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Vitamin D supplements?
Posted: 02 August 2009 11:28 AM   [ Ignore ]
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Listening to a tech podcast last week one of the hosts mentioned taking Vitamin D supplements. This sounded to me odd, like some sort of vitamin quackery a la Linus Pauling’s obsession with Vitamin C. But now I see it mentioned in the most recent issue of Consumer Reports magazine:

“Many Americans don’t get enough calcium and vitamin D, which together help build bone and might prevent certain cancers and protect the heart ... Citing recent research, our medical consultants say that the current Daily Value for D, 400 IUs, is too low; most people should aim for 800 to 1,000 IUs.” (Sept. 09 issue, p. 9. It’s in the report on Calcium + Vitamin D orange juice).

Well, Consumer Reports isn’t always right. I double checked at the UC Berkeley’s Wellness Guide online, HERE. Their bottom line: “In any case, consider taking 800 to 1,000 IU of supplemental vitamin D a day (multivitamins usually supply only 400 IU).”

And the Harvard HEALTHbeat is even more strict. See HERE:

“Depending on how much a person started out with, a daily intake of about 2,000 IU—the upper limit set by the National Academy of Sciences—is necessary before blood levels get high enough for vitamin D to have its full disease-fighting effects. ... A daily 1,000-IU supplement should take care of your minimum needs. If your multivitamin contains some vitamin D, but less than 1,000 IU, you can take a separate vitamin D supplement to make up the difference.”

(See also the article in Sept. 08 Harvard Women’s Health Watch HERE).

I must say, I hadn’t been aware of this. My inclination is to say that if three respected sources like these give virtually identical information, I’m inclined to accept it. Anyone hear otherwise?

[ Edited: 02 August 2009 11:30 AM by dougsmith ]
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Posted: 02 August 2009 12:43 PM   [ Ignore ]   [ # 1 ]
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How reliable are those Nutritional labels on food? It says on my milk-jug, 1 serving gives 25% Daily allowance of Vitamin D. Is that accurate, ya think?
Maybe I’ll start taking a Flintstone Vitamin a day again.

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Posted: 02 August 2009 01:02 PM   [ Ignore ]   [ # 2 ]
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I don’t recall the sources, but I’ve seen this in a couple of scientific publications along with such things as the seasonal variation in some illnesses in temperate climates correlated with the the amount of sunlight people are exposed to, and observations that more highly pigmented people in cooler climates are particularly affected by lack of vitamin D. 

Vyazma, that 25% is based on the 400 I.U.  level.  And I’m not sure, but quite possibly the milk is fortified with a vitamin D precursor that still requires skin exposure to ultraviolet radiation (sunlight) to convert to the vitamin.  Probably wouldn’t hurt to go to your nearest Costco and by a big bottle of their store-brand multivitamins and take one or two a day.  At two a day you won’t be exceeding any of the government recommended upper limits (except vitamin D which is almost certain to be raised very soon).

Occam

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Posted: 02 August 2009 01:07 PM   [ Ignore ]   [ # 3 ]
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I generally shy away now from multivitamins, and certainly from anything that has more than 100% of the US RDA, because I know that some vitamins can actually be harmful in large doses. That’s why even if one should take a vitamin D supplement daily, I wouldn’t suggest doing so by doubling up on multivitamins, or the like.

And yes, Vyazma, 25% would be 100 IU, or roughly 10% of what Harvard was suggesting.

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Posted: 02 August 2009 01:13 PM   [ Ignore ]   [ # 4 ]
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The main two vitamins that seem to cause problems are A and pyridoxine, and it would require taking five or more multivitamins a day to exceed the safe levels. 

Occam

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Posted: 02 August 2009 01:27 PM   [ Ignore ]   [ # 5 ]
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Occam - 02 August 2009 01:13 PM

The main two vitamins that seem to cause problems are A and pyridoxine, and it would require taking five or more multivitamins a day to exceed the safe levels. 

The Harvard article HERE claims that there is an adverse reaction between vitamins A and D:

“Unless you live in the South and spend a fair amount of time outdoors, some kind of supplement is the answer. Most multivitamins contain 400 IU of vitamin D. But you shouldn’t just take two, because the vitamin A in the pill may interfere with the vitamin D.”

They suggest taking a 1,000-IU pill per day.

