Is Vitamin D to Cancer like Aspirin to MCI?

[marting]

Interesting article in the GlobandMail

http://www.theglobeandmail.com/servlet/story/RTGAM.20070428.wxvitamin28/BNStory/specialScienceandHealth/home

In June, U.S. researchers will announce the first direct link between cancer prevention and the sunshine vitamin. Their results are nothing short of astounding.
A four-year clinical trial involving 1,200 women found those taking the vitamin had about a 60-per-cent reduction in cancer incidence, compared with those who didn't take it, a drop so large — twice the impact on cancer attributed to smoking — it almost looks like a typographical error.

Depending on age, One would expect perhaps (my WAG) 20 to 40 women to have gotten cancer in the time window. A 60 percent drop would be significant. Lets see if this holds up.

An anthropologist has some interesting observations:

http://johnhawks.net/weblog/

[Skeptic Ginger]

Firstly, Linus Pauling was not right regarding his vitamin C studies. Study after study done after Pauling's failed to find the same results. What sparked a half century of vitamin C frenzy that continues to this day is not supportable with scientific evidence. Do the research review.

Vitamin C does not affect your immune system, your ability to recover from a cold and it does not prevent colds. Short of a serious vitamin C deficiency which causes scurvy, there is no benefit of vitamin C in regard to upper respiratory infections whatsoever. If someone has any contradictory evidence about vitamin C, bring it on. I'd like to see it.

That is not to say vitamin C doesn't have other benefits, it might. The studies suggest you need C & E together though, and it may have an effect on living longer. But don't bother taking it for a cold, that isn't evidence supported.

Second, the story says,The new findings that prompted the story haven't yet been published.So my suggestion is take your vitamins but pay no mind to this report until you can see the research report for yourself. Reporters rarely get it right.

[Skeptic Ginger]

If there is little or no evidence for a vitamin benefit, I might still take them if

they are cheap
they do no harm
there might be a benefit, the jury is still out
and there is not a better treatment I am forgoing in place of the vitamins.

Just so folks know you can still take things before all the evidence is in. Megadoses are not wise and megadoses of vitamin c are possibly harmful. The excess is excreted anyway.

[marting]

Firstly, Linus Pauling was not right regarding his vitamin C studies. Study after study done after Pauling's failed to find the same results. What sparked a half century of vitamin C frenzy that continues to this day is not supportable with scientific evidence. Do the research review.


Um, the story is about Vitamin D, not C.
John's headline actually pokes fun at Pauling for missing it by "one letter."

Still, as you say reporters are not known for accuracy nor their ability to judge the quality of a study. It will be interesting to see how this plays out. I think there is a reasonable chance it may be true. With the noted 60% reduction this can be validated easily. If, of course, it is true.

[marting]

What if Zonker Harris was right! Yikes.

[Kaylee]

Great article, thanks for posting this. I'm bumping this for the Mon - Fri crowd a few hours east of the GMT time zone.

It's truly fantastic that there may be a way to reduce the chances of getting cancer so easily and just for pennies a day, at most. It's also great to find out that simply taking more Vitamin D may prevent other health problems.

I will definitely be looking for the official study in June.

[Lisa Simpson]

I'm missing something...where did Vitamin C come into the discussion?

Vitamin D is called the sunshine vitamin because the body synthesizes it from sunshine.

[Kaylee]

Vitamin C was mentioned in the last sentence of the article, but just in a humorous way:

Referring to Linus Pauling, the famous U.S. advocate of vitamin C use as a cure for many illnesses, he said: "Basically, Linus Pauling was right, but he was off by one letter."

[marting]

Another interesting point is that for such a large reduction in cancers over a relatively small window suggests that Vitamin D may be suppressive of extant early stage cancer, not just the initiation. This begs for a larger and detailed study as well as careful review of the study protocols for error, bias, or even fraud. The claims are simply mind boggling.

