Green Tea Extracts and Physical Fitness
Over the last few years, Green Tea and Green Tea extracts have received a great deal of notoriety. Justly so, this potent tea leaf has been studied for health benefits in such areas as mitochondrial support, cardiovascular health, inflammation, and hormonal regulation. The polyphenols – such as the tannins in the tea leaves – can decrease hyperlipidemia and thereby supporting cardiovascular health. Also helpful, the green tea polyphenols when combined with Tai Chi have helped to strengthen bone density in women with menopausal-onset osteoporosis by reducing the oxidative damage. The heart is one of the body’s largest muscles and a reduction of inflammation in the body would also benefit the heart. The high levels of the antioxidants in GTE have been demonstrated to rejuvenate the cardiac muscle. Oxidative stress, a co-factor in cardiovascular damage, is also a concern during exercise and Green Tea Extract has been helpful in quelling the damage.
One study cites that there was no benefit of Green Tea Extract (GTE) on endurance athletes, but GTE was only used for a total of 3 weeks. The short amount of time may be a potential reason for lack of efficacy. CRP was noted as decreased, but there were no other significant changes noted. Other studies demonstrate an increase in total body fat usage and an increases in endurance when using GTE and performing moderate-intense levels of endurance activity. GTE is helpful in oxidizing the fat and allowing it to be better used as an energy source. It decreases body fat and improves overall body composition. Visceral fat – the more dangerous deep abdominal layer of fat – was also reduced in a study done on rats fed a high-fat diet while supplemented with GTE.
GTE is also potentially beneficial in reducing the NF-kappaB levels and, thereby, reducing inflammation and damage to muscles. The extract also appeared to help mice with Duchenne’s be able to increase their endurance when performing a physical activity by approximately 300% in one study. This could potentially be translated to human, especially with the reduction of inflammation.
Another benefit of GTE is that it has demonstrated efficacy in lowering blood sugar and cholesterol. Unfortunately, at this point it is unknown to what extent that this occurs simply because other studies are showing that there is little change between the experimental GTE group and the placebo group.
Care should also be taken to avoid contraindications with current medications as in the case of a young woman who combined an over-the-counter weight loss product that contains green tea extract while taking the common hypothyroid prescription levothyroxine. This is of particular concern because many people who are overweight and seeking to lose weight may be on a hypothyroid medication.
Overall, Green Tea Extract is potentially beneficial in decrease fat, changing body composition, increasing endurance, lowering cholesterol levels, increasing bone mineral density and improving cardiovascular health. It is essential to find out the correct dosage from a trained professional because there is some potential of hepatic toxicity if used at the wrong dosage or in the wrong form. However, these cases are rare and can come from a multitude of supplements, which is why it is important to only use supplements from trusted and studied pharmaceutical grade providers.
1. Bajerska, J., Wozniewicz, M., Jeszka, J., Drzymala-Czyz, S., & Walkowiak, J. (2011). Green tea aqueous extract reduces visceral fat and decreases protein availability in rats fed with a high-fat diet. Nutrition Research, 31(2), 157-164.
2. Bornhoeft, J., Castaneda, D., Nemoseck, T., Wang, P., Henning, S. M., & Hong, M. Y. (2012). The Protective Effects of Green Tea Polyphenols: Lipid Profile, Inflammation, and Antioxidant Capacity in Rats Fed an Atherogenic Diet and Dextran Sodium Sulfate. Journal of Medicinal Food, 15(8), 726-732.
3. Call, J. A., Voelker, K. A., Wolff, A. V., McMillan, R. P., Evans, N. P., Hulver, M. W., … & Grange, R. W. (2008). Endurance capacity in maturing mdx mice is markedly enhanced by combined voluntary wheel running and green tea extract. Journal of Applied Physiology, 105(3), 923-932.
4. Eichenberger, P., Mettler, S., Arnold, M., & Colombani, P. C. (2010). No effects of three-week consumption of a green tea extract on time trial performance in endurance-trained men. International Journal for Vitamin and Nutrition Research, 80(1), 54-64.
