Nutritional Supplementation in Wrestlers
The following does not constitute medical advice, professional diagnosis, treatment, or services in any way, shape or form. If you have questions or concerns about your health, consult with your doctor for individualized recommendations.
LET'S COMBAT BRO SCIENCE TOGETHER, SHALL WE?
I recently wrote a paper reviewing what is known about nutritional supplementation in wrestlers, and I thought it might be of interest to you, so I put this post together to share some of the findings. I have tried to translate everything from total nerd language to more approachable, general explanations, including explanations of some basic physiology & biochem concepts because I think this kind of literacy is important.
Keep in mind that supplementation was evaluated for its effect on wrestling performance, and not in terms of other measures, such as prevention of any kind of disease. So, for instance, just because a study below may determine that a particular nutraceutical may not affect wrestling performance, this does not mean that it may not have beneficial (or detrimental!) effects in other areas of one's life.
BEFORE WE GET STARTED (PUT YOUR RESEARCHER HAT ON!)
- Wrestling involves abrupt, high-intensity, repeated sessions of supra-maximal and sub-maximal work, particularly anaerobic upper body activity. As endurance and power are major concerns of the combat athlete, studies in wrestlers tend to focus on measuring an intervention's effect on these elements. Wrestling matches are often simulated in these studies by UBISP: Upper Body Intermittent Sprint Performance, which is a standardized way of measuring upper body anaerobic activity via arm crank testing on a machine. UBISP has been compared with actual wrestling competition to ensure that it proximates live wrestling.
- I did not include studies that looked at supplementation in "athletes" in general; I reviewed only those studies that were carried out specifically in wrestlers. Athletic activity comes in many forms, some of which may or may not be relevant to the wrestler. Therefore, to make the review as applicable as possible to wrestlers, I was very specific and only reviewed studies done in wrestlers. This means that there is likely applicable information out there for athletes in general that has not been taken into account.
- The majority of research available involves elite athletes. In academic studies, an "elite athlete" is typically considered as someone who is engaged in a sport at the varsity or professional level. This means that findings may have questionable applicability to the recreational athlete. Level of athletic training does affect physiology, therefore we can't say that findings in elite athletes can definitively be applied to the general population. That said, it has been argued that the trained nature of participants in these studies may actually improve the validity of outcomes, as we would expect less variability throughout performance testing and a minimization of the effect of supplementation(1,3). This is to say that we may reasonably expect an equal or greater effect of supplementation in an untrained or recreational athlete, though we would need to examine this to be sure.
- Sex differences affect supplementation. It has now been well-established that conclusions from studies using only male participants cannot necessarily be applied to female populations. Differences in exercise physiology are largely attributable to 17-β-estradiol (estrogen), which confers a preferential usage of fat oxidation. Also, women have a higher area of type I ("slow-twitch") muscle fibres compared to men(19,20). For instance, females do not show reductions in protein breakdown and show less of an increase in lean body mass following acute creatine loading as compared to males(19). Bottom line: ladies, be wary of conclusions drawn from studies done in males regarding exercise physiology and supplementation.
- The majority of research available involves fairly small participant numbers. Numbers matter! Because most studies examining wrestlers are done at universities, there are very limited numbers of participants, depending on the team. Most of the studies included involve between 5-20 wrestlers, so there is the possibility that such small numbers may provide misleading results.
For example, let's say 2 out of 5 participants exhibit some really drastic outcome as a result of supplementation with zinc. Our results would then be that 40% (2/5) of participants demonstrated a particular outcome after supplementation. However, what if there was something about these two particular individuals that predisposed them to respond to zinc supplementation in that way, or for whatever reason they are some kind of outlier. If we only take our total of five people into account, it's going to look like 2 out of 5 is a really big deal, and then we may be inclined to spread the word that zinc supplementation confers amazing results. Well, what if we expanded the number of people we were including in the study to 100, and then found that it was actually only these 2 people again who showed an effect with supplementation. Suddenly our percentage for efficacy drops down to 2% (2/100). This is why it can be problematic to have such small participant numbers. It can be hard to discern the actual effect of your intervention.
- Biochemical markers and performance outcomes are not the same thing!
Lots of studies will measure how supplementation with a nutraceutical alters the levels of various biological parameters, but whether or not this actually translates into a performance outcome is an entirely different question. It has been shown that supplementation with zinc in wrestlers increased the activity of a particular enzyme, but researchers did not perform any tests to determine whether or not this actually affected wrestlers' athletic ability. So who is to say that an increase in activity of this particular enzyme provides you with any kind of athletic benefit? We can't.
