Mood

Hydration – Improved mood

In 2014 the Public Library of Science published a study in which 22 individuals with high water intake (2.5 L/day) reduced their intake to 1 L/day and 30 participants with low water intake (1 L/day) increased their consumption to 2.5 L/day. The result was a decrease in happiness, calmness, positive emotions and vigor in the group with reduced water, while those who increased water consumption saw significant decreases in fatigue, confusion and thirst as well as lower sleepiness compared to baseline. [Source]

In 2012 The Journal of Nutrition published a placebo-controlled trial in which 25 young females were assessed at different levels of hydration. The results showed that dehydration lead to lower concentration, headaches, degraded mood and increased perception of task difficulty. [Source]

In 2010 the Journal of Alternative and Complementary Medicine published a study in which 15 subjects were assigned to a walking group and 19 were assigned to a yoga group. After 12 weeks individuals in the yoga group had greater improvements in mood and reductions anxiety. According to the authors, this is likely due to greater increases in GABA (gamma-Aminobutyric acid) – a substance which can promote relaxation – in the yoga group. [Source]

In 2007 the Journal of Psychopharmacology published a double-blind study involving 26 participants which found that 75 mg of guarana improved cognition, increased alertness and improved mood when compared to a placebo. [Source]

In 2012 Psychopharmacology published an 81-participant, double-blind study which found that energy drinks containing glucose and caffeine improved mental performance and reduced anxiety and self-reported stress levels during firefighter training. [Source]

In 2007 Obesity published a study designed to observe the effect of a low-fat diet compared with a ketogenic diet on mood and hunger in 119 overweight participants. The result was an improvement in mood and hunger in both groups over the course of the trial, though the ketogenic diet group reported fewer negative effects and less hunger than the low-fat group. [Source]