Latest revision as of 13:21, 23 February 2013

Quercetin as a supplement from Jarrow.

Quercetin is a naturally occurring Flavonoid found in many fruits and vegetables that may improve performance. Quercetin has a long term effect and is generally taken for at least 2-3 weeks rather than immediately before or during exercise. Quercetin is the active ingredient in the FRS range of products, but Quercetin supplements are more cost effective.

1 Quercetin and Performance

Some studies have shown improvement in V̇O₂max and endurance in untrained individuals^[1][2] and improved endurance in elite cyclists^[3]. However, a number of other studies have shown no improvement ^{[4][5][6][7][8]}. These studies have used an average of 1000mg per day (600-2000mg range) for an average of 11 days^[9]. Overall, these studies suggest that Quercetin may improve performance of up to 3%^[9]. (A 3% improvement would be 5 minutes on a 3 hour marathon, or 7 minutes on a 4 hour marathon.) In addition, it is possible that Quercetin may reduce colds (Upper respiratory tract infections) during training^[10].

2 Drug Interactions and Cautions

Quercetin may interact with a large number of drugs including antibiotics and estrogen^[11]. It would be prudent to talk to your doctor before taking Quercetin if you are on any medication.

3 Sources of Quercetin

It's hard to get sufficient Quercetin from natural sources. One of the better sources is apples, that provide 4.4mg/100g^[12], but that requires you to eat 25Lb (11Kg) of apples per day, which is impractical. The most highly advertised source of Quercetin is from the FRS range of products. These products are convenient, but expensive; getting 1000mg per day would cost $3-5 per day. A more cost effective approach is to take Quercetin as a supplement. For instance Jarrow Quercetin is $12 for 50 days.

4 Mechanism of Action

How does Quercetin work? The leading proposal is that it increases the number of mitochondria which are the parts of the cell that produce energy. This has been shown to occur in animals^[13], but so far this has not been replicated in humans. A second proposal is that Quercetin works like Caffeine, but this does not seem to be reasonable given that the effects of Quercetin are not immediate^[14]. The level of Quercetin in the blood at the time of testing is not related to the performance improvement^[9].

5 Recommendations

There is sufficient evidence to make Quercetin worthy of consideration for those not taking any medications that may have adverse interactions. 1000mg per day, split into two or more doses for at least two weeks seems to be a commonly used approach in studies, but there is nothing to indicate if this is the optimum dose.

6 References

1. ↑ Davis JM, Carlstedt CJ, Chen S, Carmichael MD, Murphy EA, The dietary flavonoid quercetin increases VO(2max) and endurance capacity., Int J Sport Nutr Exerc Metab, 2010, volume 20, issue 1, pages 56-62, PMID 20190352
2. ↑ Nieman DC, Williams AS, Shanely RA, Jin F, McAnulty SR, Triplett NT et al., Quercetin's influence on exercise performance and muscle mitochondrial biogenesis., Med Sci Sports Exerc, 2010, volume 42, issue 2, pages 338-45, PMID 19927026, doi 10.1249/MSS.0b013e3181b18fa3
3. ↑ MacRae HS, Mefferd KM, Dietary antioxidant supplementation combined with quercetin improves cycling time trial performance., Int J Sport Nutr Exerc Metab, 2006, volume 16, issue 4, pages 405-19, PMID 17136942
4. ↑ Ganio MS, Armstrong LE, Johnson EC, Klau JF, Ballard KD, Michniak-Kohn B et al., Effect of quercetin supplementation on maximal oxygen uptake in men and women., J Sports Sci, 2010, volume 28, issue 2, pages 201-8, PMID 20054739, doi 10.1080/02640410903428558
5. ↑ Cureton KJ, Tomporowski PD, Singhal A, Pasley JD, Bigelman KA, Lambourne K et al., Dietary quercetin supplementation is not ergogenic in untrained men., J Appl Physiol, 2009, volume 107, issue 4, pages 1095-104, PMID 19679747, doi 10.1152/japplphysiol.00234.2009
6. ↑ Bigelman KA, Fan EH, Chapman DP, Freese EC, Trilk JL, Cureton KJ, Effects of six weeks of quercetin supplementation on physical performance in ROTC cadets., Mil Med, 2010, volume 175, issue 10, pages 791-8, PMID 20968271
7. ↑ Sharp MA, Hendrickson NR, Staab JS, McClung HL, Nindl BC, Michniak-Kohn BB, Effects of short-term quercetin supplementation on soldier performance., J Strength Cond Res, 2012, volume 26 Suppl 2, pages S53-60, PMID 22614228, doi 10.1519/JSC.0b013e31825cf22d
8. ↑ Utter AC, Nieman DC, Kang J, Dumke CL, Quindry JC, McAnulty SR et al., Quercetin does not affect rating of perceived exertion in athletes during the Western States endurance run., Res Sports Med, 2009, volume 17, issue 2, pages 71-83, PMID 19479626, doi 10.1080/15438620902901474
9. ↑ ^{9.0 9.1 9.2} Kressler J, Millard-Stafford M, Warren GL, Quercetin and endurance exercise capacity: a systematic review and meta-analysis., Med Sci Sports Exerc, 2011, volume 43, issue 12, pages 2396-404, PMID 21606866, doi 10.1249/MSS.0b013e31822495a7
10. ↑ Nieman DC, Henson DA, Gross SJ, Jenkins DP, Davis JM, Murphy EA et al., Quercetin reduces illness but not immune perturbations after intensive exercise., Med Sci Sports Exerc, 2007, volume 39, issue 9, pages 1561-9, PMID 17805089, doi 10.1249/mss.0b013e318076b566
11. ↑ QUERCETIN: Uses, Side Effects, Interactions and Warnings - WebMD http://www.webmd.com/vitamins-supplements/ingredientmono-294-QUERCETIN.aspx?activeIngredientId=294&activeIngredientName=QUERCETIN
12. ↑ USDA Database for the Flavonoid Content of Selected Foods – 2003 http://www.nal.usda.gov/fnic/foodcomp/Data/Flav/flav.pdf
13. ↑ Davis JM, Murphy EA, Carmichael MD, Davis B, Quercetin increases brain and muscle mitochondrial biogenesis and exercise tolerance., Am J Physiol Regul Integr Comp Physiol, 2009, volume 296, issue 4, pages R1071-7, PMID 19211721, doi 10.1152/ajpregu.90925.2008
14. ↑ Cheuvront SN, Ely BR, Kenefick RW, Michniak-Kohn BB, Rood JC, Sawka MN, No effect of nutritional adenosine receptor antagonists on exercise performance in the heat., Am J Physiol Regul Integr Comp Physiol, 2009, volume 296, issue 2, pages R394-401, PMID 19020291, doi 10.1152/ajpregu.90812.2008