- Geography makes a surprisingly large difference when it comes to studies in nutrition. Keep in mind the global variability in diet. You may see a significant benefit with fish oil supplementation in a North American population, and less of an effect in a Japanese population, for instance. Why is that? Well, the Japanese diet tends to include much more seafood than the American or Canadian diet. If the North American population is generally lacking in omega-3s, then you would expect supplementation to provide some kind of difference in terms of biochemical parameters, whereas if a Japanese population already has adequate intake, you would be less likely to see the same results.
Creatine is known to increase athletic performance and delay the onset of muscular fatigue during short-term, high-intensity bouts of exercise(4) and to improve recovery(5). Phosphocreatine essentially acts as an energy buffer during physical exertion, regenerating ATP from ADP via the creatine kinase reaction(4).
What is ATP and Why Should I Care?
Think of ATP like the energy currency of the cell. It stands for "adenosine triphosphate", and basically, whenever you expend energy in your body (which is pretty much always), you need to pay! You have a bunch of ATP in your body (think of it like money in the bank). During muscle contraction, you use a bunch of ATP and "pay" with one of the phosphates from each ATP molecule that you're using. What do you get when you take a phosphate away from adenosine triphosphate (ATP)? Adenosine diphosphate (ADP)!
Okay, so you have used an ATP during muscle contraction, and now you have a leftover ADP. You need to turn that ADP back into ATP for your muscle to keep working (just like you need to earn more money to pay for whatever you need to pay for), so you better find another phosphate somewhere! Typically, your ATP is regenerated by mitochondria, which are guys in the cell known to be energy factories. When the rate of ATP regeneration by mitochondria is not enough to keep up, phosphocreatine (creatine + a phosphate group it picked up earlier) is used to regenerate ATP from ADP.
So... you guessed it! Creatine is helpful as a second-line energy system, essentially. And, to be clear, you already have some creatine in your body, because you can get it through diet.
Does It Actually Work?
- When wrestlers on the Turkish national team ingested 20g a day of oral creatine for five days, an increase in average power of 12.3% and increase in peak power of 17% were shown(4). The placebo group experienced no significant change between pre- and post-test average of peak anaerobic power.
- One study(6) looked at creatine plus carbohydrate ingestion in wrestlers (versus carbohydrate alone) to see if it would help stimulate the recoup of physical performance in wrestlers looking to restore mass and function after a weight cut prior to competition. The combination of creatine plus carbohydrate did not appear to accelerate the restoration of body mass, but they did demonstrate a 19.2% increase in maximal work, whereas no change was evident in the group that relied solely on glucose for recovery.
- While the safety of creatine supplementation for most individuals has been well-established, it has been questioned whether or not it may pose a risk of cytotoxicity, as creatine can be metabolized to formaldehyde. When urinary formaldehyde levels in wrestlers taking creatine were examined, it was determined that the addition of whole-body resistance training to creatine supplementation lowered the rate of excretion of formaldehyde by approximately 17.7%(5). Researchers concluded that 0.3 g / kg of body weight per day of creatine consumption (approximately 20 g / day for the average person) may be less toxic when combined with training.
Caffeine is included as an ingredient in many pre-workout supplements, which as a category are intended to increase energy, focus, and endurance for the immediate training session.
Consuming 5 mg of caffeine per kg of body weight before upper body intermittent sprint performance (UBISP) testing – a test designed to mimic consecutive wrestling matches – actually decreased peak power attained during testing, and had no significant effect on average (mean) power(7). Researchers concluded that acute caffeine ingestion has a partially detrimental effect on upper body intermittent sprint performance in trained wrestlers.
How much caffeine is 5mg/kg of body weight? For a 150-lb. guy, that is 340g of caffeine. In a typical cup of brewed coffee, there is about 100-200mg of caffeine. Most of the pre-workouts that I've seen with caffeine include about 150-400mg of caffeine, so doses this high are not uncommon.
What else is in a lot of pre-workouts? Arginine. As a precursor to the potent vasodilator nitric oxide, it is typically claimed that supplementation with arginine may augment blood perfusion in active muscle. Arginine supplementation was examined in wrestlers to examine its potential role in muscle recovery and preventing muscular fatigue(8), as there is little time between matches for rest and recovery. The actual evidence for arginine conferring an ergogenic benefit is mixed, and appraisal of the literature is complicated since studies often examine arginine in combination with other nutraceuticals.
