A Pilot Study of the Acute Ingestion of No. 1 Rosemary Water: Evidence of Cognitive, Physiological and Subjective Effects in Healthy Adults

This study investigated the potential impact of the acute ingestion of No. 1 Rosemary water—a commercially available carbonated water containing an extract of Rosemary (Rosmarinus officinalis). Twenty healthy adults were randomly allocated to consume either 330 ml of No. 1 Rosemary water or plain carbonated water. They then completed a series of subjective measures and cognitive tasks including a fifteen-minute session on a stress inducing multi-tasking framework, followed by a second completion of the subjective measures. Heart rate and blood pressure were monitored throughout the procedure. Given the pilot nature of the study, analysis of the data eschewed significance testing for the calculation of Cohen’s d measure of effect sizes. These revealed a number of small enhancement effects on cognition, consistent with those found previously for the inhalation of the aroma of Rosemary essential oil, and oral administration of dried herb. Of particular interest here are the reduced subjective evaluations of stress, and the blunted physiological reactivity noted for heart rate and blood pressure, which represent novel findings in this area. Taken together the data suggest further investigation of this product is warranted with regard to its potential beneficial properties