Randomized, double-blind, placebo-controlled, linear dose, crossover study to evaluate the efficacy and safety of a green coffee bean extract in overweight subjects

Abstract

Background: Adult weight gain and obesity have become worldwide problems. Issues of cost and potential side effects of prescription weight loss drugs have led overweight and obese adults to try nutraceuticals that may aid weight loss. One promising nutraceutical is green coffee extract, which contains high concentrations of chlorogenic acids that are known to have health benefits and to influence glucose and fat metabolism. A 22-week crossover study was conducted to examine the efficacy and safety of a commercial green coffee extract product GCA™ at reducing weight and body mass in 16 overweight adults.

Methods: Subjects received high-dose GCA (1050 mg), low-dose GCA (700 mg), or placebo in separate six-week treatment periods followed by two-week washout periods to reduce any influence of preceding treatment. Treatments were counterbalanced between subjects. Primary measurements were body weight, body mass index, and percent body fat. Heart rate and blood pressure were also measured.

Results: Significant reductions were observed in body weight (-8.04 ± 2.31 kg), body mass index (-2.92 ± 0.85 kg/m(2)), and percent body fat (-4.44% ± 2.00%), as well as a small decrease in heart rate (-2.56 ± 2.85 beats per minute), but with no significant changes to diet over the course of the study. Importantly, the decreases occurred when subjects were taking GCA. Body mass index for six subjects shifted from preobesity to the normal weight range (<25.00 kg/m(2)).

Conclusion: The results are consistent with human and animal studies and a meta-analysis of the efficacy of green coffee extract in weight loss. The results suggest that GCA may be an effective nutraceutical in reducing weight in preobese adults, and may be an inexpensive means of preventing obesity in overweight adults.

Keywords: blood pressure; body fat mass; body mass index; chlorogenic acid; green coffee bean extract; heart rate; weight loss.

Figure 1

Mean weight changes over time for 16 subobese subjects. Abbreviations: WO, washout; LD, low-dose; HD, high-dose; PL, placebo.

Figure 2

Mean BMI changes over time for 16 preobese subjects. Abbreviations: WO, washout; LD, low-dose; HD, high-dose; PL, placebo.