# multi-vitamin pills and dosage **URL:** \ **Category:** Factual Questions\ **Created:** [May 21, 2004, 8:03pm UTC](https://boards.straightdope.com/t/multi-vitamin-pills-and-dosage/246421 "2004-05-21T20:03:41Z")\ **Posts on this page:** 16\ **Page:** 1
**Author:** ![duffer](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/duffer/32/1026_2.png) [@duffer](https://boards.straightdope.com/u/duffer)\ **Post date:** [May 21, 2004, 8:03pm UTC](https://boards.straightdope.com/t/multi-vitamin-pills-and-dosage/246421/1 "2004-05-21T20:03:41Z")
I’ve wondered this for so long, I’m going to start a thread. For years I’ve taken a vitamin every day. But I’ve always had a question. Looking at the list of vitamins and minerals, it gives a percentage of the RDA for adults. I can live with that, but I need answers to feel better about it. According to the label, an adult should take one pill a day. That’s it, one pill for adults. My question is this. Do you need more of any vitamin or mineral if you’re over the average? For example, my sister is 5’7" and weighs 120 pounds. I’m 6’4" and weigh 230 pounds. Can that one pill really offer the same requirement of, say, magnesium? (Or any other nutrient?) It seems since I have more body mass, I may have more cells that require these nutrients, thereby needing more in quantity. Anyone know how this works? I know it takes more alcohol to get me buzzed, so I automatically assume the biotin in the pills will offer a lesser concentration in me than her. Should I take more, or should she take less? If it doesn’t matter, please tell me why. I’m starting to think it’s a scam. ---
**Author:** ![alice\_in\_wonderland](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/alice_in_wonderland/32/176_2.png) [@alice\_in\_wonderland](https://boards.straightdope.com/u/alice_in_wonderland)\ **Post date:** [May 21, 2004, 8:11pm UTC](https://boards.straightdope.com/t/multi-vitamin-pills-and-dosage/246421/2 "2004-05-21T20:11:17Z")
I believe that you are correct - I know for sure that people need different amounts of certain things depending on what’s going on in their life. For instance, teens, pregnant women and breast feeding women need more folate, women in general need more calcium, etc. etc. However, most pill manufacturers now have different pills depending on who you are, with differing levels of some things - Centrum now has Centrum silver for adults over 50, Centrum F for women, Centrum M for men, Centrum P for purple people, etc. etc. so it seems like they’ve addressed your concerns in that way. If you are taking the cheapest, lowest, bottom of the barrel vitamin you can get your hands on, you may not be getting much out of it anyway. ---
**Author:** ![tremorviolet](https://avatars.discourse-cdn.com/v4/letter/t/e47774/32.png) [@tremorviolet](https://boards.straightdope.com/u/tremorviolet)\ **Post date:** [May 21, 2004, 8:20pm UTC](https://boards.straightdope.com/t/multi-vitamin-pills-and-dosage/246421/3 "2004-05-21T20:20:24Z")
In theory, the RDA should be adequate. They were rounded up slightly to cover most adults: > [@](#): > > The RDA’s are based on scientific research of both humans and animals and are set at levels to provide for 98% of all healthy persons living in the US. There is a cushion built in so that if you get 67% of the RDA for a nutrient, you should be getting a minimum amount as an average person. [source page](http://www.dietitian.com/rda.html) The problem with RDA’s is they were only calculated to prevent _deficiencies_, not to be the optimum amount. So there is a lot of debate over whether or not they’re accurate. For instance, some scientists believe the RDA for Vitamin C is inadequate for overall health. The government has been developing [DRIs](http://www.nal.usda.gov/fnic/etext/000105.html) (Daily Reference Intakes) to replace the RDAs but I don’t know if they’re ever planning on applying them to food labels. These are still provided independent of body size in the interests of simplifying things for the consumer. ---
