Vitamins–you can’t get too many of those, right? Well, actually you can. For some vitamins, your body can eliminate the excess. This is true of water-soluble vitamins. Fat-soluble vitamins that dissolve only in fatty solutions are not as easy to get rid of. If you take these vitamins in high-dose supplement form, they can build up in your body, sometimes to toxic levels. Fat-soluble vitamins include vitamins A, D, E, and K. But if you’re trying to build muscle, there may be another concern. A new study shows that supplementing with antioxidant vitamins may reduce the hypertrophy gains you get from your weight-training workouts.
Antioxidant and Muscle Gains: What New Research Shows
A new study in the International Journal of Exercise Science calls into question the practice of taking antioxidant vitamins in supplement form. The fact that this was a double-blinded, randomized, controlled study adds credibility to the results, as it’s the most high-quality study there is. The participants were 33 young, healthy women.
For the study, participants were divided into three groups. One group supplemented with antioxidant vitamins (vitamins C 100 grams/ day and E 400 IU/day), a second supplemented with a placebo, and a third did neither. The last group served as a control group. The first two groups took part in a 10-week strength training program that emphasized lower body strength exercises and compound exercises, such as deadlifts, chest press, rows, and lunges. They trained twice per week and did each set to momentary failure. They adjusted the resistance with each set to ensure the participants could complete the designated number of reps.
At the end of the 10 weeks, the researchers looked at changes in fat mass and fat-free mass in the three groups. The only significant changes in fat-free mass and fat mass were in the placebo group. In this group, participants lost body fat and gained muscle. The group who took the antioxidant vitamins did not.
What can we conclude? Although vitamin C and vitamin E play an essential role in overall health, taking supplemental doses may interfere with muscle gains. One downside to the study is that it only included young, healthy females. Interestingly, another study in elderly people found that supplementing with similar quantities of vitamin C and vitamin E was associated with greater gains in fat-free mass after six months of strength training. However, this study had some limitations.
Another study in the elderly found that gains in muscle mass were greater in those who took a placebo as opposed to antioxidant supplements (5% vs 2% gains, supporting the idea that antioxidant vitamins may interfere with muscle gains in response to strength training.
Why Might Antioxidant Supplements Reduce Strength Gains?
According to recent evidence, the creation of reactive oxygen species, the same entities that antioxidants destroy, is a stimulus for muscle hypertrophy. These reactive oxygen species turn on pathways that lead to muscle hypertrophy. Exercise itself creates these reactive oxygen species and when antioxidants destroy them, the body doesn’t turn on pathways involved in muscle protein synthesis.
Some people take antioxidant vitamins in hopes of reducing the aging effects of oxidative stress. Free radicals formed with oxidative stress can damage cells and their components. One theory is that oxidative stress plays a role in aging and in age-related health problems, like cancer. While we certainly don’t want large amounts of oxidative stress, the oxidative stress induced by exercise is short-lived and may be necessary for some exercise adaptations to take place. There is even evidence that they interfere with positive adaptations to endurance exercise.
One reason people who exercise take antioxidant vitamin supplements is the belief that they reduce muscle soreness and speed up recovery from exercise. There is also the belief that antioxidants improve muscle performance. However, these potential benefits are not supported by science. In fact, there’s research showing that increased reactive oxygen species during exercise helps with the repair of muscle cells after injury or after a tough workout. When you take in large amounts of antioxidants, you may hinder this repair. In turn, this can reduce the muscle’s ability to generate force.
What This Means
At the very least, avoid consuming large amounts of antioxidants prior to a workout. It is likely that your muscle cells need some exposure to reactive oxygen species to maximize repair and muscle hypertrophy. Also, get your antioxidants through diet rather than by taking them in supplement form. Most supplements contain larger quantities than your body needs. This doesn’t mean you shouldn’t eat antioxidant-rich fruits and vegetables. Foods contain antioxidants in a more balanced form than what you get from a supplement. Even then, it might not be a good idea to drink a big glass of antioxidant-rich fruit juice before a workout as juice would be a more concentrated source of antioxidants. If you regularly eat fruits and vegetables, you’re probably meeting your body’s requirement for vitamin C, and, keep in mind, there are potential harms to too much vitamin C. For one, large quantities of vitamin C increase the risk of kidney stones. What about vitamin E? You should be able to get enough vitamin E naturally through diet if you consume nuts and seeds. Most people who consume processed foods also get enough vitamin E as it’s abundant in common cooking oils like corn oil and soybean oil.
The Bottom Line
Antioxidant vitamins won’t give you an edge with weight training, and they may even be detrimental. Maximize the quality of your diet by choosing nutrient-rich foods that are naturally high in vitamins, minerals, and phytonutrients that support health and muscle gains. The solution to getting your fittest doesn’t lie with a bottle of supplements but a balanced diet and consistent training.
· Int J Exerc Sci. 2019; 12(2): 287–296.
· Appl Physiol Nutr Metab. 2018 Aug;43(8):775-781. doi: 10.1139/apnm-2017-0866. Epub 2018 Jun 25.
· Am. J. Clin. Nutr. 87:142-149.
· Examine.com. “Why you shouldn’t be always taking antioxidants, especially if you want to build muscle”