Experimental design
This study involved two randomized placebo-controlled trials (Fig. Experiment protocolDuring the trial period, the participants of both groups consumed beverages twice a day. The matcha group consumed a beverage containing 1.5 g matcha green tea powder [contents/cup; 0.06 g water, 0.4 g protein, 0.2 g fat, 4.4 g carbohydrate, 166.5 mg total polyphenols, 94.5 mg epigallocatechin gallate (EGCG), 1.1 mg lutein, 46.4 mg vitamin K, 27 mg theanine, 488 mg dietary fiber, and 45 mg caffeine] (Nestlé Japan Ltd., Kobe, Japan). The placebo group consumed a placebo tea-flavored beverage (contents/cup; 0.06 g water, 0 g protein, 0.1 g fat, 4.4 g carbohydrate, and 45 mg caffeine) daily throughout the trial period.