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Improve Your Health AND Lose Fat With Green Tea Extract
By kingjameskjf
Green Tea Extract (Camellia sinensis) has been consumed in India and China for centuries. It is also one of the most consumed beverages in the world. [1] Green tea comes from a shrub that is found in Asia. It often totes many medicinal claims from the prevention of cancer to weight loss.
The claims are many and will be broken down and analyzed to see what actually has merit. The specific brand I will be evaluating today is Serious Nutrition Solutions (SNS) Green Tea Extract, although it applies to more then just this brand.The claims made for this supplemental herb by the manufacturer are as follows; fat loss, enhance immune function, suppress appetite, and maximize performance. The dosing protocol calls for one capsule 2-3 times per day prior to meals. No loading or cycling is needed. [2]
Green tea is composed of various substances that are attributed to the associated health effects. There are several different polyphenols (catechins). The main one is epigallocatechin gallate (EGCG). EGCG composes most of the catechin amount at 10-50%. It is speculated that this is also the most powerful catechin. [3]
Other common claims of Green Tea Extract (GTE) are: general antioxidant, stimulant, antilipidemic, and antiatherosclerotic. GTE has been shown to help reduce cancer of the bladder, ovaries, gastric, pancreatic and esophageal organs. It has also shown to help aid in cognitive function. [3]
In considering the anticancer properties of GTE, one study showed the cancer rate for those subjects in the GTE group to be at 16% in comparison to the placebo group, which had a much higher occurrence at 46%. [4] Black tea, in contrast, actually showed to increase the cancer risk. Black tea is made by allowing the green tea leaves to ferment and oxidize before drying. [3] EGCG was also found to be effective at inhibiting the replication of two strains of HIV. [5]
Many of the anticancer benefits of GTE are also interrelated to its antioxidant properties. One study showed that the antioxidants provided protection from DNA damage. It also demonstrated the ability to both inhibit and stop the formation and progression of tumor growths that were cancerous. [6] That study correlated with another done on rats measuring the ability of GTE to prevent the inner organs from sustaining oxidative DNA damage. The study found that there was no reduction of DNA damage when the administered GTE dose was low (1.3 mg/kg body weight per day). When a higher dose of 6.5 mg/kg body weight per day was used, the researchers found that it did have a reduction in DNA damage. They also found it had protective effects of the hepatocytes, colonocytes, and lymphocytes. [7]
EGCG antioxidant activity is quite high, estimated at approximately 25-100 times the potency of vitamin C and vitamin E. The antioxidant activity of 10-40 mg of the polyphenols in GTE is greater then strawberries, carrots, broccoli, or even spinach. This is the same amount that is typically found in a cup of green tea. The antioxidant properties of the catechins protect the body from free radical oxidative damage. [1] The effects of the catechins in GTE are farther reaching then even that. When dosed at a concentration of 455-910 mg of catechin content, atherosclerotic disease risk factors and proinflammation were reduced. It also diminished the production of hemodialysis production of hypochlorous acid and hydrogen peroxide. [12] This aids in demonstrating the far-reaching health benefits that are associated with the catechin content.
The antilipidemic properties of GTE seem to be disputed between whether they impact HDL cholesterol lipoproteins positively or not. When it comes to LDL lipoproteins, the case for its efficacy is much stronger. One recent study was a meta-analysis of 14 other controlled trials, which had to meet stringent criteria to be included, to ensure accurate and applicable information. The studies comprised 1,136 subjects. The results showed that the consumption of green tea extract by the subjects “significantly lowered the total cholesterol concentration”. [8] The same study also found the LDL-cholesterol concentration to be significantly lower. However, the HDL-cholesterol concentration was not found to be statistically significant. In considering the claim of enhancing immune function, there is support to substantiate the claims of immunoprotective qualities of GTE. [9][10]
One eight-week experiment demonstrated the ability of GTE to significantly improve memory as well as learning with increased retention. [11] Another study used a combination of GTE and L-theanine to test for attention and memory in subjects that had mild cognitive impairment. Brain theta waves increased significantly, indicating cognitive alertness and the potential for cognitive improvement. [12]
Another eight-week trial with diabetics found a significant effect of GTE on serum adiponectin levels and increased insulin sensitivity. [13]
The claim of GTE maximizing performance is vague and as such can either be disputed or validated depending on what you considered to be performance enhancing. For example, one study tested reflex performance and found no difference. [11] So in consideration of that parameter, is has no efficacy. Yet, another study showed an improvement in muscle health through the mechanism of delaying necrosis via the antioxidant properties. [14] One study of four weeks showed greater merit when it used a combination of GTW with a strength resistance program. The results showed that GTE provided oxidative damage protection in both the long-term strength training group and the short-term endurance group. [24] This would support the claims of GTE helping to increase exercise performance.
