Antioxidants prevent health-promoting effects of physical exercise (2009) [pdf] | Hacker News Reader

Antioxidants prevent health-promoting effects of physical exercise (2009) [pdf]

pnas.org

116 pointsgregwebs39 comments

A controversial topic .. there is an effect called mito-hormesis .. when you do excercise there are small amount of free radicals leaked that activates kinases and inhibits phosphatades and overall increase phosphorylation in the cell. Through this and other pathways, some genes are expressed which are supposed to increase survival, so overall there is a window of free raficals concentration. If you get below it (total blockade) you will prevent the hormesis (beneficial) effect, but if you get above it, you can get all the free radical related diseases e.g neurodegenerative diseases.

[0] https://doi.org/10.1038/nm.3624

what's the status quo on hormesis acceptance ? I've read countless time that the originator is controversial and over-fit his theory .. but at the same time positive/antifragile feedback mechanisms seem so obvious.

Are you thinking radiation hormesis? That is still controversial and current radiation safety standards adhere to "no safe dose of radiation".

But hormesis as a general theory (i.e. "small doses are beneficial, large doses harmful") isn't really that controversial.

I remember a lot of time reading people saying the general theory is fluff because too general.

I am not an expert on the ageing-related hormesis topic and have not kept up with status quo but this was the most recent and interesting interactive lecture I enjoyed this year on the topic:

https://youtu.be/zjQ5Z7v6csk

> Taken together, these previously published findings tentatively suggest that fruits and vegetables may exert health-promoting effects despite their antioxidant content and possibly due to other bio-active compounds. However, it should be noted that the current study applied comparably high doses of oral antioxidants, which have been tested in healthy young men only.

In short: it is possibly a good idea to eat and drink (at least some teas with goji berries etc.) only after exercise, if you are trying to maximize its health effects.

I just wanted to point out that another comment came to the opposite conclusion, it's unclear to me who is right.

Yeah, not immediately after. The phrase they used is better, "outside of the recovery window". It's all hearsay handwavey stuff anyway until replicated. What I like is that it sort of concurs with the default wisdom of pre scientific/quantified self era paranoia about best practices, which was "don't eat right before exercise". People take this stuff way to seriously IMHO. If you need a scientist to tell you when to eat, you've got bigger problems.

Well, the problem that exercise supplement marketing has created is that they try to convince you that their products, like pre- and during-exercise drinks, are helping you. Otherwise your default state would have likely stayed at bringing just a water bottle and empty stomach to the gym.

Having been in the supplement industry before software, even I ended up confused about what the right approach was. It was clearly awash with psuedoscience, but there are also countless points of anectodal evidence in the community confusing things further.

I no longer take supplements, but creatine and whey protein are the two mainstays in the community. Pure and plain, and with lots of old and new studies backing them up.

2009 paper. No subsequent followups studies since then?

Here is a 2020 review of more recent studies: https://www.strongerbyscience.com/antioxidants/

This is what makes biology so interesting and challenging. You find some biological signal associated with a disease and think "oh, I can just inhibit this and solve the problem!", then you learn there are half a dozen other signaling pathways that rely on that molecule, including beneficial ones.

It reminds me very much of coding, where people strive very hard not to have this type of coupling, but it inevitably still happens.

It's not surprising, since biology tends to reuse existing mechanisms and molecules for lots of different purposes; a result of the fact that we were created through a messy process called evolution.

Further links on that antioxidants inhibit exercise adaptation: https://suppversity.blogspot.com/2013/10/antioxidant-supplem...

https://suppversity.blogspot.com/2014/03/anti-oxidants-resis...

TLDR: Take your antioxidants outside of your workout and recovery window.

The bodies response to working out is based on the challenge/damage and antioxidants reduce that.

Strange notion, that more insulin sensitivity is always better

When would it be harmful?

likely in a subset of cases of reactive hypoglicemia

I'm not sure they are asserting that. In the context of managing or reducing rates of type-2 diabetes, it seems relevant.

this study mentions "healthy young men" and the title states "health-promoting effects". So, do healthy young men need to have their health promoted by increasing their insulin sensitivity?

"More insulin sensitivity" is better because that means that the body can better respond to sugars in the blood.

If you become insulin unsensitive this means your body cannot properly respond to sugars in your blood.

Sugars in your blood corrode blood vessels etc...if they are not removed.

So "more sensitivity" in this case is a good thing.

Maybe some dont like to hear this, but publishing in PNAS is usually when your publication is rejected from other more respected peer-reviewed journals. I wont trust this publication much.

