Multivitamin dosage question? Can it be bad?
October 26, 2013 11:10 AM   Subscribe

Ok, this won't be long. Anyway, I'm not too crazy on the supplements department, usually just taking multivitamin along my normal diet, and fish oil. I decided to buy a higher quality one, and got a "Highly Dosed Max Vit-Min" recommended by the lady at the supplement store, because I excercise on a fairly regular basis recently. I'm not too scared anything can happen, but I'm confused by the amounts on the label and recommended daily value (RDV in the US, I guess?) percentages. For example, Thiamine (Vitamin B1) is 80mg, 7273% RDV. Riboflavine is also 80mg, 5714% RDV. Isn't that overkill to take daily (seriously seven thousand percent above the RDV )? Can I get hypervitaminosis from this stuff, or does the fact that I excercise somehow modify my requirements? For reference on the low end, Calcium for example is 8mg, 1% RDV. Or am I just being silly and not understanding labels??
posted by ahtlast93 to Health & Fitness (15 answers total) 1 user marked this as a favorite
You're being sold on pseudo-science. There appears to be more and more evidence that multi-vitamins are not good for you and in fact may be correlated with health problems later on.

Those values are pretty out there, likely you will just pee out the excess, but that, they say, is just money down the drain.

You are reading the label correctly (though see if they are meaning the % after taking multiple pills during the day VS a single pill)

I'd speak to a Doctor or Nutritionist as opposed the person at the vitamin store who has a conflict of interest in unselling you on more expensive supplements or has bought into the "woo" surrounding supplements

The common consensus for people with normal/healthy diets seems to be that the RDA is pretty good, but if it is low, it's low by a few percentage points or maybe 100%, but not to the tune of 1000% off.
posted by bottlebrushtree at 11:38 AM on October 26, 2013 [2 favorites]

B (and C) vitamins are water-soluble, which basically means that you pee out whatever your body doesn't use. (In contrast, vitamins A, D, E and K get stored in body fat and you can more easily overdose on them. Minerals like calcium and iron get processed differently and are more likely to be harmful if you take way too much.)

The RDA values are debatable and not some sort of magic standard. B and C vitamins are frequently sold in doses far above the RDA because larger doses don't seem to cause any clear harm and might be useful. (Some studies that have shown issues with taking vitamin supplements, but generally it hasn't been any sort of immediate issue, and I think it's still not totally clear.)
posted by needs more cowbell at 11:43 AM on October 26, 2013 [1 favorite]

Find a pharmacist in your area who specializes in natural remedies and vitamins. They are out there (real pharmacists, I mean). He or she will prescribe an appropriate dosage of EACH supplement to fit your lifestyle and that way you will not have to worry about toxicity or wasting your money.
posted by brownrd at 11:43 AM on October 26, 2013

If you're concerned with hypervitaminosis, you basically only have to worry about fat-soluble vitamins: A, D, E, & K. You'll just pee excess amounts of the other vitamins out. If you eat a reasonable diet (it doesn't even have to be a great diet), you'll get plenty of vitamins. Vitamin pills are generally a waste of money, IMO.
posted by Benny Andajetz at 11:43 AM on October 26, 2013 [1 favorite]

Or, what needs more cowbell said.
posted by Benny Andajetz at 11:44 AM on October 26, 2013

The recommended daily value for vitamins and minerals are completely useless to be taken as a guide for how much to take. They were established many, many, many years ago and they were determined in all cases as the amounts needed to avert a "deficiency" disease, for example rickets. They were set at a time when we had little knowledge about vitamins and merely thought of them as substances that we need to avert a deficiency state (and health as a whole was thought in this way, as avoiding disease, rather than a positive state in itself). The RDAs are always very, very conservative. Any intelligent "medical professional" (or person) now understands these substances in a more complex manner. For example, there may be great benefits to the complexities of the body to taking vitamin C beyond not getting rickets. The B vitamins in particular may often be listed on vitamin labels greatly exceeding the RDA (as on yours) because the B vitamins are water soluble and are for the most part non toxic (you pee any excess out and need to replenish constantly, it doesn't just accumulate in the body to toxic levels), vitamin C is also water soluble. Minerals on the other hand do stay in the body and there are specific amounts you should take. Same with fat soluble vitamins (they get stored in the fat cells of the body) like vitamin E and A. But even with fat soluble vitamins the guide to appropriate dose should not be the RDA. If you want to read up yourself, the best source would be one of Andrew Weil's books. He's profoundly intelligent on anything health related. But most likely your supplement is perfectly safe.
posted by Blitz at 11:49 AM on October 26, 2013 [5 favorites]

There is not really any broad consensus on the use of multivitamins, at all. This is coming out already in this thread - comments saying 'vitamins are unnecessary' and comments saying 'see a vitamin pharmacist'.

