Leah:
Hello and welcome to the Ideal Nutrition Podcast. I am Leah Higl and I’m here with my co-host Aidan Muir and in today’s episode, we will be discussing whether having antioxidants around training can have a negative impact on your performance and progression in whatever activity that you’re doing. So traditionally antioxidants are thought of as a good thing, reducing oxidative stress, just generally being a healthy thing to include in your diet.
There are some promising links between antioxidants and training, such as a reduction in DOMS or delayed onset muscle soreness. But there are also theoretical reasons why they could have downsides specifically placed around your training for both endurance and hypertrophy. The simple logic here just comes down to that whilst we normally think of antioxidants being a good thing and reduction of oxidative stress being a good thing, and then its impacts on reducing inflammation.
That could also potentially be a negative thing given that inflammation and oxidative stress plays a role in the stimulus for adaptation. So if we are consistently reducing these things, could that then reduce the amount of adaptations that we’re making from training? So theoretically, while someone could be less sore and feel more recovered, in theory, they may make less progress than someone who isn’t having these high dose antioxidants around training.
This is a very complex topic. Aidan and I were just talking off air about how many different nuances go into this discussion and it’s a lot and it’s like a deep area of research. So there are a few things to consider here that we’ll go over in a bit more detail, but that includes what kind of dosages we’re talking about, whether we’re talking about antioxidants from food or from supplements.
And then also the big rabbit hole of what antioxidants are we talking about? Cause we’re casting a pretty wide net. If you’ve seen people talk about things like carotenoids, polyphenols, flavonoids, flavonols or flavones, these are all types of antioxidants. And there are also over 4,000 flavonoids just alone. So you can see how big this space can get and that we probably need to be pretty specific when we’re looking at outcomes.
Aidan:
Yeah, it’s a huge space. I feel like obviously over the years I’ve read so much about this space, but obviously in prep for this podcast, it’s like, there is so, so much reading to be done in this space. Like, it’s absurd. Just cause like, as you can imagine, like what is, yeah, you could just go down so many rabbit holes, but let’s start with some simple stuff. Cause we want to keep this simple. We’re going going to start with some positives.
So the thing you mentioned about reducing soreness. Seems to be pretty consistent, pretty consistently positive. The simplest area of research in antioxidants, in the antioxidant space is vitamin C and vitamin E, which are both antioxidants. For delayed onset muscle soreness, they have mixed but slightly favourable research. I would also speculate that stuff like dosage comes into play there. Like I am sure I may have mentioned this previously on podcasts in relation to like illness and stuff like that, but injecting vitamin C gets you to higher blood levels than just having it orally because it’s the limiting factor.
You can go significantly higher. So I’m like, if vitamin C was inconsistently positive for reduced soreness, what if you were injecting? I’m not saying that’s anything I actually do with any athletes because I don’t have any interest in that, but that would be one thing I’d speculate. But other areas are much more positive than vitamin C and vitamin E And usually these are polyphenols. So, the most common one that I use for people is tart cherry juice or tart cherry extract. Either of those are equally fine.
And that’s got some pretty consistent research highlighting how it can reduce muscle soreness likely due to this antioxidant effect. There are so many other options in that space. So like there’s pomegranate juice, there’s watermelon juice, and they’ve all had similar outcomes. This could be related to antioxidants. The watermelon juice could also potentially be related to citrulline, which if not putting that in the antioxidant category, that could just be from improvements in blood flow. But the more you look at this space, the more you’re like, okay, there’s so many different options here that seem to reduce muscle soreness.
Leah:
Other positives that we can talk about as well include two main examples of very specific supplements. So we could look at things like beetroot juice. So that can be used two to three hours before a session, race, whatever it may be to improve both endurance and performance in things like high rep gym work could be particularly beneficial.
This is mostly due to the nitrates in beetroot juice and concentrated beetroot juice, but beetroot juice is also really high in polyphenols as well. This is like in terms of beetroot juice and where it’s recommended, it is typically more so in the lead up to an event and the day of an event so that you can have that performance output on the day as opposed to habitual intake for every single session.
So when we’re looking at this research and the improvements in research, typically it is that acute benefit from taking it for a small period of time rather than looking at habitual intake around sessions. So it’s hard to say whether if it was used in that secondary way, if it would have maybe a negative impact on physiological adaptations from training. Because usually in the lead up to an event and on event day, we’re not really looking to make physiological adaptations still, we’re just wanting to have the best performance for the day.
Example two would be New Zealand black current extract, which again is high in antioxidants, specifically anthocyanins, which have been proposed to help sports performance due to reducing oxidative stress, and inflammation, and also improving vasodilation. So a little bit similar in terms of the same as beetroot juice. This has led to 1 to 2% improvements in race times on average in the research when used daily leading up to events. So again, it’s in the lead-up to and on the day, but not necessarily looking at habitual intake around a bunch of people’s training sessions.
Aidan:
As you can imagine, this whole kind of acute benefits thing also makes interpreting this research even more difficult, because we’re going to be talking about training adaptations now. But because there are some of these things that have like benefits, like you’ll be reading research on like, antioxidants and it seems all over the place being like this seems to improve performance but then like was that just an acute study?