**Author:** ![Chairman\_Pow](https://avatars.discourse-cdn.com/v4/letter/c/838e76/32.png) [@Chairman\_Pow](https://boards.straightdope.com/u/Chairman_Pow)\ **Post date:** [May 21, 2004, 9:20pm UTC](https://boards.straightdope.com/t/multi-vitamin-pills-and-dosage/246421/4 "2004-05-21T21:20:07Z")
Most of the literature I’ve read (crazy alternative health stuff and COSMO) has made the point that the vitamins shouldn’t be used as a substitute for obtaining the vitamins thoughout your normal diet, but should instead be used to “top off” items that you’re not getting the amount that your body needs. There are [services](http://www.dragondoor.com/t01.html?l=743283) that will test your hair/blood, etc. for vitamin/mineral/etc. levels and recommend a specific program that will work for you, if that’s a concern. The idea behind that testing is solid, but I couldn’t vouch for its effectiveness or necessity. The same guy who offers that test maintains that vitamins are actually bad for you by only absorbing the stuff that you already have an excess of. Don’t follow his logic, but I submit it for your consideration as well. ---
**Author:** ![barbitu8](https://avatars.discourse-cdn.com/v4/letter/b/839c29/32.png) [@barbitu8](https://boards.straightdope.com/u/barbitu8)\ **Post date:** [May 21, 2004, 10:09pm UTC](https://boards.straightdope.com/t/multi-vitamin-pills-and-dosage/246421/5 "2004-05-21T22:09:46Z")
> [@Chairman Pow](#): > > There are [services](http://www.dragondoor.com/t01.html?l=743283) that will test your hair/blood, etc. for vitamin/mineral/etc. levels and recommend a specific program that will work for you, if that’s a concern. The idea behind that testing is solid, but I couldn’t vouch for its effectiveness or necessity. Do you have any cites showing that the testing is valid? I read somewhere a long time ago that this is bogus. **tremorviolet** > [@](#): > > For instance, some scientists believe the RDA for Vitamin C is inadequate for overall health. An issue of the _Wellness Letter_ a couple of years ago stated that raising the RDA is being considered. That issue showed studies indicating that 250-500 mg daily (instead of the now RDA of 60) is optimal. A one-a-day vitamin tablet is insurance, and does not obviate your eating a healthy diet. So if the amounts therein is not enough for you, your regular diet should more than enough compensate for that. The only exception is vitamin C, and I take about 500 mg in powder form every morning in my OJ, the OJ containing not only some C but bioflavonoids as well. ---
**Author:** ![Chairman\_Pow](https://avatars.discourse-cdn.com/v4/letter/c/838e76/32.png) [@Chairman\_Pow](https://boards.straightdope.com/u/Chairman_Pow)\ **Post date:** [May 23, 2004, 6:33pm UTC](https://boards.straightdope.com/t/multi-vitamin-pills-and-dosage/246421/6 "2004-05-23T18:33:03Z")
> [@barbitu8](#): > > Do you have any cites showing that the testing is valid? I read somewhere a long time ago that this is bogus. No, but like I said, the theory is correct. What exactly is bogus about it? Medical professionals take blood sampels to determine mineral deficencies all the time (roommate had it done) and the other part of his theory: different people require not only different nutritional “doses” (for lack of a better term), but also absorb their nutrition differently. The only thing that I could find to argue with about his book (wihtout having read it mind you) is that maybe his testing facility is subpar, or he just sends everyone a form letter talking that’s made to look like a customized report. Like I said, the theory is sound. ---