Literature supports appetite suppression through a leptin receptor independent control pathway. Kao et al conducted studies that found EGCG helps to reduce food consumption through appetite modulation, supporting that claim for GTE. [15][16]
The claim that garners the most attention however, is in regards to fat loss or beta-oxidation, where fatty acids are transported to the mitochondria to be burned for energy. There are multiple proposed mechanisms supporting this claim in the research. One is that GTE increases thermogenesis. For example, several studies showed an increase in caloric expenditure, the promotion of beta-oxidation, and the stimulation of thermogenesis. [17][18][19][20][21]
A couple of these studies also demonstrated that the thermogenic effects were far greater then what could be attributed to the caffeine content of the GTE alone. [17][18]
One postulated reason is through the increase of the catecholamine norepinephrine. The GTE catechin polyphenols inhibition of catechol-O-methyltransferase enzyme keeps it from degrading norepinephrine levels. [18][20][21] A similar and more recent study found those same results and related it more specifically to EGCG “to augment and prolong sympathetic stimulation of thermogenesis”. [22]
It also mentions the catechins being associated with decreasing the risk of cardiovascular disease. Fat oxidation was shown to be accelerated through the use of GTE over placebo in another study that found the increase to be 17% greater. The contribution of total energy expenditure from fat oxidation was also much higher. Subjects were also found to have an increase in insulin sensitivity by 13%. [23]
A recent study on overweight and obese men yielded several interesting points. Subjects in the test group were administered decaffeinated GTE in the amount of 530 mg with 400 mg being total catechins. It was administered in capsule form twice a day for 6 weeks. They found that GTE had no effect or benefit in association with blood pressure or metabolic function. However, they did find that the test subjects’ body weight did decrease and that there was a protective effect against weight gain by the catechins. [25]
One bottle of SNS Green Tea Extract costs $12.95 and contains 75 capsules. At the minimum recommended manufacturer dose of 2 capsules per day, it would last 37 days. That makes it .35 cents per day. That would provide 1 gram of GTE with 50% being EGCG at 500 mg. At the maximum recommended manufacturer dose of 3 capsules per day, it would last 25 days. This would be at a cost of .52 cents per day. That would provide 1.5 g of GTE with EGCG at 750 mg. [2] It’s even cheaper at Nutraplanet at $9.99 per bottle. Serious Nutrition Solutions Green Tea Ultra (75 Capsules): Discount Green Tea Ultra Supplements
Typical recommended daily dosage is approximately 100-500 mg per day with at least 40% standardization for polyphenols. SNS GTE is at 90% for their polyphenols. [1] In searching through various studies, I found that the lower doses of GTE, particularly the EGCG, didn’t have as much impact or health benefits as higher dosages. I also found that typically, the most effective range of GTE was approximately 500mg to 1 g.
Consumption of green tea up to 20 cups per day has been shown to be safe with few side effects. Those who are sensitive may experience some restlessness, heart palpitations, and tachycardia from the caffeine content. The SNS GTE contains approximately 3 mg of caffeine per capsule. However, it is common to find GTE capsules to range from .60 mg to 20.01 mg of caffeine content. [26]
Contraindications include using GTE with; bronchodilators in large amounts as it may increase the action, beta-adrenergic blockers due to possible increase in inotropic effects, and MAOI’s due to possible hypertension. [3]
I have and am currently using this supplement myself. I have also known many other people that have as well. I don’t personally know of any adverse reactions from anybody taking GTE. I don’t necessarily feel any of the effects of GTE, but bear in mind that it is not a powerful stimulant as the caffeine content is relatively low, and it takes time for the benefits to manifest themselves. I have noticed a positive change in body composition but I can’t attribute that solely to GTE as I often take other supplements with it and combine it with an exercise and diet plan.
In reading though the plethora of research, it is very promising in many aspects of healthy living. The label claims were met and exceeded. The fat oxidation and the LDL-cholesterol lowering factors were the most studied and efficacious. There is promise for even more healthy benefits but some still require continuing research to further solidify and establish them. I would recommend this supplement because it is proven to be safe and effective.
References:
1. Talbott S.M., Hughes, K. The Health Professionals Guide to Dietary Supplements. Maryland. Lippincott, Williams& Wilkins. 2007.
2. Green Tea. Serious Nutrition Solutions website. 2012. Available at: Green-Tea | SNS - Serious Nutrition Solutions. Accessed 14 March, 2012.
3. Skidmore-Roth L. Mosby’s Handbook of Herbs and Natural Supplements. In third ed. Green Tea. Missouri. 2006. 535-539.
4. Lou SQ et al. Inhibitory effect of green tea on the carcinogenesis induced with asbestos plus benzo(a)pyrene in rat. Biomed Environ Sci. 1995. 8(1): 54-58.
5. Fassing G et al. Polyphenolic antioxidant epigallocatechin-3-gallate from green tea as a candidate anti-HIV agent. AIDS. 2002. 16(6):939-941.
6. Ahn, WS et al. Protective effects of green tea extracts (polyphenon E and EGCG) on human cervical lesions. Eur J Cancer Prev. 2003. 12(5):383-390.