On the one hand you have a sort of 'intuitive' view that, hey, if I need X amount of this stuff to live, I'd better take a vitamin containing X amount! There are also 'anecdotal' reports from people - including some famous scientists - that taking huge doses of vitamin this or vitamin that makes them more resilient to illness, etc.

On the other hand, the RDV is largely based on what you should get from a healthy diet naturally, and there's not a lot of evidence that 'more is better'. Studies have fairly consistently shown that, for otherwise healthy people without a deficiency, there isn't any benefit to taking a multivitamin. Specific vitamin studies have largely been inconclusive - a few have shown greater risk from taking a vitamin than from not taking it.

The only exception I can think of is Vitamin D which seems to be preventative against depression and - rather than being something that we evolved to get from food and still get from food - could conceivably work to compensate for the fact that we don't spend as much time in the sun as our ancestors did.

If you're worried about a deficiency there are blood tests your doctor can prescribe to assess your actual levels of many nutrients/vitamins.

But without a blood test showing an actual deficiency, with the study results overall so uncertain, and the lack of controlled studies for many of the vitamins that are being pushed at the 'cutting edge' of supplement stores, I would be extremely skeptical of anyone (like a "vitamin pharmacist") saying they can predict exactly what doses of X and Y and Z supplements you 'need'. We haven't even answered the question of whether supplementation at all is a good idea.
posted by Lady Li at 11:57 AM on October 26, 2013 [1 favorite]

The gist of what Harvard says (and my doctor is in agreement) is that you can take a multivitamin, but there is no point in taking one with more than the recommended RDA for most vitamins as long as you eat a healthy diet. Except, it does not hurt anything to have extra vitamin D, and that may actually be a good idea.

So, others have answered your question about the mega levels in the vitamins you currently have, but once you use them up, don't bother getting more vitamins with those mega levels, it is not worth the expense.

Men's Health made a list in Oct. 2012 (in slideshow format for some reason) of some recommended multivitamins, that seems pretty decent.
posted by gudrun at 11:59 AM on October 26, 2013 [2 favorites]

Response by poster: arr well, seems like in general multivitamins are kind frowned upon. I never researched it myself this much until now, I just took it for granted to occasionally take one as a student, because my diet was very far from ideal. But yup, seems sort of pseudo-sciencey really.

Ah well, I'll finish these and no more afterwards
posted by ahtlast93 at 12:05 PM on October 26, 2013 [2 favorites]

Another vote for "pseudoscience." There is increasing evidence that multivitamins are not only useless, but bad for you, and recent evidence that fish oil, specifically, may raise the risk of some cancers significantly.

The entire nutritional supplement industry is fundamentally unregulated and corrupt. Nothing you read on any label should be assumed to be accurate or truthful or regulated. The science is unequivocal: unless you're pregnant, malnourished, or have certain specific chronic conditions, diseases, or hereditary issues, all of which would require a doctor to determine and to specify the appropriate nutritional supplementation, you are at best wasting money with almost all nutritional supplements, and very likely taking serious health risks with at least some of them.

Step away from the GNC or wherever you are getting the bogus information in your question. They are in the business of lying to you to make a buck.
posted by spitbull at 12:28 PM on October 26, 2013 [3 favorites]

I don't chime in on health threads much anymore, and I won't comment on the specific question of the poster, but AskMe constantly says "You don't need a multivitamin, as long as you eat a healthy diet.". AskMe is bad at this question.

Guess what? Most people don't have any idea what a healthy diet is. You, the person reading this comment, don't either. Most people who eat a "healthy diet" are chronically deficient in something, be it D or potassium, calcium or etc.

People spend their lives eating calorie dense food that has no nutritional value and running subclinical vitamin deficiencies and end up metabolic syndrome at 50, and they say, "...but I eat a healthy diet." and when the actual details of their perceived healthy diet are examined, they had a salad for lunch three days each week and had an orange for at breakfast for two days each week. Everything else they ate was the low nutrient, calorie dense food.

gudrun's link to the what Harvard says is the correct answer to the question of should a person take a multivitamin. The correct answer is that they are so cheap, and eliminate a lot of the risk of nutritional deficiencies, that unless you have been specifically advised by your medical professional not to take one, there is no reason to not take a good quality multivitamin each day.
posted by 517 at 1:47 PM on October 26, 2013 [10 favorites]

Guess what? Most people don't have any idea what a healthy diet is.

