Notes: Comments specific to women, vegetarians/vegans, people over 50, people with significant health problems such as diabetes or epilepsy, or people taking specific prescription drugs were not included below. So this is most useful for healthy men under 50 who consume animal products. Most of it applies more generally, but which things don't are not marked. It's hard enough to keep track of all this stuff for just one kind of target person. It would have been too much harder to keep track of all the conditionals. People who fall into other categories should consult the sources (listed at the bottom below) dircetly themselves. All doses, intake levels, etc. mentioned below mean daily levels. Comments for each particular nutrient are in no particular order. After going through references [1] - [11], I've found that reference [12] is so thorough that I'm not going to bother copying everything it says about each nutrient. Instead, I recommend for each nutrient in turn, looking at what I've colleced below and also at the corresponding entry in [12] at the same time. Send comments to: kpfleger@cs.stanford.edu ---- water soluble vitamins ---- vit B-1 (thiamin) USRDA = 1.5 mg [3,6] optimal intake = 25-100 mg [11] optimial total intake = 100-300 mg, no known maximum [3] recommended supplement amount = 50 mg [4] probably get enough from diet [1] not necessary to supplement [2,5] a typical multivitamin amount is 25 mg [2] vit B-2 (riboflavin) USRDA = 1.7 mg [3,6] optimal intake = 25-100 mg [11] optimal total intake = 100-300 mg, no known maximum [3] recommended supplement amount = 50 mg [4] probably get enough from diet [1] not necessary to supplement [2,5] big contributer to turning urine yellow [2] a typical multivitamin amount is 25 mg [2] vit B-3 (niacin) USRDA = 19 mg [3], RDA = 20 mg [5,6] optimal intake = 10-100 mg [11] recommended supplement amount = 80 mg [4] optimal total intake = 50-100 mg, may cause side effects above this level [3] probably get enough from diet [1,5] typical multivitamins provide 50-100 mg, risk of liver problems from more [2] vit b-5 (pantothenic acid) estimated safe total daily intake (substitute since no USRDA) = 4-7 mg [3,5] recommended supplement amount = 50 mg [4] optimal intake = 25-200 mg [11] optimal total intake = 10-300 mg, no known maximum [3] most people get enough in their diet [1] no clear reason to supplement [2,5] vit B-6 (pyridoxine) typical multivitamins provide 10-25 mg, more is probably not harmful [2] USRDA = 2 mg [3,5,6] new tolerable upper limit set at 100mg, can cause reversible nevre toxicity above this level [7] optimal intake = 25-100 mg [11] some experts recommend 3-6 mg [5] up to 500 mg appear to be safe [6] doses over 50 mg should be spread over the course of the day [6] recommended supplement amount = 75 mg [4] extremely high doses of 2000 mg can cause permanent nerve damage [5] optimal total intake = 50-300 mg, maximum safe = 500 mg [3] vit B-6 (folic acid / folate) folate is a B vitamin compound, folic acid is a synthetic version that is about twice as potent by weight [5] USRDA = 200 mcg folic acid [3,6] DRI (new version of USRDA) = 400 mcg folate [5] many experts recommend 400 mcg folic acid [5] optimal intake = 400-800 mcg [11] high doses can be bad (but didn't say how high) [5] recommended supplement amount = 400 mcg folic acid [4] optimal total intake = 400 mcg folic acid, no known maximum [3] take <= 400 mcg folic acid [1] vit B-12 (cobalamin) USRDA = 2 mcg [3], USRDA = 2.4 mcg [5] recommended supplement amount = 100 mcg [4] optimal intake = 200-400 mcg [11] optimal total intake = 5-100 mcg, no known maximum [3] no clear reason to supplement [2] biotin (a B vitamin [5]) estimated safe total daily intake (substitute since no USRDA) = 30-100 mcg [3] optimal total intake = 300 mcg, no known maximum [3] some