The purpose of this study is to investigate the potential effects of coffee intake on gut microbiota, and mood, memory, cognition and stress response. Gut microbiota are the microorganisms that live in the digestive tracts of humans. Recent studies have found a link between gut microbiota and stress and cognitive function, known as the ‘microbiota-gut-brain axis’. In addition, coffee has previously been proposed to be prebiotic in nature, stimulating the production of beneficial bacteria in the digestive tract. In this study, we will assess the relationship between coffee intake, microbiota composition and a number of key psychological and physiological measures. We will recruit 60 healthy participants, half of those who drink coffee on a regular basis and half who do not. Those who drink coffee will be given instant coffee to drink for 3 weeks. Throughout the study, biological samples will be collected to assess differences in gut-microbiota and self-reported questionnaires will be done by participants to assess their cognition. Currently, the impact of stress and inflammation on our daily lives has a significant negative impact on brain health. Thus, research focused on promoting brain health by decreasing stress and anxiety and by improving mood, cognition and inflammatory status could have significant health benefit on the general population in the longer term. The potential of coffee to enhance gut health and positively impact on microbiota-gut-brain axis would provide further insight into the already known benefits of regular caffeine consumption.
