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Vitamin C in large doses slows muscle growth by quenching not just bad ROS, but helpful ROS as well. ROS is essential to insulin benefits from exercise.
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Oral administration of vitamin C decreases muscle mitochondrial biogenesis and hampers training-induced adaptations in endurance performance
BY KAMAL PATEL, MPH, MBA, PHD
When budgeting out your supplement supply for the next phase of your training, you probably put whey and creatine high on the list but do you leave enough room for key antioxidants?
Out of all categories of supplements, antioxidants are one type that is highly underrated – and misused. If you can quench those evil free radicals in order to live longer and feel better, while also aiding recovery and reducing soreness, why not load up with antioxidants? However, before you start filling your online cart with antis, it’s important to note that proper usage is key. You can’t and shouldn’t avoid them but you also shouldn’t be so gung ho. Using antioxidant supplements the wrong way could actually hinder your progress, because sometimes oxidation is actually good (gasp). And sometimes antioxidants can even turn to the dark side and become pro-oxidants.
FAULTY FINDINGS
In 1998, news headlines warned against the dangers of vitamin C after the publication of a controversial study in the prestigious journal Nature. The study showed that some DNA was oxidized by vitamin C, which isn’t good, but some DNA was also protected from oxidation by vitamin C. Turns out the protection was around ten times greater in magnitude -- a fact that was conveniently left out of the paper. The paper was attacked and the author pretty much reversed his conclusion. So outside of that popular but flawed study, what does the evidence say about antioxidants turning bad specifically for exercise?
Well...results are somewhat mixed. The few studies directly testing antioxidants for muscle growth after a weightlifting routine fail to show a benefit. But there are many different markers of muscle damage that you can measure after a workout, so there are some studies showing benefits of antioxidants. These may just be temporary benefits though, not supporting long-term muscle growth. Bear with us…there are a lot of interesting competing factors.
You definitely don’t want to overdo it. There have been a few trials showing that post-workout antioxidants, typically vitamin C and vitamin E at larger doses, can blunt some of the positive effects from exercise. For example, exercise normally improves insulin resistance but that positive effect disappears when you take vitamin C and vitamin E after the workout. Why is that?
It turns out that reactive oxygen species (ROS) are not universally bad, and one of their important functions is to signal the body to increase protein synthesis as part of the mTOR pathway. Vitamin C in extremely large doses inhibits muscle growth by quenching not just bad ROS, but helpful ROS as well. And ROS is also essential to insulin benefits from exercise.
It’s also important to realize that while we get antioxidants through foods and supplements, we have an even more powerful antioxidant system that our own bodies provide. And some evidence has shown that post-exercise antioxidants can curb our body’s natural antioxidant response to exercise.
Perhaps more importantly, taking too many antioxidants may be harmful for longevity. Researchers previously thought that ROS were largely responsible for shortened lifespans but current thinking indicates that ROS may actually be important for increasing lifespan. The reason is a concept called “mitohormesis”, with “hormesis” referring to your body’s positive adaptation to stressors (like growing muscle after the stress of weightlifting or altitude training improving cardio capacity), and “mito” referring to the mitochondria where these adaptations arise from.
Essentially, small amounts of stress within your cells caused by ROS can lead to improved stress resistance naturally created by your body. And that stress resistance could play an important role in living a long and healthy life.
THE BOTTOM LINE
All that being said, don’t go to the extreme and avoid antioxidant vitamins altogether. Vitamin C is critical to collagen formation, which is something that comes up a lot when you’re taxing your joints lifting heavy weights. And antioxidants are overall quite beneficial for health, just not necessarily when mega-dosed right after your workout.
Remember that a healthy diet should incorporate a variety of antioxidant-rich nutrients, as antioxidants often work together with one another. So as usual, focus on getting a balance of nutrients from your diet, and always be careful before going heavy any nutrient.
When budgeting out your supplement supply for the next phase of your training, you probably put whey and creatine high on the list but do you leave enough room for key antioxidants?
Out of all categories of supplements, antioxidants are one type that is highly underrated – and misused. If you can quench those evil free radicals in order to live longer and feel better, while also aiding recovery and reducing soreness, why not load up with antioxidants? However, before you start filling your online cart with antis, it’s important to note that proper usage is key. You can’t and shouldn’t avoid them but you also shouldn’t be so gung ho. Using antioxidant supplements the wrong way could actually hinder your progress, because sometimes oxidation is actually good (gasp). And sometimes antioxidants can even turn to the dark side and become pro-oxidants.
FAULTY FINDINGS
In 1998, news headlines warned against the dangers of vitamin C after the publication of a controversial study in the prestigious journal Nature. The study showed that some DNA was oxidized by vitamin C, which isn’t good, but some DNA was also protected from oxidation by vitamin C. Turns out the protection was around ten times greater in magnitude -- a fact that was conveniently left out of the paper. The paper was attacked and the author pretty much reversed his conclusion. So outside of that popular but flawed study, what does the evidence say about antioxidants turning bad specifically for exercise?
