for bile acids. So the production of vitamin D would depend on the amount of precursor available. It has been seen in some animal studies that vitamin D is not toxic upto very high levels -50,000 IU and above, when adequate intake is presently set at 400 to 600 IU, a ridicuously low figure in my opinion.

Present levels are set to avoid disease, like rickets, but we have no knowledge of how much is required for optimal status.
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Ah, and where does dehydrocholesterol come from?

I'm interested in the question of adequate vs. optimal.

If someone spends all day in the sun without clothes (as animals do), how much vitamin D will be produced by exposure.

If its say, 2000 IUs, this is likely the optimal dose, and far above what people are supplmenting themselves with.
 
Carcano said:
Ah, and where does dehydrocholesterol come from?

I'm interested in the question of adequate vs. optimal.

If someone spends all day in the sun without clothes (as animals do), how much vitamin D will be produced by exposure.

If its say, 2000 IUs, this is likely the optimal dose, and far above what people are supplmenting themselves with.
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7 dehydrocholesterol is produced from cholesterol.

Adequate = sufficient to prevent deficiency. For vitamin D this is determined by prevention of the clinical symptoms of rickets. In nutrition this is defined as Adequate Intake (AI).

Optimal = the amount required for optimum health, not merely to prevent deficiency but sufficient to fulfill all functions associated with the nutrient.

To give a rough example, 800 kcals can keep you alive but anything under 1000 kcals sends your body into starvation mode adjusting energy utilisation in favor of critical processes, sacrificing on optimal functioning of the body.

For production you need UVB. Only 5% of UVB makes it through the atmosphere. Also the angle of the sun is important so sufficient intensity is present around midday and mostly in the tropical and temperate regions. Production of melanin (as in dark skin) can interfere with absorption of UVB, as can sunscreen and clothing. Optimal production is generally in the summer months.

In a tropical region at midday, an exposure of 20 mins to direct sunlight can lead to the production of 20000 IU (0.025 mcg) of vitamin D.

Almost everyone is deficient in Vitamin D. Average daily intake is around 50 IU.
 
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