Other stuff that sometimes isn’t reported in these studies as well is when the last dosage was applied like was the beetroot juice had two hours before the session or was it like a day before the session and that obviously applies to acute research in terms of short -term improvements but what about the long -term stuff about being like what if they were having antioxidants daily but it was 10 hours away from training?
Like then it seems less relevant, but we’ll go through the training adaptation things because the mechanisms as discussed earlier make it seem like it should be detrimental. There’s a lot of particularly animal research, like a lot of rodent research, particularly on endurance athletes. It makes it like seem super clear even in hypertrophy stuff as well, which we’ll talk about later. But what does the research actually show? Like what does the outcome show? So the simplest stuff is done on endurance athletes or the most, most of the research we’ve done on endurance athletes.
The simplest one though is vitamin C and vitamin E once again. This isn’t meant to cover everything, but as we said, it’s like 4 000 plus different types of flavones. Like it’s an endless list. So like simplifying down makes it a little bit simpler to try to wrap our head around it. Of the nine studies we have on vitamin C in this endurance space, fitting the criteria of using dosages of greater than one gram per day and taking it for over a week, four showed impairments in performance over time versus placebo.
Another four were not statistically significant, but showed small impairments versus placebo and one was positive. So eight of nine showed impairments, one was positive. It’s getting kind of compelling. Getting kind of compelling to me like, okay, this probably doesn’t seem like a good idea. Particularly once you factor in that reductions in soreness might even help training if there was no downside whatsoever. So the mechanisms start to line up a little bit. If you were interested in just like fact checking that, looking at that yourself, go to our show notes, because there was a 2023 review titled Antioxidants and Sports Performance. You can find our show notes or you could just Google that as well.
You will notice that they actually worked slightly differently to how I worded it. You won’t find that exact same wording, because there’s a section where they’re talking about 12 studies, which is kind of what I’m quoting from that section. But three of those studies were less than a week long. So I’ve just excluded those because I’m like, that’s not what we’re talking about. We are talking about longer-term progress.
Yeah, obviously we need significantly more research in this space. Like I, I am saying, Hey, it’s getting kind of compelling, but I’m also not like nail in the coffin, antioxidants are in the time of training, clearly a bad thing, particularly because all I just talked about that was vitamin C, vitamin E. And then a lot of those studies like not huge impairments either, but my interpretation for now is that I would have caution around high dose antioxidants, supplements around the time of training when the goal is adaptation.
There are exceptions to that. For example, if somebody’s in a competition phase where they might happen to have a lot of competitions close together, I might take advantage of the reductions and so on and so because I’m like, I don’t care about adaptation at this point. But when we do care about adaptation, I’m at a point where I’m like, I’d probably keep this a little bit separate for something like those specific supplements.
Leah:
Let’s talk about lifting stuff. Let’s talk about that. Okay, we’re coming to the end of the podcasting day. Let’s talk a little bit about lifting specific things. So, specifically in regards to hypertrophy, which is something that I’m super interested about. You’ve changed lanes a bit to running, but it’s still something for sure you care about. It’s my main focus from a professional perspective. Yeah. So from a hypertrophy point of view. So just like in the endurance world, research looking at mechanisms has found that antioxidants can inhibit anabolic pathways. So anabolic being growing hypertrophy.
A 2020 systematic review involving nine studies on vitamin E and vitamin C on resistance training found almost no difference in muscle growth, but it was a tiny bit in favour of those vitamins instead of placebo.
Aidan:
I want to jump in on that as well because like before any awareness of that systematic review, actually in 2019, I reckon if you asked me the question in 2019, should we avoid antioxidants around the time of lifting? I would have said with quite confidence, quite high confidence. Yeah, we should avoid those. Yes. The research is like solid. And then when I found out about that systematic review, I was like, hmm, this is not as solid as I thought. There’s more nuance there. But a lot of people in the evidence based space were saying with a lot of confidence, you need to avoid this because of these mechanisms. And I think a lot of people just repeating each other and not actually going and doing the work and like finding the original studies that actually looked at outcomes.
Leah:
Yeah, I remember the same thing and even hearing it from like really high level senior sports dieticians that were in the research space and I was like, surely they know what they’re talking about. And then we kind of had this systematic review come out and I was like, okay, maybe in endurance, it’s a little bit more clear but hypertrophy, a little less clear. Stronger by Science did a really good breakdown on this highlighting the flaws in how three of those studies were actually just like one experiment that had the data used in three separate papers. So it can look a little bit more compelling than it is knowing that that data was being used several times in that that one review. They also highlighted that the accuracy of measuring things with something like a DEXA scan, whilst like DEXA scan is like the gold standard, there are definitely differences between DEXA to DEXA just in terms of accuracy. It’s not 100%.
So when we’re talking about very small changes in hypertrophy and muscle building, like it could be down to differences in the DEXA scan, not necessarily actual physical differences in the people partaking in these studies. So interpreting it can be a little bit trickier when thinking from that perspective.