Time to exhaustion was increased by 5.8% in wrestlers taking a single dose of 1.5g / 10 kg body weight of arginine(8). However, the test used to determine this was a cycle ergometer; basically a stationary bicycle where you pedal against a load to measure anaerobic capacity. With supplementation, mean time to exhaustion increased 73.8 seconds above and beyond the placebo group, who pedalled for about 21 minutes until they reached exhaustion. Now, in terms of athletic performance during a wrestling match, an increase in time to exhaustion of over a minute is significant, but I'll leave it up to you to think about whether or not cycle ergometry measures are applicable to a wrestling match.
Another study (9) looked at the effect of arginine and branched chain amino acids (BCAAs) for their combined effect on performance in wrestlers in simulated matches. Results indicated that arginine and BCAAs did not confer a benefit to peak or average power.
Studies in trained wrestlers have failed to show any significant difference in peak power, mean power, or total work achieved in simulated wrestling matches vs placebo with supplementation of sodium citrate, sodium chloride, or sodium bicarbonate(1,3). These preparations are intended to buffer against exercise-induced acidosis in athletes.
Several explanations have been advanced in account of the findings. It has been proposed that the skeletal muscle of athletes engaging in sports with significant anaerobic requirement tend to demonstrate an adaptation of high intracellular buffering capacity, and therefore may minimize the observed effect of supplementation(3). Some question whether a wrestling match is of long enough duration to elicit acidosis in the athlete, suggesting that brief bouts of anaerobic activity may be fully sustained by the use of phosphocreatine(1).
Sodium citrate supplementation was also investigated for its effect on weight recovery after cutting prior to competition(10). Wrestlers ingested either 600mg of sodium citrate per kg of body weight or placebo, and completed an UBISP test prior to and post weight cut. All wrestlers maintained the same diet and training regimen as they would prior to actual competition. While the sodium citrate group did experience a greater increase in body mass, there was no difference in terms of performance.
Chronic β-alanine supplementation boosts the synthesis of intramuscular carnosine which is purported to be an intracellular pH buffer(11). After eight weeks of supplementation with 4g / day of β-alanine, wrestlers achieved a 1.6 second mean decrease on their 300-yd shuttle time (a test of anaerobic endurance), versus a 1.3 second decrease for placebo. Wrestlers in the supplementation group also increased their lean mass by 1.1lb, whereas the placebo group lost 0.98lbs. The question to ask here is whether or not eight weeks of supplementation is worthwhile to the athlete to confer such a minuscule benefit (my opinion: No).
Human cells build three types of superoxide dismutase (SOD) enzymes, one of which includes copper and zinc. SOD protects against free radical formation, to which muscular exercise contributes(13). Oxidative stress was measured in wrestlers taking 5mg / kg of body weight daily of a zinc sulphate preparation for eight weeks(14). Those supplementing with zinc demonstrated the highest SOD activities. Researchers concluded that supplementation with zinc may beneficially contribute to athletic performance, but my issue with this is that chemical markers are only one part of the picture. No performance measures were assessed, therefore whether or not the higher levels of SOD would confer a meaningful outcome for the athlete is debatable.
It is known that high-intensity training can induce bronchoconstriction, and individuals engaged in demanding athletic training are at increased susceptibility of upper respiratory tract infection for 1-2 weeks post-training(15). The effect of omega-3 supplementation on pulmonary variables (to assess lung capacity) was examined in young male, non-smoking wrestlers. These measures were significantly greater in the supplementation group compared to baseline and placebo. If you know anything about respiratory physiology, you may be interested to know that the likely mechanism for such change was an increase in pulmonary surfactant production. If you don't care about pulmonary physiology, carry on. :)
No performance parameters were assessed, so it is not possible to ascertain what effect omega-3 supplementation may have on wrestling performance, however, my opinion is that optimized pulmonary capacity may reasonably be expected to increase athletic ability.
Chromium is an essential trace element best known for its role in enhancing the effects of insulin(16). College wrestlers engaged in a strength and conditioning program were put on 14 weeks of chromium picolinate, 200mcg / day versus placebo(17). No differences between groups were observed in terms of body composition and aerobic power, which increased significantly in all groups independent of supplementation (i.e., the increase in power was likely attributable to the strength and conditioning program, and not the chromium).
SO, WHAT DOES THIS ALL MEAN?
Many of the studies have demonstrated biochemical changes with supplementation, but they rarely actually translate into a performance benefit for the athlete, or the benefit is so small that supplementation may be moot.