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Posted: 02 August 2009 03:51 PM   [ Ignore ]   [ # 6 ]
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I used to take a Flintstone’s chewable. It was convenient. Plus it seemed less like I was taking any pills-which I don’t take.
I guess I’ll re-up on some Flintstones. For me, getting close to an RDA with a multi is good enough. I eat alot of fruits and vegetables.
Plus 2 or 3 servings of milk a day.
Anybody else here have any weird side-effects of taking a Vitamin to close to bedtime? I did, and it wasn’t pleasant. It took me awhile to figure out it was the vitamin.

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Posted: 02 August 2009 03:57 PM   [ Ignore ]   [ # 7 ]
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Occam - 02 August 2009 01:02 PM

I don’t recall the sources, but I’ve seen this in a couple of scientific publications along with such things as the seasonal variation in some illnesses in temperate climates correlated with the the amount of sunlight people are exposed to, and observations that more highly pigmented people in cooler climates are particularly affected by lack of vitamin D. 

Vyazma, that 25% is based on the 400 I.U.  level.  And I’m not sure, but quite possibly the milk is fortified with a vitamin D precursor that still requires skin exposure to ultraviolet radiation (sunlight) to convert to the vitamin.  Probably wouldn’t hurt to go to your nearest Costco and by a big bottle of their store-brand multivitamins and take one or two a day.  At two a day you won’t be exceeding any of the government recommended upper limits (except vitamin D which is almost certain to be raised very soon).

Occam

Interesting bits Doug and Occam! Occam, it would hurt me to get to my nearest Costco. I don’t think there are any in NY State. LOL
Maybe downstate.

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Posted: 02 August 2009 04:32 PM   [ Ignore ]   [ # 8 ]
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Quoting Doug/quoting the Harvard Health Letter: 

But you shouldn’t just take two, because the vitamin A in the pill may interfere with the vitamin D.“

  I’ve tried searching on the Internet and haven’t been able to find any other reference to this besides that one sentence.  I’d certainly like to know what the mechanisms and effects are, but I don’t feel comfortable accepting any pronouncement, even from something like the Harvard Health Letter, without seeing some specific data. 

Vyazma, I suggested Costco because they are cheap and reliable, however, you could try Walmart (ugh) or Sam’s Club (ugh), or even a local drug store chain.

Occam

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Posted: 02 August 2009 04:39 PM   [ Ignore ]   [ # 9 ]
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Vyazma, I suggested Costco because they are cheap and reliable, however, you could try Walmart (ugh) or Sam’s Club (ugh), or even a local drug store chain.

Occam

What is a Costco? A grocery store, or a drug store? Or is it like a wal-mart?
Aren’t there any foods one could eat to get Vita-D naturally?

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Posted: 02 August 2009 04:45 PM   [ Ignore ]   [ # 10 ]
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Yes, it’s a nationwide chain of large volume, discount stores.  However, it’s the opposite of Walmart in that it encourages an employee union, gives them a wide range of benefits and contributes to liberal causes and candidates.

Sure, you could eat large amounts of cold water fish like salmon and cod, and you could get as much sunlight on your bare skin as you can, living in northern N.Y.
If you want to stick with natural stuff, you could buy codliver oil, either in capsules or straight, and take that. 

Occam

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Posted: 02 August 2009 06:08 PM   [ Ignore ]   [ # 11 ]
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Occam - 02 August 2009 04:32 PM

I’ve tried searching on the Internet and haven’t been able to find any other reference to this besides that one sentence.  I’d certainly like to know what the mechanisms and effects are, but I don’t feel comfortable accepting any pronouncement, even from something like the Harvard Health Letter, without seeing some specific data. 

Understood, and certainly I agree. That said, I’d think the Harvard folks are pretty credible. If anyone on this thread knows any more, please chip in.

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Posted: 03 August 2009 09:06 AM   [ Ignore ]   [ # 12 ]
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Thanks for the links Doug. If I can add my 2 cents worth here. This subject somewhat related to the other thread regarding resveritrol. There is certainly a wealth of data supporting the body’s need for vitamin D. That information is decades old. Vitamin D deficiency can clearly lead to Rickets in children and Osteomalacia in adults, but this requires severe vitamin D deficiency. The studies you are referring to above concerns new work on what I would call a “relative deficiency” in vitamin D. There does seem to be mounting evidence that even in people who get amounts of vitamin D which we once thought were adequate there may be increased incidences of various diseases. While this is certainly interesting it is by no means conclusive. Most of the studies I have seen are retrospective studies not randomized doubled blinded studies. As we all know, there are significant problems with such studies and I don’t believe these issues have been properly sorted out yet.