Well...results are somewhat mixed. The few studies directly testing antioxidants for muscle growth after a weightlifting routine fail to show a benefit. But there are many different markers of muscle damage that you can measure after a workout, so there are some studies showing benefits of antioxidants. These may just be temporary benefits though, not supporting long-term muscle growth. Bear with us…there are a lot of interesting competing factors.
You definitely don’t want to overdo it. There have been a few trials showing that post-workout antioxidants, typically vitamin C and vitamin E at larger doses, can blunt some of the positive effects from exercise. For example, exercise normally improves insulin resistance but that positive effect disappears when you take vitamin C and vitamin E after the workout. Why is that?
It turns out that reactive oxygen species (ROS) are not universally bad, and one of their important functions is to signal the body to increase protein synthesis as part of the mTOR pathway. Vitamin C in extremely large doses inhibits muscle growth by quenching not just bad ROS, but helpful ROS as well. And ROS is also essential to insulin benefits from exercise.
It’s also important to realize that while we get antioxidants through foods and supplements, we have an even more powerful antioxidant system that our own bodies provide. And some evidence has shown that post-exercise antioxidants can curb our body’s natural antioxidant response to exercise.
Perhaps more importantly, taking too many antioxidants may be harmful for longevity. Researchers previously thought that ROS were largely responsible for shortened lifespans but current thinking indicates that ROS may actually be important for increasing lifespan. The reason is a concept called “mitohormesis”, with “hormesis” referring to your body’s positive adaptation to stressors (like growing muscle after the stress of weightlifting or altitude training improving cardio capacity), and “mito” referring to the mitochondria where these adaptations arise from.
Essentially, small amounts of stress within your cells caused by ROS can lead to improved stress resistance naturally created by your body. And that stress resistance could play an important role in living a long and healthy life.
THE BOTTOM LINE
All that being said, don’t go to the extreme and avoid antioxidant vitamins altogether. Vitamin C is critical to collagen formation, which is something that comes up a lot when you’re taxing your joints lifting heavy weights. And antioxidants are overall quite beneficial for health, just not necessarily when mega-dosed right after your workout.
Remember that a healthy diet should incorporate a variety of antioxidant-rich nutrients, as antioxidants often work together with one another. So as usual, focus on getting a balance of nutrients from your diet, and always be careful before going heavy any nutrient.
Oral administration of vitamin C decreases muscle mitochondrial biogenesis and hampers training-induced adaptations in endurance performance
Written By The American Society for Clinical Nutrition
Background: Exercise practitioners often take vitamin C supplements because intense muscular contractile activity can result in oxidative stress, as indicated by altered muscle and blood glutathione concentrations and increases in protein, DNA, and lipid peroxidation. There is, however, considerable debate regarding the beneficial health effects of vitamin C supplementation.
Objective: This study was designed to study the effect of vitamin C on training efficiency in rats and in humans.
Design: The human study was double-blind and randomized. Fourteen men (27–36 y old) were trained for 8 wk. Five of the men were supplemented daily with an oral dose of 1 g vitamin C. In the animal study, 24 male Wistar rats were exercised under 2 different protocols for 3 and 6 wk. Twelve of the rats were treated with a daily dose of vitamin C (0.24 mg/cm2 body surface area).
Results: The administration of vitamin C significantly (P = 0.014) hampered endurance capacity. The adverse effects of vitamin C may result from its capacity to reduce the exercise-induced expression of key transcription factors involved in mitochondrial biogenesis. These factors are peroxisome proliferator–activated receptor co-activator 1, nuclear respiratory factor 1, and mitochondrial transcription factor A. Vitamin C also prevented the exercise-induced expression of cytochrome C (a marker of mitochondrial content) and of the antioxidant enzymes superoxide dismutase and glutathione peroxidase.
Conclusion: Vitamin C supplementation decreases training efficiency because it prevents some cellular adaptations to exercise.
Background: Exercise practitioners often take vitamin C supplements because intense muscular contractile activity can result in oxidative stress, as indicated by altered muscle and blood glutathione concentrations and increases in protein, DNA, and lipid peroxidation. There is, however, considerable debate regarding the beneficial health effects of vitamin C supplementation.
Objective: This study was designed to study the effect of vitamin C on training efficiency in rats and in humans.
Design: The human study was double-blind and randomized. Fourteen men (27–36 y old) were trained for 8 wk. Five of the men were supplemented daily with an oral dose of 1 g vitamin C. In the animal study, 24 male Wistar rats were exercised under 2 different protocols for 3 and 6 wk. Twelve of the rats were treated with a daily dose of vitamin C (0.24 mg/cm2 body surface area).
Results: The administration of vitamin C significantly (P = 0.014) hampered endurance capacity. The adverse effects of vitamin C may result from its capacity to reduce the exercise-induced expression of key transcription factors involved in mitochondrial biogenesis. These factors are peroxisome proliferator–activated receptor co-activator 1, nuclear respiratory factor 1, and mitochondrial transcription factor A. Vitamin C also prevented the exercise-induced expression of cytochrome C (a marker of mitochondrial content) and of the antioxidant enzymes superoxide dismutase and glutathione peroxidase.
Conclusion: Vitamin C supplementation decreases training efficiency because it prevents some cellular adaptations to exercise.
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