Episode 151 – Is Having Antioxidants Around Training a Bad Idea?

Key Topics Covered

Antioxidant containing foods.

  • Traditionally, antioxidants are seen as beneficial. 
  • And there are some promising links with training, such as reductions in DOMs.
  • But there are theoretical reasons why they could have downsides, for both endurance and hypertrophy. 
  • The simple logic is that while we normally view oxidative stress and inflammation as negatives, they can also be a stimulus for adaptation
  • So theoretically, somebody could be less sore but make less progress.
  • But this is a very complex topic for a multitude of reasons.
  • Including what kind of dose are we talking about? And what kinds of antioxidants are we talking about?
    • If you have seen people talking about carotenoids, polyphenols, flavonoids, flavanols or flavones, technically all of those are antioxidants. There are also over 4,000 known flavonoids too. So you can see how big this space is.

Delayed Onset Muscle Soreness (DOMS)

Delayed Onset Muscle Soreness on leg muscle.

  • The research on reducing muscle soreness is really positive.
  • Vitamin C and vitamin E have mixed but slightly favorable research for this.
  • Supplements that are really high in polyphenols have been much more positive – including tart cherry juice as an example.
  • Pomegranate juice and watermelon juice have also had similar outcomes that are likely related to antioxidants too.

Other Positives

  • Other high-antioxidant strategies have been linked with acute benefits.
Endurance athletes running on beach.

Beetroot Juice

  • Example 1: Beetroot juice 2-3 hours before a session improves both endurance performance and also likely high-rep gym work. This is due to nitrates, but beetroot juice is also very high in polyphenols.
    • But this is typically more so recommended in the lead-up to an event and on the day of an event instead of habitual intake – this is where we are often no longer need to make physiological adaptations.

New Zealand Blackcurrant Extract

  • Example 2: New Zealand blackcurrant extract which is really high in anthocyanins, has been proposed to help sports performance due to reducing oxidative stress, inflammation and improved vasodilation.
    • This has led to 1-2% improvements in race times on average when used daily leading up to events. 
    • Again in the lead-up to, not necessarily habitual intake around a bunch of training sessions.

Training Adaptations

  • The mechanisms make it seem like it should be detrimental, but what does the research show?
  • Most research is on endurance athletes. Vitamin C and E both have decent amounts of research, but more research would be good.
  • Of the 9 studies we have on vitamin C in this space fitting the criteria of using dosages >1g per day and taking it for over a week, 4 showed impairments in performance over time vs placebo, and another 4 were not statistically significant but showed small impairments vs placebo. 1 was positive.
  • If interested, you can find those studies by going to a 2023 review titled ‘Antioxidants and Sports Performance’, although they word it slightly differently because they included studies that had vitamin C for <1 week.
  • Another one involving vitamin C and E at decent dosages for 11 weeks had smaller improvements in cycling performance than placebo too.
  • The interpretation from all of this is that high-dose antioxidants in the form of supplements should probably be cautioned against near training when the goal is adaptation.

Lifting Specific Research

Man squatting with barbell.

  • Unfortunately, there is not as much research in this area.
  • Similarly to endurance, research looking at mechanisms has found that antioxidants can inhibit anabolic pathways.
  • A 2020 systematic review involving 9 studies on vitamins E and C on resistance training found almost no difference in muscle growth, but it was actually slightly in favor of those vitamins instead of placebo.
  • Stronger by Science did a good breakdown highlighting flaws in this such as how 3 of those studies were actually one experiment that had the data used in 3 different papers. Then they highlighted the accuracy of measuring with tools like DEXA could account for any differences evident, as they were quite small. And when accounting for these variables, this wouldn’t be interpreted as favorable findings.

Additional Research

  • Another review looking at antioxidants and resistance training demonstrated that on average research has found small impairments. They also noted these impairments were of larger magnitude in younger lifters than older lifters, and if this were to be consistent with additional research, the logic would be based on older lifters having higher baseline oxidative stress.
  • It also appears that some antioxidants are more likely to be relevant for this than others
    • For example, these authors appear more concerned about vitamins C and E than they do about polyphenols, flavanols and anthocyanins.

Our Interpretation

  • I see no issue with trying to get as many antioxidants in through whole foods as you can. I’ve never seen anything to indicate that it would be an issue to do that.
  • I can see the logic as to why getting abnormal amounts from supplements could be a concern here. And in situations where there are not clear benefits, I think it makes sense to avoid having high-dose antioxidants near training. 
  • There are certainly exceptions to this though. For example I like using beetroot juice for certain athletes at certain times. Then it comes down to semantics about what is a supplement e.g. a 70ml concentrated shot of beetroot juice is like 1kg of whole beetroot. But we see clear benefits for performance, so I will use that short-term leading up to events. I don’t tend to use that long-term though.
  • Another point though is particularly for hypertrophy, this likely doesn’t matter much. I wouldn’t stress about it. 

Relevant Blogs / Resources

Relevant Research:

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