Goldilocks, Exercise Training and Vitamins C and E
In competitive sports, athletes are always looking for the advantage. Ask Alex Rodriguez, New York Yankees baseball superstar. Nutrition is important but nutrients are not performance-enhancing products. They are essential for cell metabolism. Just like sleep is important for optimal performance.
For top performance (physical and mental), bodies need to be adequately nourished, rested, and physically trained. Without measuring nutrient status, it is difficult to know if you are eating too little, just enough, or more than enough of a nutrient. Just imagine the dietary algorithm we are solving when we try to balance our intake of essential nutrients, energy sources (carbohydrates, fats, proteins) to fuel cells, long-chain polyunsaturated fatty acids (PUFAs) to maintain cellular membranes, and essential amino acids to build proteins. Because of the metabolic complexity, our bodies must adapt continuously.
Paulsen et al (2013) wanted to know if supplemental vitamins C and E would affect endurance training adaptation (vs placebo). During the study in 54 male and females, exercise performance increased in both treatment groups. Previously untrained individuals improved more than those exercising regularly before the study began. Not surprising. Supplementation with 1000mg vitamin C and 235 mg vitamin E daily did not affect physiological performance, i.e. VO2max or performance in a 20 meter shuttle test, versus placebo. Examination of training diary and heart rate data found no differences in training intensity or perceived exertion between placebo vs supplemented groups. Significant treatment differences in some, but not all, biochemical/molecular markers of blood and muscle biopsies were reported. This finding is being interpreted in the media as if supplements blunt or negatively impact endurance training.
The story isn’t this simple. First, as acknowledged by Paulsen and colleagues, Yfanti et al (2010) measured different biochemical markers and found vitamin C and E supplementation did not alter endurance training adaptation. The reality is that hundreds of biochemical/molecular markers are influenced by external factors: nutrition, genetics, and environment (Menni et al, 2013). Runners experience profound changes with 75 metabolites increasing more than 2X following 3 days of 2.5h runs on a treadmill at ~70% VO2max (Nieman et al, 2013). When so many markers can change, one needs to be skeptical of articles reporting significant changes in one or two (Lane, 2013).
Studies such as this one by Paulsen and colleagues are important to understand human body adaptations to exercise. Still, we need to keep perspective. These are studies elucidating the relationship between nutritional supplementation, exercise-induced adaptation, and biochemical/molecular markers. As an athlete (or someone who wishes to think they are athletic), the physiologically relevant findings are that supplement use didn’t affect physical performance. Since supplementing vitamins C and E didn’t affect training outcomes (Yfanti et al, 2010; Paulsen et al, 2014), it seems circumspect when headlines suggest otherwise.
Like Goldilocks, we want to have ‘just the right’ amount. Nutrient recommendations are established by age and gender to meet the needs of almost everyone (97.5%). Let this be your guide.
Paulsen G, Cumming KT, Holden G, Hallen J, Ronnestad BR, Sveen O, Skaug A, Paur I, Bastani NE, Ostgaard HN, Buer C, Midttun M, Freuchen F, Wiig H, Ulseth ET, Garthe I, Blomhoff R, Benestad HB, Raastad T. Vitamin C and E supplementation hampers cellular adaptation to endurance training in humans: a double-blind randomized controlled trial. 2014 J Physiol doi: 10.1113/jphysiol.2013.267419
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Yfanti C, Akerstrom T, Nielsen S, Nielsen AR, Mounier R, Mortensen OH, Lykkesfeldt J, Rose AJ, Fischer CP, Pedersen BK. Antioxidant supplementation does not alter endurance training adaptation. 2010. Med Sci Sports Exerc doi: 10.1249/mss.0b013e3181cd76be
Lane DM. The problem of too many statistical tests. Subgroup analyses in a study comparing the effectiveness of online and live lectures. 2013 Numeracy doi: 10.5038/1936-46220.127.116.11
Nieman DC, Shanely RA, Gillitt ND, Pappan KL, Lila MA. Serum metabolic signatures induced by a three-day intensified exercise period persist after 14h of recovery in runners. 2013 J Proteome Res doi: 10.1021/pr400717j
Menni C, Zhai G, MacGregor A, Prehn C, Romisch-Margl W, Suhre K, Adamski J, Cassidy A, Illig T, Spector TD, Valdes AM. Targeted metabolomics profiles are strongly correlated with nutritional patterns in women. 2013 Metabolomics doi: 10.1007/s11306-012-0469-6