experts suggest 30-100 mcg [5] recommended supplement amount = 300 mcg [4] optimal intake = 200-400 mcg [11] most people get enough in their diet [1,5] no evidence of toxicity in high doses [5] a typical multivitamin amount is 300 mcg [2] optimal intake = 25-100 mg [11] people usually get enough from intestinal bacteria, but may not if antibiotics have killed off much of this bacteria [2] choline bitartrate (a non-essential, unofficial B vitamin) 25 mg is insignificant compaired to dietary amounts [2] recommended supplement amount = 200 mg [4] don't take 20,000 mg [6] inositol (a non-essestial, unofficial B vitamin) recommended supplement amount = 40 mg [4] optimal intake = 25-100 mg [11] essential for some animals, but not proved to be required by humans [1] PABA (para-aminobenzoic acid) (a non-essential, unofficial B vitamin) recommended supplement amount = 50 mg [4] optimal intake = 25-100 mg [11] 25 mg is too small an amount to have significant effect [2] therapeutic dosages are 100s of mg [2] (only hair growth mentioned as benefit) vit C (Antioxidant.) [1] USRDA = 60 mg [1,3,6,10] NIH recommends 100-200 mg [5] optimal intake = 500-5000 mg [10] optimal intake = 500-2000 mg [11] more than 1000 mg may cause in addition to intestinal problems headaches and urinary problems including kidney stones [5] [7, just for the kidney stones] more recent studies of high doses leading to kidney stones haven't been able to reproduce the connection [6] more than 500 mg may have pro-oxidant (instead of antioxident) effects [5] recommended supplement amount = 2650 mg (split into 4 categories) [4] optimal total intake = 100-2,000 mg, above 2000 mg may cause side effects [3] more than 1000 mg causes diarrhea in some people [1] take 250-500 mg [1] therapeutic or prophylactic doses are 1000-5000 mg [2] ---- fat soluble vitamins ---- vit A (Not an antioxident.) [1] listed as "acetate", "palminitate", or "fish oil" [1] USRDA = 5,000 IU [1,3] RDA = 10,000 IU [6] US RDI = 5,000 IU (vit A and beta-carotene) [10] optimal intake = 5,000-25,000 IU (vit A and beta-carotene) [10] optmial intake = 5,000-10,000 IU [11] doses over 10,000 IU should be taken only under medical supervision [6] 10,000 IU or more can cause liver damage [7] supplementation rarely recommended for normal people due to toxicity [5] recommended supplement amount = 5,000 IU (in addition to beta-carotene) [4] optimal total intake = 10,000 IU, maximum safe = 25,000 IU [3] (apply this to beta-carotene instead since beta-carotene wasn't listed separately in [3]) severe problems can develop from long-term intake of 5 times the RDA [5] best to skip altogether and get purely as beta-carotene [1] take <= 5,000 IU [1] vit D / vit D-3 (not really distinguished in these sources usually) USRDA = 200 IU [3,5] (which is 5 mcg [5]), RDA = 400 IU [6,10] optimal intake = 400-800 IU [10,11] extremely toxic in high doses, 50,000 IU causes major problems [5] recommended supplement amount = 400 IU [4] doses above 1000 IU are not recommended [6] optimal total intake = 400 IU, maximum = 15,000 IU [3] take <= 400 IU [1] avoiding it altogether is fine if you get "some" sun exposure daily [2] vit E only nutrient in which natural is better than synthetic, and natural form is d-alpha-tocopherol whereas synthetic is dl-alpha-tocpherol (or -eryl) [1,4] mixed tocopherols are better than just the d-alpha variety alone [4] USRDA = 30 IU [1,5,6,10], USRDA = 15 IU [3] optimal intake = 400-1200 IU [10] optimal intake = 400-800 IU [11] recommended supplement amount = 800 IU [4] some groups recommend 200-400 IU [5] some research now indicates that supplementation provides few benefits and can have pro-oxidant (instead of antioxidant) effects [5] 50 IU can protect against prostate cancer [7] 100 IU can protect against heart disease [7] some experts believe the beneficial