The Influence of Hydromineral Balance on Mood in Humans: A Randomised Controlled Trial

Abstract

Regular salt intake is required for the maintenance of mineral ‐ fluid balance, although excessive intake is pathophysiological. Humans typically consume vastly more salt (sodium chloride) than is physiologically required yet the introduction of policies to reduce intake have met with only limited success. Despite this, the antecedents of salt intake are under investigated. An animal literature suggests that reducing salt increases anxiety, stress, or depression, however, human data are sparse. The aim was to determine in humans whether the consumption of salt, with or without water influenced mood. 100 young adults were exposed to a temperature of 30°C for four hours. In a 2 × 2 design participants either did or did not drink two 150ml glasses of water with either a sodium chloride (150mg) or placebo capsule. Changes in mood, thirst, body temperature, and body weight and urine osmolality were monitored. Participants reported being more energetic, more agreeable, and less depressed when they consumed salt. In addition, when participants consumed water they were less fatigued, more agreeable and less depressed. With anxiety there was a Salt × Water interaction; consuming salt resulted in a less anxiety but only in those who also consumed water. Neither salt nor water influenced ratings of confusion or confidence. These findings represent the first experimental data in humans supporting an influence of hydromineral balance on mood.