Just curious. Wiki link was a bit inconclusive re how science views this theory. For years many foods have been touted (often by doctors and nutritionists) as good or bad for you because of their impact on the free radicals in your body. Is this considered an actual verified theory or not?
As kind of an addendum to your question, I’d like to throw in the idea that the lack of telomeres (genetic padding that gets used up when your cells multiply) played a part. If free-radical theory is accepted, how does the telomere thing fit in?
I have always heard the term ‘free radicals’ used analogously to talk about social undesirables- the pot-smokers and non-church goers & etc. As if to say: we have this wonderful body politic here, and you <insert epithet here> are killing it.
I can’t speak to the science, but maybe this anecdote fills in the picture a piece.
Per your link:
Free radicals cause oxidative stress. BTW, telomeres are not “padding,” but essential for mitosis, and as the article states, they can be likened to shoelace tips, insofar as their locations are concerned.
One would also have to add in the cancel out effect. If free radicals are indeed bad, there are other substances that abosorb them and can counter their effects. Therefore if they are that bad, the question becomes can you simply eat substances that will cancel their effects or must they be avoided all together?
You can’t avoid free radicals all together. Even if you had a diet that contained none, your cells are constantly producing a certain amount as metabolic byproducts.
As to the OP… I don’t think anyone seriously refutes that free radicals exist or that they are bad for you as one component (among many) of aging. As far as I can tell, the main dispute is over how significant a component free radicals are, and whether drinking product X for $50 a week will extend your life by even a second.
It’s a funny thing about free radicals. The compounds that absorb free radicals become free radicals. The “anti-oxidants” usually form very stable and relatively benign free radicals, but they are still free radicals. The only thing that can destroy a free radical, is another free radical. A free radical, is very simply a molecule with an unpaired electron.
Exercise creates more free radicals; however, exercise also produces antioxidants to absorb the free electron. Since an antioxidant incorporates the electron in its molecule, how is there another free radical produced? (Studies show that those who exercise at least moderately live longer, all other factors being equal.)
You answer your own question of course. The anti-oxidant absorbs the electron. Now the anti-oxidant has an extra electron. For the most part these are pretty benign, but excessive anti-oxidants may do more harm than good. I vaguely remember a study to that effect. I’m not disputing that anti-oxidants are generally good.
Is it a valid theory? Absolutely.
Here’s a relatively recent review (free full text) from a reputable journal which describes ‘free radicals’ and ‘oxidative stress’ as a legitimate theory of ageing (senescence) with “growing support among scientists” with “significant evidence” underlying it.
An anti-oxidant can receive an electron from one free radical and receive a second electron from a second free radical, leaving no free radicals. From one point of view the original free radicals destroy each other, but it wouldn’t happen at that rate without an antioxidant. Apparently ascorbic acid works that way.
I am fairly sure I heard somewhere recently (probably on NPR, so no cite, sorry) that none of the studies of people taking antioxidant supplements (mostly various vitamins) have found any sign of any actual health benefits. The researchers were apparently a bit baffled by it, because they did seem to be convinced that free radicals (or too many, anyway) are bad, and that the antioxidants reduce them, but somehow the effects were not showing up in improved health or longevity.
Some years ago, my doctor advised me to take antioxidant supplements (vitamins C, B complex, and E specifically) to help lower my cholesterol. After hearing about the above I asked my current doctor if I should keep this up, and his answer, basically, was “don’t bother.”
I also think I heard somewhere of a study suggesting that although they do have their dangers, free radicals also have some benefits, so you do not want their levels to be too low. (I can’t remember any details about this though, so I may have it wrong.)
As usual people are throwing around terms without any definitions.
Is free radical theory real science? Yes, it is. Is it correct science? We don’t know yet.
Lots of things that are real science turn out not to be correct after a thorough investigation. That doesn’t make the science not valid.
Verified is not a meaningful word, either. What does verified mean? That some studies have confirmed it? That the current consensus confirms it? That it is one good potential venue of investigation for a subject that nobody knows the answer to yet?
Nobody knows what causes aging. Period. Nothing is verified.
Moneypenny: Have you got a mission, James?
Bond: Yes. I am to eliminate all free radicals.
Moneypenny: Ooh. Do be careful.
Ah, ok, that’s clear then. :rolleyes:
Well, if you know the answer, for Pete’s sake, tell the rest of us, fast. None of us are getting any younger while you make us wait!
I am too sick to find the cite, but I the hypothesis on aging and free radicals was shown with individuals with progeria whom age at an accelerated rate.
Its pretty easy for your body to make free radicals. Did you know your immune cells synthesize bleach? 
Now THAT’s a radical. But seriously, free radicals are needed for stem cell differentiation.
Also to the point, is that many of the complications of diabetes such as cataracts, atherosclerosis (“hardening of the arteries”), neuropathy (“nerve damage”), nephropathy (“kidney damage”), and retinal disease, resemble the manifestations of advanced age. That is interesting since free radical generation and oxidative stress is now felt to play a significant role in causing those complications. Cite.
Phrased more concisely, diabetes leads to accelerated ageing through a mechanism that involves oxidative stress.
Let’s all be nice.
I think the point is that although the question was somewhat ambiguous (what does valid mean?), there are only a couple of possible interpretations, and the general scope of discussion is clear enough. “What is the status of the hypothesis…” is a legitimate question, and perhaps more can be said than “we don’t know for certain”. And general points that veer into philosophy of science may not be so helpful.