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Sports Supplement Product Review By Anssi Manninen, MHS MET-Rx Xtreme Amped Up Energy Pre-workout Focus and Intensity Booster Founded in 1991, MET-Rx Engineered Nutrition revolutionized the industry with a highprotein meal replacement product which actually tasted good. Over the years, MET-Rx meal replacements have been used extensively by athletes and celebrities worldwide. Continuing a commitment to well-designed products, MET-Rx recently introduced a new product line called MET-Rx Xtreme. In this article, I will discuss Xtreme Amped Up Energy, which is designed to amp up both mental and physical energy levels before training: Heat Inducer— thermogenic properties raise your body temperature to get you ready to do battle in the gym or during competition. Pre-workout Focus and Intensity Booster— to help you tear through the gym at a blistering pace. Fatty Acid Mobilizer— stimulates lipolysis to increase circulating fatty acid levels, promoting fat utilization during training sessions. The main actives of Xtreme Amped Up Energy are caffeine, green tea extract, chocamine, tyrosine and vinpocetine. So, let’s examine some science behind these ingredients. Caffeine Caffeine is probably the most popular performance-enhancing substance known to mankind. This can partly be attributed to its safety, wide availability and low price. A recent study by Doherty and Smith at the University of Luton in the UK used the meta-analytic approach (the process of synthesizing research results by using various statistical methods to retrieve, select and combine results from previous separate, but related, studies) to examine the effects of caffeine on athletic performance. The authors limited their investigation to lab-based, double-blind, fully randomized, placebo-controlled trials using adult subjects, published in peer-reviewed scientific journals. In other words, only well-controlled studies were included. As expected, the results clearly indicate that caffeine improves endurance performance and to lesser extent, high-intensity exercise. More recently, the same investigators used the meta-analysis approach to examine the effects of caffeine ingestion on ratings of perceived exertion. In comparison to fake supplementation (placebo), caffeine reduced ratings of perceived exertion during exercise by 5.6 percent. Not surprisingly, caffeine also improved exercise performance by 11.2 percent. As caffeine is a mild diuretic, some have speculated that it may have adverse effects on an athlete´s fluid balance. However, a comprehensive literature review, published in the International Journal of Sports Nutrition and Exercise Metabolism, concluded, ”Athletes and recreational enthusiasts will not incur detrimental fluid-electrolyte imbalances if they consume [caffeine] in moderation.” Green Tea Green tea has thermogenic properties and promotes fat burning beyond that explained by its caffeine content per se. A recent 12-week, double-blind study by Nagao and co-workers investigated the effects of green tea extract on body fat reduction in healthy men. Interestingly, the results revealed that bodyweight, waist circumference, body fat mass and subcutaneous fat areas were significantly lower in the green tea extract group than in the control group. Specifically, the green tea group lost about 1.4 kilograms of pure lard, while the control group lost only 0.7 kilograms (1 kilogram equals 2.2 pounds). As expected, green tea treatment had no adverse effects. In addition, there’s evidence that green tea can improve endurance performance by increasing utilization of fatty acids as a source of energy in muscles during exercise. Chocamine Chocamine is a proprietary cocoa extract containing numerous constituents. The combination of these ingredients purportedly produce a unique effect. While scientific evidence is limited, promotional literature suggests that chocamine increases athletic performance, suppresses appetite, increases lipolysis, improves mood, increases alertness and so on. The main actives of chocamine are likely methylxanthines (e.g., theobromine), biogenic amines (e.g., tyramine) and certain amino acids (e.g., tryptophan). Tyrosine Tyrosine, a non-essential amino acid, is essential for the production of catecholamine transmitters, including dopamine, noradrenaline and adrenaline. A review paper published in 1992 concluded that tyrosine may be useful in counteracting stress-related performance decrement and mood deterioration by increasing depleted brain noradrenaline levels. Vinpocetine Vinpocetine is a synthetic ethyl ester of apovincamine, a vinca alkaloid obtained from the leaves of the Lesser Periwinkle (Vinca minor). Promotional literature suggests that vinpocetine supplementation can prove “incredibly efficacious” for athletes who need to be lean and focused for competition. Vinpocetine increases blood circulation and metabolism in the brain. In three studies of older adults with memory problems associated with poor brain circulation or dementia-related disease, vinpocetine produced significantly more improvement than a placebo in performance on tests reflecting attention, concentration and memory. However, it’s unclear how vinpocetine affects healthy, young athletes. Warning Realize that Xtreme Amped Up Energy is a potent product, so read and follow all label instructions prior to use. Consult with your physician or a licensed health care professional before taking this product if you have a medical condition or if you’re taking any medication. Xtreme Amped Up Energy contains a fair dose of caffeine, so limit use of caffeine-containing medication, foods or beverages while taking this product. Too much caffeine may cause serious adverse effects. Don’t use this product if you’re pregnant or nursing. For more information on MET-Rx supplements, visit their website at www.metrx.com. If you wish to get your product featured in ”Sports Supplement Product Review,” e-mail Anssi Manninen; [email protected]. The author of this article has no financial relationship with MET-Rx. References: 1. Doherty M, Smith PM. Effects of caffeine ingestion on exercise testing: a metaanalysis. Int J Sport Nutr Exerc Metab, 2004 Dec;14(6):626-46. 2. Doherty M, Smith PM. Effects of caffeine ingestion on rating of perceived exertion during and after exercise: a meta-analysis. Scand J Med Sci Sports, 2005 Apr;15(2):69-78. 3. Armstrong LE. Caffeine, body fluid-electrolyte balance, and exercise performance. Int J Sport Nutr Exerc Metab, 2002 Jun;12(2):189-206. 4. Nagao T et al. Ingestion of a tea rich in catechins leads to a reduction in body fat and malondialdehyde-modified LDL in men. Am J Clin Nutr, 2005 Jan;81(1):122-9. 5. Murase T et al. Green tea extract improves running endurance in mice by stimulating lipid utilization during exercise. Am J Physiol Regul Integr Comp Physiol, 2006 Jun;290(6):R1550-6. 6. Tolson D. Chocamine description. http://www.1fast400.com/i62_Chocamine.html 7. Owasoyo JO et al. Tyrosine and its potential use as a countermeasure to performance decrement in military sustained operations. Aviat Space Environ Med, 1992 May;63(5):364-9. 8. Clayton S. Vinpocetine. http://www.bodybuilding.com/fun/southfacts_vin.htm 9. McDaniel LA et al. Brain-specific" nutrients: a memory cure? Nutrition, 2003 NovDec;19(11-12):957-75.