the multivitamin efficacy debate
January 21, 2011 11:14 AM   Subscribe

what are the most compelling arguments for and against the efficacy of multivitamin supplements?

it seems opinions about whether or not one will dervive any benefit from taking a multivitamin are starkly divided.

one of the most common arguments i see against them states that the human body can't break down pill and absorb the contents before your body expels it, but they also never seem to talk about whether or not partial absorbtion is ocurring and whether or not this carries a net benefit.

one of the most common arguments i see for them seems anecdotal, "i just feel better when i take one", but is stated often enough that it feels vaguely compelling even though it could still just be a placebo effect.

posted by radiosilents to Health & Fitness (7 answers total) 5 users marked this as a favorite
Did you see this thread and this one when you Googled for this?
posted by John Cohen at 11:18 AM on January 21, 2011 [1 favorite]

People are starkly divided. The medical and scientific establishment is not. If you have a vitamin deficiency, you can sometimes treat that with vitamins, including multivitamins. In this case you are treating a medical problem with a medical solution. Similarly, pregnant women should take folic acid supplements. This is science. So to address your question directly

- the argument for them is that if you have a vitamin deficiency a multivitamin may address it. See your doctor.
- the argument against them is that if you do not have a medical need for them, you are just spending money on a product that is not improving your health and quite possibly thinking you are doing something to improve your health when you are not. See your doctor.

If you don't want to dig through the two threads that John Cohen linked to, I'd suggest this pullquote and link.

"Medline Plus has detailed information on many common vitamins and supplements, and grades each of them on how well they've been proven to address a number of health issues.

Unsurprisingly, the most common grade is "C - Unclear scientific evidence for this use;""
posted by jessamyn at 11:43 AM on January 21, 2011 [4 favorites]

Saw a meta study in which prenatals reduced risk of congenital defects.

Iron treats anemia, so obviously that part has an effect.
posted by the young rope-rider at 11:51 AM on January 21, 2011

Michael Pollan talks about this in his book "In Defense of Food: An Eater's Manifesto." His argument against multivitamins is that real food (meaning real fruits, vegetables, grains, not packaged snacks or TV dinners) has so much more in them than just vitamins. 100 years ago all we knew was that food had carbs, fat or protein, and thought that's all we needed. Then when vitamins were discovered, we thought *that* was all we needed, and put them in pills. Now we are discovering other components of food, like flavonoids and phytochemicals, etc. You can't replicate the exact effect of whole foods just by putting *some* of their components in a pill, because we don't yet know all the components. As an example, a study showed that people who eat foods high in vitamin A had less incidence of cancer. But people who just took vitamin A supplements had slightly higher incidence of cancer. Why? Nobody knows exactly, but it could be because vitamin A works best in conjunction with certain other nutrients that are only in whole foods.
posted by LaurenIpsum at 2:46 PM on January 21, 2011

Funny, had a conversation with a med student a few years ago over a very unhealthy plate of Chinese food about vitamin supplements and he gave the scientific research but he pointed out that all of his instructors took multivitamins anyway. So yeah, weak on the science but high on hedging your bets.
posted by jadepearl at 3:09 PM on January 21, 2011

Apocryphal story, may even be true -- I stopped taking multi-vitamins when I heard plumbers who clean out septic tanks always find their floors strewn with undigested multi-vitamin pills.
posted by Rash at 4:41 PM on January 21, 2011

Pro: Many decades of chemical fertilizer use has depleted the soils of micronutrients, and our vegetables are picked too early and shipped for weeks to reach us - so even a very "healthy" diet is going to be deficient in nutrients.
Con: The low absorption thing. The best solution I know of is to get supplements from a good health food store as opposed to the drug store or supermarket.
Important: Almost everyone is severely deficient in Vit. D, which is normally made in your body in direct sunlight. We live indoors, and when we go outdoors, we were sunscreen now, which blocks vit. D formation 100%. If you are going to take one supplement, take Vit. D as it is not available in adequate amounts in any foods.
posted by grizzled at 6:03 PM on January 22, 2011

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