5. Evans, N. P., Call, J. A., Bassaganya-Riera, J., Robertson, J. L., & Grange, R. W. (2010). Green tea extract decreases muscle pathology and NF-κB immunostaining in regenerating muscle fibers of< i> mdx mice. Clinical Nutrition, 29(3), 391-398.
6. Hsu, C. H., Tsai, T. H., Kao, Y. H., Hwang, K. C., Tseng, T. Y., & Chou, P. (2008). Effect of green tea extract on obese women: a randomized, double-blind, placebo-controlled clinical trial. Clinical nutrition, 27(3), 363-370.
7. Ichinose, T., Nomura, S., Someya, Y., Akimoto, S., Tachiyashiki, K., & Imaizumi, K. (2011). Effect of endurance training supplemented with green tea extract on substrate metabolism during exercise in humans. Scandinavian journal of medicine & science in sports, 21(4), 598-605.
8. Islam, M. S., & Choi, H. (2007). Green tea, anti-diabetic or diabetogenic: A dose response study. Biofactors, 29(1), 45-53.
9. Jówko, E., Sacharuk, J., Balasińska, B., Ostaszewski, P., Charmas, M., & Charmas, R. (2011). Green tea extract supplementation gives protection against exercise-induced oxidative damage in healthy men. Nutrition Research, 31(11), 813-821.
10. Kono, S., Shinchi, K., Wakabayashi, K., Honjo, S., Todoroki, I., Sakurai, Y., … & Katsurada, M. (1996). Relation of green tea consumption to serum lipids and lipoproteins in Japanese men. Journal of epidemiology/Japan Epidemiological Association, 6(3), 128.
11. Krishna, Y. R., Mittal, V., Grewal, P., Fiel, M. I., & Schiano, T. (2011). Acute liver failure caused by ‘fat burners’ and dietary supplements: a case report and literature review. Canadian journal of gastroenterology, 25(3), 157.
12. Kumaran, V. S., Arulmathi, K., & Kalaiselvi, P. (2009). Senescence mediated redox imbalance in cardiac tissue: Antioxidant rejuvenating potential of green tea extract. Nutrition, 25(7), 847-854.
13. Liatsos, G. D., Moulakakis, A., Ketikoglou, I., & Klonari, S. (2010). Possible green tea-induced thrombotic thrombocytopenic purpura. American Journal of Health-System Pharmacy, 67(7), 531-534.
14. Murase, T., Haramizu, S., Shimotoyodome, A., Tokimitsu, I., & Hase, T. (2006). Green tea extract improves running endurance in mice by stimulating lipid utilization during exercise. American Journal of Physiology-Regulatory, Integrative and Comparative Physiology, 290(6), R1550-R1556.
15. Opala, T., Rzymski, P., Pischel, I., Wilczak, M., & Wozniak, J. (2006). Efficacy of 12 weeks supplementation of a botanical extract-based weight loss formula on body weight, body composition and blood chemistry in healthy, overweight subjects-a randomised double-blind placebo-controlled clinical trial. European journal of medical research, 11(8), 343.
16. Qian, G., Xue, K., Tang, L., Wang, F., Song, X., Chyu, M. C., … & Wang, J. S. (2012). Mitigation of Oxidative Damage by Green Tea Polyphenols and Tai Chi Exercise in Postmenopausal Women with Osteopenia. PloS one, 7(10), e48090.
17. Shen, C. L., Chyu, M. C., Yeh, J. K., Zhang, Y., Pence, B. C., Felton, C. K., … & Wang, J. S. (2012). Effect of green tea and Tai Chi on bone health in postmenopausal osteopenic women: a 6-month randomized placebo-controlled trial. Osteoporosis International, 23(5), 1541-1552.
18. Venables, M. C., Hulston, C. J., Cox, H. R., & Jeukendrup, A. E. (2008). Green tea extract ingestion, fat oxidation, and glucose tolerance in healthy humans. The American journal of clinical nutrition, 87(3), 778-784.
