Do athletes have to concern themselves with detoxification?

Posted by Ian Craig

Detoxification, or ‘detox’, is a concept that you will find more in the health markets than within sports nutrition. Do athletes actually need to worry about their detoxification systems? After all, they are producing so much sweat on a daily basis, and our skin is one of the primary detoxification organs. Additionally, we think of athletes as very clean-living individuals – that is, until you start delving into common sports and practices, and you realise that their emphasis is on energy and macronutrients, and not necessarily the healthiest food choices.

 I’m not going to reinvent the wheel here and justify the importance of detoxification for athletes, because I believe that Michelle Reed, with her blog ‘The importance of reducing toxin exposure for athletes’, has nicely done that work already. Instead, I will delve more deeply into the detoxification systems and unearth some of the more recent research that has been gracing the pages of sporting literature.

Firstly, I want to emphasise how energetic a process detoxification actually is. According to Muller & Yeoh (1), “detoxification processes require a greater supply of ATP, the chemical form of energy, than any other biochemical process in the body.” To put this into context – if our sport’s focus is all around calories and macronutrients, there will be no perceived difference between a commercial sports drink and a healthier one. Our athletes may then be loading the system with colourants, flavourings and artificial sweeteners – ingredients that must be detoxified, in an energy-consuming way, out of the body in order to avoid biochemical damage. Conversely, with more of a focus on health-based performance, we might consider a DIY sports drink, that is bursting with natural flavours and nature-giving antioxidants.

When we consider the liver diagram below (2), one of the most important nutrient groups, which supports phase 1, phase 2, and intermediate metabolism of toxins, is our antioxidants. They are found in the form of vitamins (A, C, E, CoQ10) and phytonutrients, which are found in all colourful plants. Additionally, our minerals selenium, copper, zinc and manganese are supportive of our antioxidant systems; glutathione peroxidase, catalase and superoxide dismutase. As you’ll see in the diagram, B-vitamins and amino acids, along with a few well-selected plant extracts (such as bioflavonoids and Silymarin), are also supportive to liver detoxification.

 Liver diagram.001

Phase 1 and phase 2 liver detoxification (2)

Let’s also break down phase 2 detoxification for a minute: it consists of sulphation, glutathione, acetylation, amino acid conjugation, methylation, and glucuronidation. Every single toxin that arrives in the body, whether exogenous or endogenous, has to go through these detoxification processes. Additionally, detoxification is required to metabolise chemicals that are innate to our body, including hormones and neurotransmitters etc., once they have fulfilled their role. If you imagine the case of an athlete, there is much more hormonal activity compared to a sedentary person, plus they are likely to be eating a much larger volume of food. So, if that food is contaminated with pesticides, herbicides, growth enhancers, antibiotics, preservatives, flavour enhancers, colourants, artificial sweeteners, and all the other array of artificial ingredients that infiltrates our food supply, you can easily see that the so-called ‘clean-living’ athlete may actually require much more detoxification activity than their sedentary counterparts. Add to this, the heavy need for antioxidants within the detoxification process – athletes in heavy training actually need a ton of antioxidants to quench the sheer amount of oxidative stress created by so much breathing!

Let’s expand on one of the detoxification phases – we will take sulphation as an example. Sulphation is required to detoxify steroid hormones, which include sex hormones and stress hormones; they are heavily required for physiological adaptation to exercise training. Additionally, this process is needed to detoxify the likes of histamine and dopamine, and adrenaline and noradrenaline, which again are heavily produced within a sporting context. The sulphation process requires sulphur-containing amino acids (cysteine, methionine, taurine), and the minerals molybdenum and selenium (3). They are present within protein sources with a full spectrum of amino acids, plus the sulphurous cruciferous and allium vegetables.

With these simple analyses of liver detoxification, it becomes incredibly clear that athletes require a much greater intake of micronutrients than their sedentary counterparts – and that is simply looking at one of many biological systems in our body. Additionally, thanks to the modern science of nutrigenomics, we now understand that some athletes, from a genetic perspective, potentially have compromised detoxification support (4) and actually require a greater intake of certain nutrients, especially nutrients derived from cruciferous and allium vegetables. A recent Russian and Polish research study (5) on athletes emphasised that a certain polymorphism of the GSTP1 gene (involved in glutathione support) is related to greater endurance performance – which could potentially have something to do with exercise-induced reactive oxygen species.

Thankfully, detoxification research has now reached the sporting world (albeit ‘fringe’ understandings), and limited scientific support has been given to including the following foods and nutrients into an athlete’s diet: broccoli extracts (6); glutathione supplementation (7); garlic (8); the Tibetan turnip (9); quercetin (10); N-acetylcysteine (11); watercress (12) and allium vegetables (13).

I’m actually just scraping the surface of the information that I presented earlier this year within module 1 of the integrative sports nutrition course, plus all the research that is actually available online. In terms of research, this is just a start – when the sports nutrition fraternity as a whole eventually accepts and embraces the importance of detoxification in an athlete’s body, and starts researching single nutrients within this role, like they have done with nitrate-rich plants and vasodilation, a plethora of information will become available to us.

For more detailed information on this and other subjects, take a look at the Certificate of Integrative Sports Nutrition course.


  1. Muller A & Yeoh C (2010). Compromised detoxification – Chapter 3. Biochemical Imbalances in disease. London, UK: Singing Dragon.
  2. Murray M & Pizzorno J (1998). Encyclopedia of Natural Medicine. 2nd Edition. Three Rivers Press.
  3. Reynolds B (2015). Nutrients for detoxification. (accessed Apr 2018).
  4. Lampe J (2009). Interindividual differences in response to plant-based diets: implications for cancer risk. Am J Clin Nutr. 89(5):1553S-1557S.
  5. Zarebska et al (2017). GSTP1 C.313A>G polymorphism in Russian and Polish athletes. Physiol Genomics. 49:127-131.
  6. Cardenia V et al (2017). Effect of broccoli extract enriched diet on liver cholesterol oxidation in rats subjected to exhaustive exercise. J Steroid Biochem Mol Biol. 169:137-144.
  7. Aoi W et al (2015). Glutathione supplementation suppress muscle fatigue induced by prolonged exercise via improved aerobic metabolism. J Int Soc Sports Nutr. 6(12):7.
  8. Damirchi A et al (2015). Salivary antioxidants of male athletes after aerobic exercise and garlic supplementation on: A randomized, double blind, placebo-controlled study. J Oral Biol Craniofac Res. 5(3):146-152.
  9. Chu B et al (2017). Effects of Tibetan turnip (Brassica rapa L.) on promoting hypoxia-tolerance in healthy humans. J Ethnopharmacol. 195:246-254.
  10. Duranti G et al (2018). Chronic consumption of quercetin reduces erythrocytes oxidative damage: Evaluation at resting and after eccentric exercise in humans. Nutr Res. 50:73-81.
  11. Paschalis V et al (2018). N-acetylcysteine supplementation increases exercise performance and reduces oxidative stress only in individuals with low levels of glutathione. Free Radic Biol Med. 115:288-297.
  12. Fogarti MC et al (2013). Acute and chronic watercress supplementation attenuates exercise-induced peripheral mononuclear cell DNA damage and lipid peroxidation. Br J Nutr. 109(2):293-301.
  13. Choi EY & Cho YO (2006). Allium vegetable diet can reduce the exercise-induced oxidative stress but does not alter plasma cholesterol profile in rats. Ann Nutr Metab. 50(2):132-8.