[Slimething]

I find the news report very troubling on several aspects. First, Vitamin D is a fat soluble vitamin and the proponents of the study have not discussed or even mentioned doing a risk assessment on possible over-accumulation of Vitamin D. Another thing is that no disease etiology is discussed, only a jump to a dubious conclusion that Vitamin D is the operative factor here instead of a pathway assisted by Vitamin D.

Most people get enough Vitamin D in milk and seafood for good health. It's easy to take chances with water-soluble supplements as overexhuberance is washed out of the body but not so with fat-solubles. I really don't like the smell of this article or study.

[Kaylee]

I find the news report very troubling on several aspects. First, Vitamin D is a fat soluble vitamin and the proponents of the study have not discussed or even mentioned doing a risk assessment on possible over-accumulation of Vitamin D.

Thanks for the reminder that Vitamin D is toxic in large doses. :)

However, it seems that:

There is plenty of room between the current recommended amount of 400 IU for most children and adults and the dosages that cause toxicity. While I haven't been able to find a firm number where people agree that toxicity starts, from sources that I have confidence in the bottom limit ranges from 2,500 to 50,000 IU for most adults under 50. Another source that I haven't researched yet suggested 700 IU.
The current recommended amount of 400 IU is too low. For example, a dosage of 800 IU is needed to lower the risks of getting osteoporosis.Links, with cut and pastes, at the bottom .



Another thing is that no disease etiology is discussed, only a jump to a dubious conclusion that Vitamin D is the operative factor here instead of a pathway assisted by Vitamin D.

I agree, the article (like most articles in the mass media) left a lot to be desired. It would have been nice if the article was a couple of sentences longer and explained how a vitamin long linked to only enabling calcium absorption could help in these other areas.

The second link below talks about how research shows that a lack of Vitamin D can lead to a weakened immune system. IIRC some people believe that cancers can be caused by the bodies immune system being weak and failing to recognize and attack viruses that can cause cancer. The other health problems that are listed in the OP's link are also associated with a weakened immune system, IIRC.



Lnks:

From the Harvard School of Public Health
http://www.hsph.harvard.edu/nutritionsource/vitamins.html
The current recommended intake of vitamin D is 5 micrograms up to age 50, 10 micrograms between the ages of 51 and 70, and 15 micrograms after age 70. Optimal intakes are higher, though, with 25 micrograms (1000 IU) recommended for those over age 2. Very few foods naturally contain vitamin D. Good sources include dairy products and breakfast cereals (which are fortified with vitamin D), and fatty fish such as salmon and tuna. For most people, the best way to get the recommended daily intake is by taking a multivitamin, but the level in most multivitamins (10 micrograms) is too low.

and from the same organization:
http://www.hsph.harvard.edu/nutritionsource/ask_the_expert_vitaminD.html (http://www.hsph.harvard.edu/nutritionsource/ask_the_expert_vitaminD.html)

Several randomized trials found that individuals who received 800 IU per day of vitamin D lowered their risk of osteoporosis; trials that provided only 400 IU per day did not show this benefit. It is reasonable to postulate that more than 800 IU per day would provide even more benefit, but this is not proven. Vitamin D intakes greater than 2,000 IU per day have generally not been recommended, and this is probably a conservative upper limit for safety. In fact, recent evidence suggests that doses up to 10,000 IU a day do not cause toxicity - but this does not mean that people should start taking 10,000 IU of vitamin D every day.

There's conflicting information on how much vitamin D can cause an overdose:

From a USA pharmaceutical company:
http://www.merck.com/mmpe/sec01/ch004/ch004l.html (http://www.merck.com/mmpe/sec01/ch004/ch004l.html)
In adults, taking 2500 μg (100,000 IU)/day for several months can produce toxicity.