**Author:** ![tremorviolet](https://avatars.discourse-cdn.com/v4/letter/t/e47774/32.png) [@tremorviolet](https://boards.straightdope.com/u/tremorviolet)\ **Post date:** [May 23, 2004, 6:48pm UTC](https://boards.straightdope.com/t/multi-vitamin-pills-and-dosage/246421/7 "2004-05-23T18:48:53Z")
> [@Chairman Pow](#): > > No, but like I said, the theory is correct. What exactly is bogus about it? Medical professionals take blood sampels to determine mineral deficencies all the time (roommate had it done) and the other part of his theory: different people require not only different nutritional “doses” (for lack of a better term), but also absorb their nutrition differently. The only thing that I could find to argue with about his book (wihtout having read it mind you) is that maybe his testing facility is subpar, or he just sends everyone a form letter talking that’s made to look like a customized report. Like I said, the theory is sound. Nah, it’s a scam. Here’s a[Quackwatch article](http://www.quackwatch.org/01QuackeryRelatedTopics/hair.html). ---
**Author:** ![Cillasi](https://avatars.discourse-cdn.com/v4/letter/c/71e660/32.png) [@Cillasi](https://boards.straightdope.com/u/Cillasi)\ **Post date:** [May 23, 2004, 6:55pm UTC](https://boards.straightdope.com/t/multi-vitamin-pills-and-dosage/246421/8 "2004-05-23T18:55:29Z")
Most have already said it - vitamin and mineral tablets are meant to be a supplement. Unless your doctor recommends, you should not increase the recommended dosage of any vitamins or minerals for various reasons. 1. Although the body flushes out many excess vitamins and minerals, there are those that accumulate in your tissues. Accumulation of these non-expelled substances can cause numerous health problems. 2. Certain substances, especially in abundance, can interfere with other medications you may be taking; increasing or decreasing their efficacy which can be extremely detrimental to your health. 3. Certain substances, taken in abundance, may exacerbate existing medical conditions. 4. Certain factors (i.e., other medications, medical conditions) may interfere with the normal metabolism of certain vitamins and minerals. To be trite, remember that more is not necessarily better, and that just because it’s billed as “all natural” does not mean it’s safe. ---
**Author:** ![Chairman\_Pow](https://avatars.discourse-cdn.com/v4/letter/c/838e76/32.png) [@Chairman\_Pow](https://boards.straightdope.com/u/Chairman_Pow)\ **Post date:** [May 23, 2004, 8:36pm UTC](https://boards.straightdope.com/t/multi-vitamin-pills-and-dosage/246421/9 "2004-05-23T20:36:00Z")
> [@tremorviolet](#): > > Nah, it’s a scam. Here’s a[Quackwatch article](http://www.quackwatch.org/01QuackeryRelatedTopics/hair.html). Fair enough. ---
**Author:** ![barbitu8](https://avatars.discourse-cdn.com/v4/letter/b/839c29/32.png) [@barbitu8](https://boards.straightdope.com/u/barbitu8)\ **Post date:** [May 23, 2004, 10:29pm UTC](https://boards.straightdope.com/t/multi-vitamin-pills-and-dosage/246421/10 "2004-05-23T22:29:47Z")
> [@Cillasi](#): > > 1. Although the body flushes out many excess vitamins and minerals, there are those that accumulate in your tissues. Accumulation of these non-expelled substances can cause numerous health problems. And “those” vitamins are the fat-soluble ones, A, D, and K, but K is not a problem. Medical literature is replete with people who OD’d on A or D or both, thinking that more is better. Thanks, \*\* tremorviolet \*\*. Saved me the work of finding it. ---
**Author:** ![antechinus](https://avatars.discourse-cdn.com/v4/letter/a/fbc32d/32.png) [@antechinus](https://boards.straightdope.com/u/antechinus)\ **Post date:** [May 24, 2004, 3:53am UTC](https://boards.straightdope.com/t/multi-vitamin-pills-and-dosage/246421/11 "2004-05-24T03:53:01Z")
In a normal healthy diet you will be getting all the vitamins and minerals you need. Any supplemental vitamins are either excreted or metabolised and excreted. Accounting for body mass is therfore not a problem as far as meeting your recomended allowance. Bodymass _is_ however an important consideration in avoiding overdosing (points listed by **Cillasi** ). Many overdoses are by children. ---