form is gamma-tocopherol, not d-alpha as is most common is supplements, and lots of d-alpha can compete with gamma [5] optimal total intake = 200-600 IU, no known maximum [3] take 100-400 IU [1] health benefits are at 400-800 IU [2] vit K estimated safe total daily intake (substitute since no USRDA) = 80 mcg [3] RDA = 70-80 mcg [5] optimal intake = 80 mcg [11] optimal total intake = 100 mcg, maximum = 500 mcg [3] people usually get enough from intestinal bacteria, but may not if antibiotics have killed off much of this bacteria [5] ---- carotenoids ---- beta-carotene (Antioxident.) [1] body converts to vit A, but stops when there is enough [1] recommended supplement amount = 15,000 IU [4] optimal intake = 5,000-25,000 IU (vit A and beta-carotene) [10] optimal intake = 5,000-25,000 IU [11] 33,000-50,000 IU levels have been linked with increased lung cancer risk [7] RDA = 15-50 mg [6] (how many IU is this?) may have pro-oxidant (instead of antioxident) effects in very large doess (but they didn't say how large) [5] vit A optimal total intake = 10,000 IU, maximum safe = 25,000 IU [3] (apply to beta-carotene instead since beta-carotene not listed separately in [3]) Dr. Weil recommends 25,000 IU [2] ---- minerals and other summplements ---- calcium USRDA = 1000 mg [2], USRDA = 1000-1200 mg [3], RDA = 1200mg [6,10] optimal total intake = 1200 mg, maximum = 2500 mg [3] optimal intake = 800-1200 mg [10] optimal intake = 500-1000 mg [11] maximum safe dose = 2500 mg [7] preliminary evidence suggests that even 2000 mg (total food plus supplements) may increase prostate cancer risk in men [7] recommended supplement amount = 1000 mg [4] 25-50 mg isn't a worthwhile amount for a supplement, need more [2] take 1/2 of USRDA (most people get the rest from food) [1] magnesium USRDA = 350 mg [2,3] US RDI = 400 mg [10] optimal intake = 500-750 mg [10] optimal intake = 250-500 mg [11] optimal total intake = 600 mg, no known maximum [3] recommended supplement amount = 500 mg [4] 10 mg isn't a worthwhile amount for a supplement, need more [2] take 1/2 of USRDA (most people get the rest from food) [1] zinc don't take high doses without also taking copper [1,6] doses of 100-300 mg can impair immune system function [6] zinc can help evelate cholesterol (when taken in uspecified doses) [6] USRDA = 15 mg [2,3,6,10] optimal intake = 22.5-50 mg [10] optimal intake = 15-30 mg [11] doses as low as 50mg can impair the immune system [7] optimal total intake = 30 mg, maximum = 500 mg [3] recommended supplement amount = 30 mg [4] a typical multivitamin amount is 15 mg [2] useful for prostate health, 30mg for serious prostate support [2] copper (Oxident.) [1] estimated safe total daily intake (substitute since no USRDA) = 1.5-3.0 mg [3] optimal total intake = 3.0 mg, maximum = 3.0 mg [3] optimal intake = 1-3 mg [11] recommended supplement amount = 2 mg [4] 2-4 mg are probably safe [6] doses of 35 mg are toxic [6] take <= USRDA if at all [1] take if taking high doses of zinc [1] take 10% of amount of zinc taken [2] a typical multivitamin amount is 2 mg [2] potassium 5 mg isn't a worthwhile amount for a supplement, need more [2] optimal total intake = 3500 mg, maximum = 15,000 mg [3] optimal intake = 99-300 mg [11] recommended supplement amount = 99 mg [4] minimum daily requirement is 2000 mg (but no USRDA) [2,3] average diet has 2000-6000 mg [2] iron USRDA = 10 mg [3], RDA = 15 mg [6] optimal daily intake = 18 mg, maximum = 50-100 mg [3] less is better in supplement [1] optimal intake = 15-30 mg [11] iron supplements should only be used when tests show a deficiency exists [6] take <= USRDA [1] avoid it completely [2] manganese estimated safe total daily intake (substitute since no USRDA) = 2-5 mg [3] optimal total intake = 10 mg, no known maximum [3] optimal intake = 10-20 mg [11] recommended supplement