Acute Low and Moderate Doses of a Caffeine-Free Polyphenol-Rich Coffeeberry Extract Improve Feelings of Alertness and Fatigue Resulting from the Performance of Fatiguing Cognitive Tasks

Abstract

Claims that ingested nutrients can enhance cognitive performance are common but rarely tested. Here, the influence of acute consumption of a polyphenol-rich, non-caffeinated coffeeberry extract on performance of a series of fatiguing cognitive tasks, motivation to do the cognitive tasks, and mood state responses were tested in 30 healthy adults using a block-randomized, double-blind, placebo-controlled, cross-over design. The effects of 300 and 100 mg coffeeberry extracts were compared to beverages without the extract (placebo) and with 75 mg caffeine (positive control). Outcomes were measured before and twice after beverage consumption. Significant self-reported mood effects were found for the positive control indicating sample responsiveness. The coffeeberry extract beverages had non-significant effects on the cognitive test battery performance and motivation to complete these cognitive tasks. The ingestion of the 300 mg and 100 mg coffeeberry extract beverages significantly attenuated perceptions of increased fatigue and decreased alertness resulting from the completion of the fatiguing cognitive tasks. The magnitude of these mental energizing effects was similar for the low and moderate dose extract beverages; thus, there was not support for a dose-response effect. It was concluded that beverages containing low (100 mg) and moderate (300 mg) amounts of a polyphenol-rich, non-caffeinated coffeeberry extract significantly attenuate both increases in self-reported fatigue and decreases in self-reported alertness resulting from the completion of a series of fatiguing cognitive tasks.