**Author:** ![barbitu8](https://avatars.discourse-cdn.com/v4/letter/b/839c29/32.png) [@barbitu8](https://boards.straightdope.com/u/barbitu8)\ **Post date:** [May 24, 2004, 8:28pm UTC](https://boards.straightdope.com/t/multi-vitamin-pills-and-dosage/246421/12 "2004-05-24T20:28:04Z")
> [@antechinus](#): > > In a normal healthy diet you will be getting all the vitamins and minerals you need. Any supplemental vitamins are either excreted or metabolised and excreted. > > Accounting for body mass is therfore not a problem as far as meeting your recomended allowance. Bodymass _is_ however an important consideration in avoiding overdosing (points listed by **Cillasi** ). Many overdoses are by children. Excess fat-soluble vitamins are not either excreted or metabolised and excreted, but stored in the body, leading to serious side-effects, which, fortunately, for the most part are reversible. Most of the overdosing of A & D have been by adults. ---
**Author:** ![antechinus](https://avatars.discourse-cdn.com/v4/letter/a/fbc32d/32.png) [@antechinus](https://boards.straightdope.com/u/antechinus)\ **Post date:** [May 24, 2004, 11:50pm UTC](https://boards.straightdope.com/t/multi-vitamin-pills-and-dosage/246421/13 "2004-05-24T23:50:12Z")
> [@barbitu8](#): > > Excess fat-soluble vitamins are not either excreted or metabolised and excreted, but stored in the body, leading to serious side-effects, which, fortunately, for the most part are reversible. Most of the overdosing of A & D have been by adults. Eh? Vitamin A & D are persistants, are they? Do they they accumulate? So how are the side effects reversible. Stop taking the vitamin and the symptoms dissappear. Why? [http://news.bbc.co.uk/2/hi/south\_asia/3079438.stm](http://news.bbc.co.uk/2/hi/south_asia/3079438.stm) > [@](#): > > The high court in India’s north-eastern state of Assam has held both the United Nations children’s organisation and the state government responsible for the death of more than 30 children. > The children died after they were administered vitamin A supplements in November 2001. [http://abclocal.go.com/ktrk/health/022304\_health\_vitamins.html](http://abclocal.go.com/ktrk/health/022304_health_vitamins.html) > [@](#): > > While all consumers are at risk of vitamin and mineral overdose, some groups are of particular concern. > > “Children, because of their smaller size, can get into trouble with lower amounts than adults,” explains Dr. Daniel E. Rusyniak, medical toxicologist with Indiana University School of Medicine in Indianapolis, Ind. I have read other cases of children becoming very sick as a result of parents administering too high a dose of fat soluble vitamins. ---
**Author:** ![barbitu8](https://avatars.discourse-cdn.com/v4/letter/b/839c29/32.png) [@barbitu8](https://boards.straightdope.com/u/barbitu8)\ **Post date:** [May 25, 2004, 1:29am UTC](https://boards.straightdope.com/t/multi-vitamin-pills-and-dosage/246421/14 "2004-05-25T01:29:18Z")
[http://www.cc.nih.gov/ccc/supplements/vita.html#risk](http://www.cc.nih.gov/ccc/supplements/vita.html#risk) > [@](#): > > Hypervitaminosis A refers to high storage levels of vitamin A in the body that can lead to toxic symptoms. There are three major adverse effects of hypervitaminosis A: > > birth defects, > liver abnormalities, > reduced bone mineral density that may result in osteoporosis [http://www.cc.nih.gov/ccc/supplements/vitd.pdf](http://www.cc.nih.gov/ccc/supplements/vitd.pdf) [http://my.webmd.com/content/article/83/97624.htm?lastselectedguid={5FE84E90-BC77-4056-A91C-9531713CA348}](http://my.webmd.com/content/article/83/97624.htm?lastselectedguid=%7B5FE84E90-BC77-4056-A91C-9531713CA348%7D) > [@](#): > > There are four families of fat-soluble vitamins: vitamin A, vitamin D, vitamin E, and vitamin K. These vitamins need to be dissolved in fat before they can be absorbed in the intestine. Low-fat and low-calorie diets, whether by chance or by purpose, risk not providing enough of these vitamins. > > Dietary fats and the fat-soluble vitamins are absorbed into the lymph vessels, bypassing the portal blood system that takes water-soluble nutrients to the liver. After a long climb up to your shoulder, they are dumped