amount = 10 mg [4] most people get enough in their diet [1] a typical multivitamin amount is 5 mg [2] not necessary to supplement [2] selenium (Antioxident.) [1] USRDA = 70 mcg [3,10] optimal intake = 100-400 mcg [10] optimal intake = 100-200 mcg [11] optimal total intake = 200 mcg, maximum = 200 mcg [3] doses above 1000 mcg cause lots of problems [6] recommended supplement amount = 200 mcg [4] 200 mcg per day it what people should get including from diet [2] take 50-200 mcg [1] 200mg is the level that may cut the risk of cancer, and the safest way to get this amount is to take a supplement since food levels vary a lot [7] chromium (sometimes with abbreviation "GTF" for glucose tolerance factor) estimated safe total daily intake (substitute since no USRDA) = 50-200 mcg [3] RDA = 100 mg [6] (misprint and should be mcg?) US RDI = 120 mcg [10] optimal intake = 200-600 mcg [10] optimal intake = 100-400 mcg [11] optimal total intake = 50-200 mcg, maximum = 200 mcg [3] recommended supplement amount = 200 mcg [4] take 50-200 mcg [1] some researches believe chromium supplementation can damage DNA and lead to cancer, and thus it should be completely avoided as a supplement [2] average male US diet only provides 33mcg [9] helps improve glucose tolerance and ward off diabetes [9] helps lower cholesterol [9] adequate daily intake 50-200mcg according to National Research Council [9] molybdenum USRDA = 75-250 mcg [3] optimal total intake = 250 mcg, maximum = 500 mcg [3] optimal intake = 10-30 mcg [11] recommended supplement amount = 125 mcg [4] most people get enough in their diet [1] too much more common diet problem than too little, so avoid altogether [2] phosphorous USRDA = 800 mg [3] optimal total intake = 1200 mg, no known maximum [3] most people get enough in their diet [1] chloride most people get enough in their diet [1] iodine USRDA = 150 mcg [3,6] recommended supplement amount = 150 mcg [4] optimal total intake = 150 mcg, maximum = 2 mg [3] silica / silicon (same thing?) not sure which: recommended supplement amount = 25 mcg [4] not sure which: optimal intake = 200-1000 mcg [11] not sure which: essential for some animals, not proved essintial for humans [1] silicon: is not essintial for humans [12] silicon: average diets provide 5-20 mg [12] silicon: common supplement amounts are 1-2 mg [12] silicon: high dietary intake not associated with toxicity [12] boron helps prevent loss of Calcium and Magensium [8] there is still debate about whether it is essential in humans [12] optimal intake = 1-3 mg [11] diets in some places in the world consist of up to 41mg of boron without apparent adverse affects [8] a leading boron expert recommends 1 mg supplementation [12] people with diets rich in produce, nuts, and legumes are consuming 2-6 mg [12] 1-3 mg intake has not been linked with toxicity [12] levels don't accumulate in the body [12] 3 mg intake has been linked with increased estrogen which may cause elevated risk of cancers, so some doctors recommend a maximum of 1 mg intake [12] boron interaction with other minerals is poorly understood and some studies suggest that the benefit for retaining calcium disappears when enough magnesium is consumed [12] vanadium essential for some animals, but not proved to be required by humans [1,12] optimal intake = 50-100 mcg many doctors believe that 100 mg intake will be shown to be unsafe [12] no deficiencies in humans have been reported and are believed unlikely [12] "research indicates that most people would not benefit from vanadium supplementation" [12] optimal intake unknown, estimated requirement = 10 mcg, but average diet provides 15-30 mcg [12] more info on the following (and many other supplements) can be found in [12]: 5-HTP (tryptophan) bee pollen betain HCl (hydrochloric acid) bioflavonoids (including quercentin, rutin, and