Currently, as we can see from the available literature with regard to nutritional supplementation in wrestlers, creatine is the only supplement that has a clearly marked benefit for the athlete, significantly increasing performance capacity with an established safety record.
Early research seems to suggest that supplementation with arginine, β-alanine, and omega-3s may potentially offer some benefit to the combat athlete. Supplements clearly showing no benefit to the combat athlete include caffeine, various sodium buffers, zinc, and chromium.
- Aschenbach W, Ocel J, Craft L, et al. Effect of oral sodium loading on a high-intensity arm ergometry in college wrestlers. Med Sci Sports Exerc. 2000;32:669-675.
- Lazic S, Dikic N, Radivojevic N, et al. Dietary supplements and medications in elite sport—polypharmacy or real need? Stand J Med Sci Sports. 2011 Apr;21(2):260-7.
- Aedma M, Timpmann S, Ööpik V. Dietary sodium citrate supplementation does not improve upper-body anaerobic performance in trained wrestlers in simulated competition-day conditions. Eur J Appl Physiol. 2015;115:387-396.
- Koçak S, Karli Ü. Effects of high dose oral creatine supplementation on anaerobic capacity of elite wrestlers. J Sports Med Phys Fitness. 2003;43:488-92.
- Nasseri A, Jafari A. Effects of creatine supplementation along with resistance training on urinary formaldehyde and serum enzymes in wrestlers. J Sports Med Phys Fitness 2014.
- Ööpik V, Pääsuke M, Timpmann S, et al. Effects of creatine supplementation during recovery from rapid body mass reduction on metabolism and muscle performance capacity in well-trained wrestlers. J Sports Med Phys Fitness. 2002;42:330-9.
- Aedma M, Timpmann S, Ööpik V. Effect of caffeine on upper-body anaerobic performance in wrestlers in simulated competition-day conditions. Int J Sport Nutr Exerc Metab. 2013 Dec; 23(6):601-9.
- Yavuz HU, Turnagol H, Demirel AH. Pre-exercise Arginine Supplementation Increases Time to Exhaustion in Elite Male Wrestlers. Biol. Sport. 2014;31:187-191.
- Jang T, Wu C, Chang C, et al. Effects of carbohydrate, branched-chain amino acids, and arginine in recovery period on the subsequent performance in wrestlers. Journal of the International Society of Sports Nutrition. 2011;8:21.
- Timpmann S, Burk A, Medijainen L, et al. Dietary sodium citrate supplementation enhances rehydration and recovery from rapid body mass loss in trained wrestlers. Appl Physiol Nutr Metab. 2012;37:1028-1037.
- Blancquaert L, Everaert I, Derave W. Beta-alanine supplementation, muscle carnosine and exercise performance. Curr Opin Clin Nutr Metab Care. 2015 Jan;18(1):63-70.
- Kern B, Robinson T. Effect of beta-alanine supplementation on performance and body composition in collegiate wrestlers and football players. Journal of the International Society of Sports Nutrition. 2009;6(Suppl I):P2.
- Powers SK, Hamilton K. Antioxidants and exercise. Clin Sports Med. 1999 Jul; 18(3):525-36.
- Kara E, Gunay M, Cicioglu I, et al. Effect of Zinc Supplementation on Antioxidant Activity in Young Wrestlers. Biol Trace Elem Res. 2010;134:55-63.
- Tartibian B, Hajizadeh Maleki B, Abbasi A. The effects of omega-3 supplementation on pulmonary function of young wrestlers during intensive training. Journal of Science and Medicine in Sport. 2010;13:281-286.
- Volpe SL. Minerals as Ergogenic Aids. Current Sports Medicine Reports. 2008 July/August;7(4):224-229.
- Walker L, Bemben M, Bemben D, et al. Chromium picolinate effects on body composition and muscular performance in wrestlers. Med. Sic. Sports Exerc. 1998;30(12):1730-1737.
- Knapik JJ, Steelman RA, Hoedebecke SS, et al. Prevalence of Dietary Supplement Use by Athletes: Systematic Review and Meta-Analysis. Sports Med. 2015 Oct, Epub ahead of print.
- Tarnopolsky MA. Gender differences in metabolism; nutrition and supplements. J Sci Med Sport. 2000 Sep;3(3):287-98.
- Tarnopolsky MA. Sex Differences in Exercise Metabolism and the Role of 17-Beta Estradiol. Med Sci Sports Exerc. 2008 Apr;40(4):648-54.
- Hickner RC, Horswill CA, et al. Test development for the study of physical performance in wrestlers following weight loss. Int J Sports Med. 1991;12(6):557-62.