into the left subclavian artery. > > Vitamins A and D can be toxic in large amounts when taken over a long period. They are stored in fatty tissues and the liver, and they can accumulate over time. Unlike vitamin C and the B complex, the fat-soluble vitamins are very stable. If you stop taking the vitamins, the body will eventually metabolize them. Not all symptoms are reversible, and I’m not going to bother hunting for more cites. Too much can cause nerve damage is not reversible. I’ll let one of the medical doctors give cites, if they will. As to children or adults, you cite one study in November 2001 wherein 30 children were affected. A medical toxicologist says that children are particularly at risk. They are, but I’ve read throughout the years from various periodicals that it has been adults that have OD’d, thinking if some is good more is better. Children, of course, are more susceptible, but usually it has been the adults who take the supplemental pills. [http://www.health.harvard.edu/hhp/article/content.do?name=L1001c](http://www.health.harvard.edu/hhp/article/content.do?name=L1001c) Unfortunately, I am no longer a subscriber so can’t read the rest of this article, but what is given gives you a hint. [http://www.health.harvard.edu/hhp/article/content.do?name=W0302a](http://www.health.harvard.edu/hhp/article/content.do?name=W0302a) See my comment above, but obviously a hip fracture is not easily reversible. I’ve read that excess D can result in permanent neurological deficits. ---
**Author:** ![barbitu8](https://avatars.discourse-cdn.com/v4/letter/b/839c29/32.png) [@barbitu8](https://boards.straightdope.com/u/barbitu8)\ **Post date:** [May 25, 2004, 1:57am UTC](https://boards.straightdope.com/t/multi-vitamin-pills-and-dosage/246421/15 "2004-05-25T01:57:09Z")
[One more source.](http://www.mayoclinic.com/invoke.cfm?objectid=C620A8C8-C036-44DB-BB2C40719251C79C) [Another.](http://www.mayoclinic.com/invoke.cfm?objectid=F3192866-78DA-4A54-87D577EF14DF6951) > [@](#): > > Side effects: Prolonged intake of vitamin D above 2,000 IU/day poses the risk of toxic effects. Side effects include nausea, headache, excessive urination, high blood pressure, deposits of calcium in soft tissues, kidney damage and other problems. [Yet another.](http://www.mayoclinic.com/invoke.cfm?objectid=CFADFAA6-F1A0-44E2-882950F2F67C5427) > [@](#): > > Side effects: Signs and symptoms of vitamin A toxicity include nausea and vomiting, headache, dizziness, blurred vision and problems with muscular coordination. Most cases of vitamin A toxicity result from an excess intake of vitamin A supplements. Plant sources of beta carotene, which converts to vitamin A, are generally considered safe. A high intake of beta carotene from plant sources can turn your skin an orange color, but this is not considered a health concern. However, the safety of beta carotene supplements is questionable. ---
**Author:** ![antechinus](https://avatars.discourse-cdn.com/v4/letter/a/fbc32d/32.png) [@antechinus](https://boards.straightdope.com/u/antechinus)\ **Post date:** [May 25, 2004, 3:32am UTC](https://boards.straightdope.com/t/multi-vitamin-pills-and-dosage/246421/16 "2004-05-25T03:32:53Z")
**Barbitu8** , it seems we are not in disagreeance. I am pointing out that children are particularly at risk because of their low body mass - thats what this thread is about. A small increase in dose for a child has a more pronounced effect. I said _many_ OD’s have been of children, not all or most. Fat soluble vitamins stay around for a while, but eventually leave the body. You said so yourself: "If you stop taking the vitamins, the body will eventually metabolize them. " I think you will agree that the main point is that most people on a normal healthy diet do not need vitamin supplements and that taken in excess fat soluble vitamins can be dangerous. I agree you can have chronic health effects from an acute exposure to a readily excreted substance or its metabolite - methanol and blindness comes to mind.