In order to decide whether it makes sense to issue a public advisory to increase the intake of vitamin D we need to answer two questions. Is there sufficient data to suggest that there are benefits to this course of action, and do the benefits outweigh the risks? It does seem that there may be multiple benefits to increasing ones vitamin D intake but again we need randomized DB studies to confirm this and it seems like we are jumping the gun a bit here. We also have no safety studies to prove that increasing Vit D intake isn’t going to be harmful in some way. For anyone who is doubtful about my concerns take a look at the studies done on Vit A when they tried to reduce the risk of lug cancer in smokers - it had the reverse effect.

Two other things to answer some comments above:

The vitamin D found in milk is Vitamin D3 and does not require exposure to sunlight to become active. There are about 100iu of Vit D in an 8oz glass of milk which is 1/4 of the current recommended RDA

Getting more sunlight is NOT the best way to increase your Vit D levels. Getting vitamin D this way is not healthier and the UV exposure is the best way to increase your chances of getting skin cancer. Skin cancer is the most common of cancer in adults and increasing each year.

[ Edited: 03 August 2009 09:08 AM by macgyver ]
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Posted: 03 August 2009 09:18 AM   [ Ignore ]   [ # 13 ]
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Thanks for the commentary, macgyver. Yes, a lot of your analysis was what went through my mind when I was reading this material. To a layperson, the fact that three prestigious health-related organizations (Consumer Reports also has a Health Letter) are willing to come out publicly for an increase in the vitamin D RDA, and indeed a suggestion that people take supplements, puts this into a different class from prior vitamin alerts in the media.

Are you then suggesting that the CR, Harvard and UC Berkeley health letters are all jumping the gun?

The first question is whether there is any possibility for harm in an otherwise healthy adult taking a daily 1,000 IU capsule of vitamin D. As far as I’m aware, there is not.

The second question is whether there is a significant preponderance of the evidence in favor of upping the RDA. This is where we no doubt get in to issues of study quality, etc. I have to assume the people who are behind these publications are competent to make that decision; I’d like to see some strong evidence otherwise, or from equally respected organizations arguing the contrary.

The third question is whether we are able to get this higher level of the vitamin from a normal diet, etc. Once again, it seems from the evidence presented that we are not.

Agreed about sunlight. For the reasons you mention, I avoid sunlight, and this is one of the many factors that leads me to take this sort of advice with particular seriousness. Since I am unlikely to get vitamin D from the sun anyhow, I should take particular care to get it from other sources.

I will only say that this info has led me to start taking vitamin D, however I am very open to counterevidence in the future.

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Posted: 03 August 2009 09:29 AM   [ Ignore ]   [ # 14 ]
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macgyver - 03 August 2009 09:06 AM

Skin cancer is the most common of cancer in adults and increasing each year.

I remember watching an episode on TED on how different skin colours adapt to varied UV exposures. I found it interesting when the person presenting the talk, Nina Jablonski, said that as bad as skin cancer is for white people, the vitamin D deficiency for dark people is much worse. Which makes me think: the 1,000-IU pill per day is a recommended dose for whom? For people with white skin?

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Posted: 03 August 2009 09:32 AM   [ Ignore ]   [ # 15 ]
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I personally believe that they are all jumping the gun. While they are all published by reputable outfits, I think that the pressure to provide leading edge medical advice leads many lay publications to make recommendations before the evidence is all in because they dont want to be “late to the ball”. I personally dont think the evidence is sufficient.

You ask an important question? Is it harmful for an adult to take 1000iu of Vit D every day? If you’re asking about acute dramatic harmful effects the answer is no. This is sort of like asking about the beneficial effects. There is no doubt that Vit D can prevents significant and severe illnesses like rickets and osteomalacia, but when you’re talking about illnesses that may only occur inn a small portion of the population ( as is the case when your talking about an increase in cancer or heart attack death rates for example) then it takes large long term prospective studies to work that out just like it will take those sorts of studies to determine if the current beneficial claims are in fact real. When you’re advising people to do something that may only have a marginal benefit you’re obligated to prove that it does not also have a marginal risk.

I tend to be a bit conservative about new treatments though. I don’t speak for the medical profession and there no doubt may be many who disagree with me, but at least I’ve given you the rationale for my position. I hate when publications simply say “its the opinion of most experts” and don’t give you anything to support that opinion as though there expertise is enough to carry the weight of the argument.

[ Edited: 03 August 2009 09:35 AM by macgyver ]
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