
Caffeine And Metabolic Rate
"Effect of JavaFit Extreme on Metabolic Rate, Substrate Utilization, and Cardiovascular Safety" was presented by Ron Mendel, Jennifer Hofheins, and Tim Ziegenfuss.
This study was conducted to examine a new "designer" coffee, JavaFit Extreme, on metabolic rate, substrate oxidation (how fuels are used in the body), and cardiovascular hemodynamics. JavaFit Extreme contains 4.4 grams of Arabica beans, with a total of 670 mg composed of garcinia cambogia extract, citrus aurantium extract, caffeine USP, and chromium polynicotinate.
After baseline testing of metabolic rate, substrate oxidation and heart rate, blood pressure, and ECG, subjects were provided brewed JavaFit Extreme of different amounts. All measurements were again conducted over a three-hour timespan to see how the coffee affected them. No negative effects were found for heart rate, blood pressure, or ECG.
However, metabolic rate increased by 8.9 percent and 25.6 percent with 1.5 and 2.0 tablespoons, respectively, of coffee provided. These data indicate JavaFit extreme has dose-dependent thermogenic properties in healthy subjects.
In my humble opinion, it would have been nice to see another group who consumed plain old coffee, to see if there were any differences among subjects in either group. Moreover, since this was an acute trial, it would be interesting to see if these changes carried over to a change in body composition with chronic use.
Take home message: JavaFit Extreme (and plain old coffee) does increase metabolic rate because of the caffeine. Of course when you load it up with sugar and cream, any positive attributes will be negated. In addition, too much caffeine is banned by the NCAA, so overloading on the stimulant is not a good idea.


Zinc And Magnesium Supplementation
"Effects Of ZMA Supplementation on the Relationship of Zinc and Magnesium to Body Composition, Strength, Sprint Performance, and Metabolic and Hormone Profiles" was presented by Colin Wilborn, et al.
Zinc and magnesium deficiencies negatively affect serum testosterone levels, impair immune function, and subsequently decrease strength in athletes. Therefore, because of smart marketing, a supplement by the name of ZMA (zinc and magnesium aspartate) has grown in popularity.
The purpose of this study was to assess plasma zinc and magnesium status on strength, body composition, and markers of anabolic/catabolic status and to determine if ZMA influences these relationships. Twenty-six males participated in this study and were assigned to either a ZMA supplement or a placebo.
Blood tests revealed that the experienced weight lifters in this study had normal zinc and magnesium status. Not surprisingly, ZMA supplementation non-significantly increased plasma zinc levels and did not affect magnesium levels. In addition, zinc levels did not correlate to body composition, hormone profiles, strength, or sprint performance variables.
Take home message: Zinc and magnesium deficiencies are rare in an otherwise healthy population. Despite the popularity of this supplement, ZMA supplementation appears to have limited value on body composition, hormonal profiles, and performance in athletes with normal zinc and magnesium status.