citrus bioflavonoids) chlorophyll coenzyme Q10 (CoQ10, ubiquinone) creatine DHEA fish old / cod liver oil / omega-3 fatty acids ginkgo biloba glucosamine sulfate and chondroitin sulfate lutein kelp melatonin MSM (sulfur) N-Acetyl Cysteine (NAC) spirulina (blue-green algae) ++++ general issues ++++ many bottels have expiration dates, don't go past them [1,4] carbonate and oxide forms of minerals have lower absorption rates than malate, ethanolamine phosphate, ascorbate, citrate, fumarate, peptonate, succinate, sysinate, glycinate, picolinate, and acetate [4] store supplements in cool, dry, dark place [4] ("cool" I have discovered means below 86 degrees F, which can be an issue in the summer or in warm climates if you don't have air conditioning, especially in sun-facing rooms; bathrooms and kitchen are both bad for their humidity) take supplements in divided doses multiple times per day [4] sometimes gastrointestinal side effects (such as diarrhea) with large but safe doses (like lots of vit C) will go away if the dosage is graudally increased to give the body time to get used to it [4] ==== references ==== These references are numbered in the order in which I encountered them and incorporated their comments above. Most of these articles and web pages themselves reference articles in scientific and medical journals, so if you want to go to the real sources you can follow the citation trail. In case any of the referenced web pages is moved or removed, I have cached most of them at www-cs-students.stanford.edu/~kpfleger/multivitamins/cached/ If you only look at once of these sources, [12] is very comprehensive dealing extensively with all common supplements and providing numerous pointers to underlying scientific articles. [1] "Vitamins 101: How to buy them" by David Schardt, _Nutrition Action Healthletter_, not sure when, but definitely before 1994. [2] "Multivitamins - save your money for better purchases", www.cockatoo.com/multivitamin/, updated sometime after Feb 1999, cached 2/5/2000. [3] www.mothernature.com/cg/multi_vitamins.asp (note that this source is a supplement store), cached 2/5/2000. [4] www.healthydirections.com/hdi_getstarted (note that the author of this page is pushing his own supplement), cached 2/5/2000. [5] my.webmd.com/content/dmk/dmk_article_40088, cached 2/5/2000. [6] my.webmd.com/content/dmk/dmk_article_58947, cached 2/5/2000. [7] "Do you know your vitamin ABC's" by Bonnie Liebman, _Nutrition Action Healthletter_, Sept. 1999, http://www.cspinet.org/nah/9_99/vitamin_abc.htm . [8] "Skeletal Health Through Nutrition", Jarraw L. Rogovin, pre-1994. Something I had a hard-copy of. [9] "Chrunching Some Chromium May Improve Health", by Dave Ludwig, _Men's Health Magazine_, pre-1994. [10] http://www.vitamins.com/about/site/dosages.html (note that this source is a supplement store), cached 2/8/2000. [11] http://www.vitamins.com/about/site/optimal.html (note that this source is a supplement store), cached 2/8/2000. [12] http://www.vitamins.com/encyclopedia/Index/SUPPX.HTM or http://www.puritan.com/scriptsp/htmlos.exe/05219.4.465611743500005719/puritan/mainnew.html (While these web pages are hosted by a supplement store, this information appears to be unbiased with plenty of scientific references cited to back up the claims made and a lot of reporting that no clear evidence exists in favor of supplementing many of the nutrients. They are prepared by an outfit caled HealthNotes (www.healthnotes.com) specifically for licensing to other websites. I can't cache the whole thing easily as it's a collection of documents, but I cached the excellent page specifically about multi-vitamin/mineral supplements (http://www.vitamins.com/encyclopedia/Supp/Multi_Vitamin.htm) on 2/9/2000. The vitamins.com site seems to have gone away, but the other site still has this content.