Either way, the only actionable morsel I think anyone could take from this if such a person existed is that they probably don’t need to buy Cytosport’s expensive Muscle Serum(tm) and rip it mid-workout, something that probably does the average person no good anyways beyond turning their piss neon green.

Not that anyone changes their life over a scientific paper. The other year I read part of a frightening paper on heart disease that had me google “how to prevent atherosclerosis”, and later that day I stopped through the McD drive-thru just for three large fries.

Gonna have to come at something a little harder hitting than science to inconvenience me, baby!

Bizarre comment - are you taking the old PNAS = "Passed over by Nature And Science" joke a bit too literally?

PNAS is one of the top general-science journals. Yes, there are better field-specific journals, but PNAS is pretty damn respectable and not that easy to get published in.

Regardless, a publication should be judged on the strength of its research, not on which top-tier journal it is in.

Nature and Science. Ha. If "good" journals stopped with Science and Nature, I wouldn't have published anything yet. Lots of solid science won't even get considered at those journals.

I have heard better arguments in scientific discourse ;-)

Given that vitamin C supplementation is generally understood to inhibit some training adaptations (e.g. reduced skeletal muscle growth), it sounds reasonable to me that it might also prevent insulin sensitivity improvements.

Insulin triggers glycogen synthesis and muscles are one of the places where this happens. Reduced muscle growth -> reduced change in glycogenesis capacity.

What’s the deal about vitamin c and muscle growth? Can you suggest further reading?

What’s the best way to take vitamin c then? Load up on off days, skip on training days?

I like taking 1000mg/day for the gum health benefits and cold prevention.

I recommend searching for "vitamin c training adaptation" on Google Scholar. You'll get a few results plus a list of citations for each result (click "cited by"). The citations help to put each paper into context.

The general idea is that high doses of antioxidants influence cellular pathways that are usually triggered by the presence of reactive oxygen species. The vitamin C reacts with the ROS before the body can build up a response.

I'm not a coach or nutritionist, I can't give a good recommendation. I think the trend goes towards supplementing as little as possible and instead eating enough fruit and whole foods. The body is extremely complex (check out http://biochemical-pathways.com/), supplementing with high dosage might have consequences we don't understand yet.

Personally I stopped taking vitamin C a while ago and have not noticed a difference.

"Dylan Johnson" is a coach who gives science-based recommendations, he has a video on Youtube about vitamin C.

PNAS is a well respected, high impact journal. Impact factors aren't everything, but:

2019 Impact Factor: 9.41

There is no nice way to say this, but your comment is ignorant. I can’t imagine anyone who has published anywhere making this comment

Could you please help me out with a method for how can I determine a paper's legitimacy in a field I'm not familiar with?

What is a good impact factor for the publiching journal?

What is a good # of citations?

What other factors should I check?

Its a little complicated when it comes to impact factors and sub-discipline journals. In my field, specialized journals on developmental psychology, highly respected journals have an impact factor around 4 or 5, like "Child Development" Psychology journals with impact factors around 2 to 3 are kind of the journals you publish in after trying others first, or if you just have a little study that needs publishing, but the results were not that interesting, or if there are some more serious issues in the design, but still worth publishing, etc. In the past I automatically suspected any journal with an impact factor less than 1 or 2 as being trash, but, it has recently come to my attention that there are highly respected journals with really low impact factors, just because it publishes on a highly specialized subfield, and thus don't get cited as frequently. So all in all, as an outsider, it can be a bit difficult.

One possible way is to refer to SJR rankings by discipline: https://www.scimagojr.com/journalrank.php?category=2801

but this still fails for the extra specialized journals.

Another possibility is to look at what authors are publishing in the journal. Are they from major research Universities? etc.

But for a general rule of thumb: any journal with an impact over 2 is a legitimate journal, and any journal with an impact of 6 or more is a very solid journal, 9 up are considered top tier, 14 up are elite tiered.

Just look at that bizarre title: "Antioxidants prevent health-promoting effects of physical exercise" I mean come on!! How can such a generalization be allowed. I was lucky to study in a great lab, my name is on several papers Nature, Science, Nature Medicine and others. PNAS was always our last resort

Are free radicals always shown to be bad? Maybe too much "protection" prevents necessary cell death. Maybe the free radicals are there on purpose.

Then why do I crave a large glass of freshly made orange juice after workout?

Sugar.

And water.

Exercise naturally makes your body better at anti-oxidizing. Maybe consumption of too many antioxidants causes that to atrophy.

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