I like taking vitamins to supplement what I don't get from eating a Paleo-ish diet.
A highly publicized study about a year ago (< http://www.livescience.com/health/090209-multivitamins.html >) seems to have demonstrated strongly that multivitamins don't work.
What is the most likely (and paleo-consistent) explanation for this?
I'm not sure the usual/obvious the "vitamins are better from natural sources" argument is strong enough - of course that's true, but plenty of other vitamin supplements do work, so this argument doesn't make sense to me. Thoughts?
asked byMorgan (1670)
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on March 07, 2010
at 11:11 PM
- Vitamin pills contain small amounts of many vitamins and minerals. On average, this is really no different than food.
- The real value of supplements comes with correcting or preventing deficiencies, such as taking extra selenium when the soils around where you live don't have enough, or vitamin D3 when you don't get enough sun. Measuring and targeting deficiencies greatly adds to the usefulness of supplements.
- Many brands of vitamins contain small amounts of toxins that could easily offset whatever value is obtained from the vitamins themselves. Rancid oil in capsules is an example. This can be remedied by using only high-quality brands.
- The quantities offered in multivitamins have to be minimal (often truly microscopic amounts), simply in order for them to fit in a single pill. Many minerals, in particular, require a reasonable quantity to be effective.
- The form of vitamins and minerals used in the more popular brands tends to be the least expensive type, which is also often not very absorbable (such as magnesium oxide).
- The capsules or coatings used on some multiples don't dissolve very easily. Particularly in people with low stomach acid, who need supplements the most, the pills sometimes pass through the body without even dissolving.
on March 08, 2010
at 03:36 PM
Interesting article on the subject:
from PNAS: Antioxidants prevent health-promoting effects of physical exercise in humans, by Ristow et al
from the abstract:
Consistent with the concept of mitohormesis, exercise-induced oxidative stress ameliorates insulin resistance and causes an adaptive response promoting endogenous antioxidant defense capacity. Supplementation with antioxidants may preclude these health-promoting effects of exercise in humans.
Interesting read, should be available here: http://www.pnas.org/content/early/2009/05/11/0903485106.full.pdf+html
on March 07, 2010
at 04:30 PM
I think the most likely explanation involves both availability and synergy.
Supplements can include a vitamin or mineral, but they are more or less available to us depending on the form. And what's easy (or cheap) for the manufacturer may be not so useful to us. For example, vitamin D needs fat to be absorbed, so if you're taking it as a pill on an empty stomach, it won't be too useful to you.
The other is synergy. Vitamins and minerals don't act in isolation, so taking lots of one without a necessary complement may not be useful. Calcium and magnesium are an example of this. The other issue is that foods probably contain potentially unidentified micronutrients that also complement a known nutrient. Resveratrol might be an example of this. It was supposedly the hero of the French paradox, but tests using it as a supplement on its own haven't been overwhelming. Is it the supplement? Or is it something missing from the mix?
on March 07, 2010
at 11:05 PM
This is the article that pushed me over the edge in thinking a good quality multivitamin is a great low-risk 'insurance policy':
It is by a supplement manufacturer however :)
on April 02, 2010
at 02:09 AM
I think part of it is actually that the vitamins do not com from natural sources. Just like the frankenoils are bad, man-made vitamins can be bad. Also, since there are a lot of vitamins and minerals in a small space, like Beth said, you don't always get the dependencies.