I thought this article was interesting but I have no idea how valid it is. I don't even know who produced the web site because that information wasn't available at the time of this posting (Home page is being constructed). So FWIW (which may be nothing) the author says most cases of vitamin D toxicity occurs after taking daily dosages of 50,000 IU. However, he also says there may be some problems at daily dosages of as little as 700 IU which clearly contradicts the information available at the Harvard School of Public Health web site and even at Merck's.
http://www.prn2.usm.my/mainsite/bulletin/sun/1996/sun44.html (http://www.prn2.usm.my/mainsite/bulletin/sun/1996/sun44.html)

The prescription of high doses of vitamin D in the absence of a deficiency can result in hypercalcaemia - excessive calcium in blood. If this condition is prolonged, it may lead to heart and kidney damage. Symptoms of vitamin D toxicity include nausea, vomiting, anorexia, headache, weakness, apathy, polyuria and bone pain. As vitamin plays an important role in mineralisation and calcification of bones, the symptoms of excessive ingestion of vitamin D are the result of abnormalities in calcium metabolism. These are largely due to hypercalcaemia which cause calcification of soft tissue and produce renal impairment.

Clinically, most cases of hypervitaminosis D seen in adults are the result of large doses of the vitamin used for the treatment of conditions that are not associated with vitamin D deficiency. Daily ingestion in excess of 2,000IU in children or 75,000IU in adults may produce toxic symptoms related to hypervitaminosis D. For example, most cases of vitamin D toxicity have been reported to occur after the ingestion of greater than 50,000IU daily for several years.

There is wide individual variation in the amount of vitamin D that causes hypervitaminosis. The continued ingestion of 50,000IU or more daily by a person with normal vitamin D sensitivity may result in poisoning. Doses of 60,000IU per day can cause hypercalcaemia, with muscle weakness, Proteinuria, hypertension and irregular heartbeat. Symptoms and signs generally appear two to eight days after acute intoxication with massive doses of vitamin D.

Chronic hypercalcaemia can lead to generalised vascular calcification with high concentration of calcium salts in soft tissues, especially in the kidney. This will exacerbate rapid deterioration of kidney functions. Other sites of calcification may include blood vessels, heart, lungs and skin. The stored vitamin in the body will be released slowly as it has a long plasma half-life of three months. Therefore after discontinuation.

Another potentially toxic action of vitamin D is the effect on fat metabolism. There is some evidence that 700IU to 2,500IU daily in adults may raise the plasma cholesterol level.


….


The writer is a pharmacist at the National Poison Centre, Universiti Sains Malaysia, Penang.



(Bolding mine.)

[Ichneumonwasp]

Very interesting. I would like to know if the cohorts were randomly assigned or if this is going to be like the estrogen-replacement story (those who take vitamin D supplements tend to care for themselves better than those who don't).

For what it's worth, and it be not worth much, there has been a vaguely recognized association between certain types of cancers and the older anti-epileptic drugs, especially phenobarbital and phenytoin. These drugs are enzyme inducers with one of their effects being to reduce vitamin D levels (they seem to increase hepatic degredation of vitamin D). Epileptologists generally try to avoid the older drugs because of this effect and the higher risks of osteoporosis. This might be one more reason to avoid them.

[Kaylee]

I haven't been able to find a firm number where people agree that toxicity starts, from sources that I have confidence in the bottom limit ranges from 2,500 to 50,000 IU for most adults under 50. Another source that I haven't researched yet suggested 700 IU.

Arrrghhh! I was a little sloppy earlier today -- I need to rewrite this. (I'm not use to the various type of measurements used for vitamins -- and I need to replace my laptop's video card or something.).

Revised to:

I haven't been able to find a firm number where people agree that toxicity starts, from sources that I have confidence in the bottom limit starts at about 100,000 IU for most adults under 50. (See link at bottom of post from Merck.) However a link from the Harvard School of Public Education seems to caution against taking as much as 10,000 IU of Vitamin D every day.

Another source that I haven't researched yet suggested toxicity could begin at 700 IU.

