Inclusion Criteria:  18 to 25 years of age Willingness to provide blood samples  Exclusion Criteria:  Allergy to blueberries or any other Vaccinium species Diagnosis or symptoms of anxiety, depression, or other mental health conditions Any medically significant condition (e.g. anemia, gastrointestinal disorders, diabetes) Use of psychoactive medication or recreational drugs in the last two weeks Current use of medication that could interact with the intervention (e.g. antibiotics) Obesity or underweight Participation in other interventional studies in the last month Pregnancy or lactation