The problem is, that multiple studies have failed to show that multivitamins address problems arising from inadequate diets, as the body processes vitamins in food very different to vitamins in pills (betacarotene is the classic example). Indeed, the example of metabolic syndrome syndrome is an excellent - multivitamins will absolutely do nothing to address this.

The other problem is homeostasis, i.e. people use taking a multivitamin as an excuse to indulge in poorer health choices that have far more impact of the long run. A pill won't address cholesterol issues, diabetes issues, obesity, etc etc. And several vitamins have been linked to bad health outcomes, like vitamin e and increased rates of prostate cancer in men, for example.

"After reviewing the literature of the prevalence of dietary supplement use, it seemed to show that use of dietary supplements is increasing, but it does not appear to be correlated with improved public health," says Chiou who conducted the study along with Chao-Chin Yang of National Kaohsiung University of Hospitality and Tourism and Chin-Sheng Wan of Southern Taiwan University... To put it simply, people who take dietary supplements may have the misconception that they are invulnerable to health problems and may make poor decisions when it comes to their health – such as choosing fast food over a healthy and organic meal."
posted by smoke at 2:44 PM on October 26, 2013 [1 favorite]

I agree very much with what you, 517, say here. The point about a "healthy diet" is highly relevant, along with the just as often cited and completely ununderstood idea of "moderation". The vast majority of people have little understanding of what a "healthy diet" is, even though they reference it all the time. It's taken as something simple, given, that every one already understands and it is nothing of the sort. Nor do people seem to understand that the spectrum between an unhealthy and healthy diet is vast. The possibilities of what we eat, how much we eat of given foods, over a regular range of time opens this up for incredible variation. So what on earth do people think they are talking about when they say you don't need a multi if you eat a "healthy diet". My guess is they have no idea. And this seemingly simple statement is an over-simplification.

On the other hand, I disagree that a healthy diet is something that can never be known, that is too elusive, by anybody. I think you somewhat agree since despite your claim that you don't "know" what a healthy diet is, you seem to have ideas (reference to salads and oranges). It can never be determined in the way that people here would seem to want, that's for sure. It's not a question that science can answer definitively. Science can look at aspects of certain nutrients and even certain foods, and these in relation to specific diseases, but it can never definitively answer what can only be understood holistically. Scientific studies can at best "point" to what might make up a healthy diet, but at the end of the day the question of diet and the question of health is a holistic one and can only be understood as such. Further, the fact that science can only look at nutrition in relation to specific disease states, and that "health" is, as I alluded to in my post above, more than a lack of disease, these studies are already limited in what in can say about something as complex and "holistic" as health.

I doubt very much that a multi can make a great difference to one's health, in fact, I'm sure of it. However, had I not been taking a multi for over ten years I would have become even more deficient in Vitamin D than I was when I was tested recently, as well as ferritin. I'm grateful that I had been taking a multi all those years since I'm sure than being low in Vitamin D and ferritin was having negative consequences for me (I mean the reason I was tested was because I was displaying ill health).
posted by Blitz at 3:49 PM on October 26, 2013

Best answer: smoke: I don't mean to be impolite, but the amount of education I have to do on the topic to get you up to speed to understand my argument is just excessive, and I am unwilling to do it on a Saturday night because I basically have to write an introductory textbook to explain my argument.

When you're citing what is probably a short duration, small sample study from a psychological journal and the concept of homeostasis as evidence against what I am saying (I can't read the actual study and the abstract doesn't tell me about sample size or duration, unfortunately) I know we're not speaking with a shared knowledge base, and to be fair, most of the people reading this comment don't have that shared knowledge base either.

I really would like to explain it in a way that gets through, but it's just not practical for me to do, so I am left with making an appeal to authority, which I also can't do because I am not willing to identify myself on this page.

So here's what I'll say:

Here's a recent, large, long-duration, double-blind, placebo controlled study that concludes, "...daily multivitamin supplementation modestly but significantly reduced the risk of total cancer."

If you actually go in a read that abstract, you'll see the evidence is a little weak but, when they cost a few cents each day, why would a person not take one? Why does AskMe always come to the same the ridiculous conclusion that people shouldn't take multivitamins?
posted by 517 at 3:52 PM on October 26, 2013 [2 favorites]

Mod note: Remember, please: don't debate other answerers, just stick to the question. Thanks.
posted by restless_nomad (staff) at 4:41 PM on October 26, 2013

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