Sasai H, et al. – The physicians conducted this work to determine the effective dose of an amino acid mixture comprising arginine, alanine, and phenylalanine combined with physical activity promotion in reducing abdominal fat among overweight adults. Compared with placebo, the data suggested that a medium or low dose of the amino acid mixture may facilitate abdominal fat reduction among overweight adults. A larger randomized trial with sufficient statistical power should be implemented to validate the effectiveness of this supplement.

Methods

• Physicians performed a 12-week randomized, double-blind, placebo-controlled, dose-ranging, pilot trial in Mito, Japan, from January through April 2016, and the data were analyzed from May through November 2016.
• The study subjects were 35 overweight adults, aged 20–64 years, with no regular exercise habit.
• Subjects were assigned randomly to high-dose (3,000 mg/d, n=9), medium-dose (1,500 mg/d, n=9), low-dose (750 mg/d, n=8), or placebo (0 mg/d, n=9) groups, and the test beverage containing the amino acid mixture or placebo was administered for 12 weeks.
• In this study, ll subjects maintained a physically active lifestyle during the study period through monthly physical activity promotion sessions and smartphone-based self-monitoring with wearable trackers.
• Preliminary endpoints were changes in abdominal total, subcutaneous, and visceral fat areas, assessed by computed tomography.

Results

• Of the 35 enrolled participants, 32 completed the 12-week follow-up visit.
• They exhibited evidence that the intention-to-treat analysis indicated that the changes in abdominal total fat area were -14.6 cm2 (95% confidence interval [CI], -39.6 cm2 to 10.4 cm2), -25.3 cm2 (95% CI, -71.0 cm2 to 20.3 cm2), -23.2 cm2 (95% CI, -48.0 cm2 to 1.6 cm2), and -12.5 cm2 (95% CI, -29.1 cm2 to 4.0 cm2) in the high-dose, medium-dose, low-dose, and placebo groups, respectively.
• They obtained similar outcomes for visceral and subcutaneous fat areas.
• They recorded no study-related adverse events.