7. Kager N, Ferk F, Kundi M, Wagner K, Misik M, Knasmuller S. Prevention of oxidative DNA damage in inner organs and lymphocytes of rats by green tea extract. Eur J Nutr. 2010. 49(4):227-234. Available at: www.cinahl.com/cgi-bin/refsvc?jid=2297&accno=2010656996. Accessed 8 March, 2012.
8. Zheng et al. Green tea intake lowers fasting serum total and LDL cholesterol in adults: a meta-analysis of 14 randomized controlled trials. Am J Clin Nutr. 2011. 94(2):601-610. Available at: www.cinahl.com/cgi-bin/refsvc?jid=678&accno=2011235573. Accessed 5 March, 2012.
9. Elmets CA et all. Cutaneous photoprotection from ultraviolet injury by green tea polyphenols. J Am Acad Dermatol. 2001. 44(3): 425-433.
10. Pisters et al. Phase I trial of green tea extract in adult patients with solid tumors. J Clin Oncol. 2001. 19(6):1830-1838.
11. Kaur T, Pathak CM, Pandhi P, Khanduja KL. Effects of green tea extract on learning, memory, behavior and acetylcholinesterase activity in young and old male rats. Brain Cognit. 2008. 67(1):25-30. Available at: www.cinahl.com/cgi-bin/refsvc?jid=1216&accno=2009954926. Accessed 8 March, 2012.
12. Park et al. A combination of green tea extract and L-theanine improves memory and attention in subjects with mild cognitive impairment: a double-blind placebo controlled study. J Medicinal Food. 2011. 14(4):334-43. Available at: www.cinahl.com/cgi-bin/refsvc?jid=2134&accno=2011017201. Accessed 6 March 2012.
13. Somayeh M et al. The effects of green tea extract on serum adiponectin concentration and insulin resistance in patients with type 2 diabetes mellitus. J Zanjan Univ Med Sci Health Serv. 2010. 17(70):44-57. Available at: www.cinahl.com/cgi-bin/refsvc?jid=4415&accno=2010784058. Accessed 10 March, 2012.
14. Buetler TM, et al. Green tea extract decreases muscle necrosis in mice and protects against reactive oxygen species. Am J Clin Nutr. 2002. 75(4):749-753.
15. Kao YH, Hiipakka RA, Liao S . Modulation of endocrine systems and food intake by green tea epigallocatechin gallate. Endocrinology. 2000. 141: 980-987.
16. Kao YH, Hiipakka RA, Liao S . Modulation of obesity by a green tea catechin. Am J Clin Nutr 2000. 72: 1232-1234.
17. Chantre P, Lairon D. Recent findings of green tea extract AR25 (Exolise) and its activity for the treatment of obesity. Phytomedicine. 2002. 9(1): 3-8.
18. Dulloo AG et al. Efficacy of a green tea extract rich in catechin-polyphenols and caffeine in increasing 24-h energy expenditure and fat oxidationin humans. Am J Clin Nutr. 1999. 70(6): 1040-1045.
19. Dulloo AG, Seydoux J, Girardier L, Chantre P, Vandermanders J. Green tea and thermogenesis: interactions between catechin-polyphenols, caffeine, and sympathetic activity. Int J Obes Relat Metab Disord. 2000. 24(2): 252-258.
20. Komatsu T et al. Oolong tea increases energy metabolism in Japanese females. J Med Invest. 2003. 50(3-4): 170-175.
21. Kovac EM, Lejeune MO, Nijs I, Westerterp-Plantenga MS. Effects of green tea on weight maintenance after body weight loss. Br J Nutr. 2004. 91(3): 431-437.
22. Shixian Q, VanCrey B, Shi J, kakuda Y, Jiang Y. Green tea extract thermogenesis-induced weight loss by epigallocatechin gallate inhibition of catechol-O-methyltransferase. J Medicinal Food. 2006. 9(4):451-58. www.cinahl.com/cgi-bin/refsvc?jid=2134&accno=2009503751.
23. Venables MC, Hulston CJ, Cox HR, Jeukendrup AE. Green tea extract ingestion, fat oxidation, and glucose tolerance in healthy humans. Am J Clin Nutr. 2008. 87(3): 778-84. Available at: www.cinahl.com/cgi-bin/refsvc?jid=678&accno=2009876420. Accessed 10 March, 2012.
24. Jowko E, Sacharuk J, Balasinska, B, Ostaszewski P, Charmas M, Charmas R. Green tea extract supplementation gives protection against exercise induced oxidative damage in healthy men. Nutrition Research. 2011. 31(11): 813-821.
25. Brown AL, Lane J, Holyoak C, Nicol B, Mayes AE, Dadd T. Health effects of green tea catechins in overweight and obese men: a randomized controlled cross-over trial. BR J Nutr. 2011. 106(12): 1880-9. Available at: www.cinahl.com/cgi-bin/refsvc?jid=1281&accno=2011412577. Accessed 8 March, 2012.
26. Andrews K et al. The Caffeine Contents of Dietary Supplements Commonly Purchased in the US: Analysis of 53 Products with Caffeine-containing Ingredients. Analytical Bioanalytical Chemistry. 2007.
