Snack Foods and Their Impact on Mental Health and the Gut-brain Axis (NutriMood)

Inclusion Criteria: Adults aged 18-45 years old. Body mass index (BMI) between 18.50-29.99kg/m2 Score 10-29 on the patient health questionnaire anxiety and depression scale (PHQ-ADS) for mild to moderate symptoms of depression and anxiety. Individuals who regularly consume snacks (Classified as ≥2 per day excluding fruit, vegetable, nut and seed snacks). Willing to complete the 12-week intervention by adhering to snacks, complete mental health questionnaires, provide stool and blood samples, record weight and other anthropometric values and record food intake at various timepoints throughout the intervention. Willing to adhere to the protocol and provide informed consent. Fibre intake of <30g/d Willing to discontinue use of pre and probiotics during the trial. Exclusion Criteria: Dislike of intervention products. Allergy or intolerance to the intervention products Self-report occurrence of substance dependency or severe mental health conditions (e.g., psychosis, schizophrenia, eating disorder). Those with depressive disorders or anxiety disorders will be included in the trial providing they meet all other inclusion criteria. Regular consumption of experimental product as snacks and unwilling to complete a washout (no consumption for 4 weeks before baseline or during the study period). Changes to medication for depression or anxiety within the last 3 months (e.g., dosage, frequency, type) Initiation of any new medications for mental health or any form of talk therapy within the last 3 months. Intention to start or alter medication or therapy for mental health during the study. Current or previous antibiotic treatment within 4 weeks prior to the start of the study. Consumption of probiotics or prebiotic products within the 2 weeks prior to the start of the study Women who are pregnant, lactating or planning pregnancy Unexplained or unintentional weight loss in the past six months Medical history of any of the following: diabetes, major active or historic psychiatric conditions (e.g. schizophrenia), current eating disorder, alcohol abuse, active treatment for cancer in the last year, severe neurological, endocrine, renal, cardiac or pulmonary disease (or any other chronic medical condition), severe oesophagitis, gastritis or duodenitis, active diverticulitis or intestinal/colonic strictures, Coeliac disease, Crohn's disease or Ulcerative colitis, stem cell or organ transplant, gut resection surgery (excluding appendicectomy and cholecystectomy), bleeding disorder, anaphylaxis or any other major or chronic condition known to impact study outcome measures.