Aidan:
Jumping in on the DEXA thing as well, like reading those actual studies, some of these studies had differences of like 1 .5 kios of lean mass gain versus 0 .5. Yeah. And if we took the readings with 100% accuracy, we’d be like, that’s three times the rate of muscle gain. Like, that is statistically, like, even if it’s not statistically significant, like that’s significant, like I care about that. But when there are some questions about like, could DEXA like there is a little bit of margin of error with DEXA, like, and even if there’s not margin for error in the machine, it’s also just being like, what if somebody had slightly higher glycogen stores and that accounted for the difference in lean mass. For these small differences, it’s kind of actually hard to tell. Obviously we do the best with the information we’ve got, but that’s some other thoughts that were added onto that as well.
Leah:
Yeah, I think having some longitude and really long -term data, maybe looking at athletes every year would be nicer than maybe 12 weeks in these cases. But unfortunately, we don’t have any of that, I don’t think. So another review looking at antioxidants and resistance treating demonstrated that on average research found small impairments to hypertrophy. So that’s interesting. They also noted that these impairments were of larger magnitude in younger lifters as opposed to older lifters.
If that turned out to be true and something that we saw more in the research, some logic that you could use behind that could probably be based on that older lifters would have a higher baseline of oxidative stress as opposed to younger lifters. So potentially that’s why there could be that discrepancy there. It also appears that some antioxidants are more likely to be relevant for this than others. So we know this is a huge space. So many things fall under the antioxidant umbrella. These authors appear more concerned about vitamin C and E rather than things like polyphenols, flavonols and anthocyanins. But again, something to consider when looking at this research.
Aidan:
Something that is interesting and I’m not at a point that I fully buy into it because there’s just more research that’s needed, et cetera, et cetera. But the whole older lifters versus younger lifters thing, huge if true, if it is true, I’m like, that’s cool. That’s relevant information. One thing that sucks about oxidative stress and inflammation as well actually is a business saying that I kind of like is what gets measured gets managed and you can see that in so many different areas of business, but that also applies to nutrition. That also applies to training, all of these things. Like sometimes you start measuring something and it’s easier to manage.
One thing that sucks is we don’t measure inflammation and oxidative stress. It’s hard to do that. And even like, say you’re like, I want to start measuring inflammation. You might start measuring like CRP and other blood markers, but like, does that really line up with what you care about? Like some people will have a sore knee and they’re like, I’ve got inflammation in my knee. And the goal is just less pain. The goal is just less pain is not necessarily less inflammation. And that’s actually the thing being measured.
But we know that going too low inflammation would be a bad thing because that’s partly to be honest, what we’ve talked about here just being like, what if that takes away the stimulus for adaptation? What if we know that the body uses inflammation for healing? So we know going too low could be a bad thing. We know going too high could be a bad thing. But the one thing that sucks about this space is that we can’t measure the sweet spot.
And that older versus younger lifters thing makes sense because you’re like, they might have higher levels of oxidative stress. This might matter more. But then if that concept applied, it’d be sick if we could just measure everybody. Let’s get this sweet spot. Unfortunately, we’re not at that stage, but it’s like, I don’t know, interesting to me. We are now gonna just like go a little bit through our interpretation. So personally, I see absolutely no issue. We’re trying to get as many antioxidants as you can through food.
I’ve never seen somebody run into issues with this type of stuff through eating too many fruits and vegetables. Never in research have I identified any of these issues. I can see where the logic comes into play, particularly around supplements And you could say that this is a tricky thing because it’s like, is this due to the actual dosage just being higher than we can get through food? I can see that being the issue. And my kind of perspective is in situations where there are not clear benefits.
I think it makes sense to avoid having high dose antioxidants around the time of training. Clear benefits to me are, for example, let’s use that beetroot juice as an example, being like somebody’s running a 5K time trial and they really want to perform their best. Having beetroot juice before that makes sense to me. I don’t care that it’s high dose antioxidants, like it’s like, I’ll give them that. That competition thing that I talked about, the tart cherry juice, about being less sore, that makes sense to me.
I just wouldn’t be doing it year round, particularly if we don’t have any clear benefits, but like I wouldn’t be overly scared of it. And then jumping that back to like, cause we do seem to have a bit more evidence on the endurance stuff with bigger impairments being seen or more consistent impairments being seen. From the hypertrophy perspective, it’s likely, it doesn’t matter much. Like it just likely doesn’t matter much at all. When I was seeing this stuff being discussed on forums many years ago, there would be people who like, I know an IFBB pro who has vitamin C right before training. It just doesn’t matter, right? Like it just doesn’t matter that much. So I wouldn’t stress about this, but I would still take the claim of I wouldn’t go out of my way to have high dose antioxidants around the time of training just to be a little bit cautious in case this actually does matter. Cause the mechanisms do seem to make sense. There is a little bit of research on this topic, but I also wouldn’t stress about it either.
Leah:
This has been episode 151 of the Ideal Nutrition Podcast. If you haven’t yet left a rating review, you know we’d always greatly appreciate it, but otherwise thanks for tuning in.