[Slimething]

Kaylee, you have done your homework on this issue! Still, I'm not a toxicologist and, until I read a reputable toxicological assessment of the risks vs benefits of Vitamin D, I'll withhold judgement. I agree that a study should not be dismissed due to sloppy reporting but one of the authors gushes about a typical human having a fairly specific habitat to optimize health and I find that extremely speculative and irresponsible. If he cared to look at a map of average life expectancies, he would be very disappointed in what he saw in those regions.

[Kaylee]

.. until I read a reputable toxicological assessment of the risks vs benefits of Vitamin D, I'll withhold judgement.

I think that's very prudent and I'd like to read one of those as well. Hopefully one will come out in June after the formal stuy is released. :)

[Serenity]

Not easy to overdose on Vitamin D... farrrr more likely you're not getting enough. Official safe upper limit for adults is 2000 IU unless you’re on a therapeutic dose. The RDI is really low--200IU. Wouldn’t surprise me if that gets bumped up in the near future.

Potential cancer prevention aside, make sure you get enough; especially, if you reside in extreme latitudes or just aren't exposed to the sun much--crucial if osteoporosis is a concern.

In addition to milk, my favorite source is Cod fish oil--plenty of D and Omega 3. I take in the winter time and then switch to plain ol' fish oil in summer. Get the right one and it won't even taste like fish--more like lemon.

I take it with a quality multivitamin. If you're on a diet all the more important you get on a multi. No need to go crazy with the supplements, but at least take a quality multi.

Many positive studies out pointing to the benefits of Vit D. See the link below for some sensible, generalized advice--excellent website most of you are already familiar with, but perhaps not this section.

http://www.nlm.nih.gov/medlineplus/druginfo/natural/patient-vitamind.html

*Key to grades
A: Strong scientific evidence for this use;
B: Good scientific evidence for this use;
C: Unclear scientific evidence for this use;
D: Fair scientific evidence against this use;
F: Strong scientific evidence against this use.

[Cuddles]

as little as 10 minutes of exposure is thought to be enough to prevent deficiencies
From Serenity's link. So get outside more. If people are suffering from a lack of vitamin D, the answer is not to do anything about their diet and is certainly not to take vitamin supplements. Just go outside. 10 minutes a day should really not be that hard for people to manage. It says an awful lot about society today that people would rather make a fuss about diets and pills rather than actually make a tiny effort to actually get out into the real world for a few minutes.

[Khyron]

I agree completely, Cuddles. I'm going to talk to my boss now about allowing me to take breaks for Vitamin D therapy - 30 minutes at a time, twice daily. Luckily I already own the therapy equipment (a convertible.) :D

[Serenity]

:D

It really is that simple... in summer time at least, for those of us (like myself) in the higher Northern latitudes.

Decent article that does a pretty good job of putting dosage in perspective-
"The good news is that you can't overdose on the vitamin D manufactured by your skin. (http://www.emedicinehealth.com/script/main/art.asp?articlekey=78080)"

[Kaylee]

Right, but its not so simple during other seasons in the Northern latitude, and apparently it's even more of an issue for people of color.

This is all in the article linked in the OP, as well as explanations as to why the recommended amount (400IU for most adults) is too low.

[Serenity]

Kaylee, I enjoyed reading your links. Thanks for taking the time to research it. In one of the sublinks (http://www.hsph.harvard.edu/nutritionsource/ask_the_expert_vitaminD.html) I found the following worth highlighting considering this is an international community.

Milk alone is unlikely to be an adequate source of vitamin D. True, milk is fortified in the U.S. (it is not fortified in most countries). Each glass of fortified milk should contain about 100 IU of vitamin D (but on average, it may contain only 50 IU). So someone would have to drink at least 8 glasses of milk per day to get 800 IU of vitamin D. Moreover, most experts now conclude that 1,000 to 2,000 IU per day of vitamin D may be what we need for optimum health.