There is a growing interest within the scientific community of whether prebiotics can aid in clinical outcomes including mood via modulation of the gut microbiota and its resulting metabolites via the gut-brain axis. This is especially prevalent given that mental health conditions are associated with cost and burden on the health care system. Yet, to date very few studies have investigated the potential effects of prebiotics to influence mood via the modulation of the gut microbiota with previous studies recording mixed results indicating further work in this area would be highly beneficial.

Several reports have suggested that poor mental health among university students is on the increase. Factors driving this; including academic pressure, overdemanding workloads, financial concerns, and peer pressure; can adversely affect academic performance and self-worth. Thus, there is an increasing need to develop new strategies to help tackle these modalities while also reducing the burden on the health system.

In recent years there has been increasing interest in the bi-directional relationship that exists between the gut and the brain, a term coined the gut-brain axis, and it is suggested to play a role in influencing mood via chemical messengers.

As diet is key manipulator of the gut microbiota one way to influence the composition of the gut is via diet and the use of functional foods including prebiotic oligosaccharides.

The idea that functional foods like prebiotics may help to affect mood holds particular appeal due to them being relatively free of side effects, cheap, readily accessible and possessing additional health benefits including improving bowel transit function and improving satiety amongst others. Yet, to date previous research on the potential for prebiotics has produced mixed results due to differences in the populations tested, doses and types of prebiotics used, and means of assessing changes in mood suggesting further work in this area would be highly beneficial.

Therefore, this present study aims to address the question "can manipulation of the gut microbiota using prebiotic oligosaccharides alone or in combination influence mental state in a taught university student population?".

Inclusion Criteria:

• Volunteer is healthy at the time of pre-examination
• Possess mild/moderately elevated levels of stress
• Volunteer is aged ≥ 18 to ≤ 45 years at the time of pre-examination
• Volunteer's BMI is ≥ 18.5 and ≤ 29.9
• Volunteer has a stool frequency of at least 3 bowel movements per week
• Volunteer is able and willing to comply with the study instructions
• Volunteer is suitable for participation in the study according to the investigator/study personnel
• Written informed consent is given by volunteer

Exclusion Criteria:

• No command of any local language
• Previously or currently diagnosed neurological or psychiatric disorders
• Previous history of renal, hepatic, cardiovascular disease or clinically significant diabetes
• Gastrointestinal disorders including IBS, IBD or other conditions that might affect the gut environment
• Food allergies or intolerances
• Using drugs (e.g. antibiotics, aspirin, proton pump inhibitors) influencing gastrointestinal function (8 weeks before intervention)
• Use of laxatives and labelled pre-and probiotics in the previous 4 weeks before the beginning of intervention
• Volunteers currently involved or will be involved in another clinical or food study
• History of drug (recreational) or alcohol abuse.
• Use of anti-depressants medication including selective serotonin receptor inhibitors or Amitriptyline for 3 months prior to commencing the trial
• Received bowel preparation for investigative procedures in the 4 weeks prior to the study
• Undergone surgical resection of any part of the bowel.
• pregnant or lactating