Can Cranberry Juice Enhance the Cognition Accuracy and Alleviate Negative Mental Consequences During Multitasking?

This clinical trial aims to investigate the effects of a 70-day consumption of cranberry juice on cognitive and motor accuracy, mental and physiological stress, and stress response in healthy men and women between the ages of 30 and 55 who engage in multitasking. The trial will utilize a randomized, double-blinded, placebo-controlled design. It is worth noting that studies have shown that over half of middle-aged Americans experience stress, which can lead to cognitive decline and depression. Previous clinical trials have indicated that consuming polyphenol-rich foods can have positive effects on cognitive function in humans. However, no study to date has examined the long-term effects of cranberry juice consumption on cognitive performance, mental stress, and stress response specifically in individuals engaged in multitasking. Based on this gap in knowledge, the investigators hypothesize the following: (1) chronic consumption of cranberry juice will improve cognitive and motor accuracy, as well as mental and psychological stress responses in young adults subjected to intense multitasking. (2) cranberry juice consumption will alleviate the negative consequences of frequent intense multitasking, such as fatigue, mood fluctuations, cognitive impairment, and memory issues. Additionally, it is expected to have a positive impact on stress biomarkers and neurotransmitter levels. By conducting this clinical trial, the investigators aim to shed light on the potential benefits of cranberry juice consumption in improving cognitive performance, mitigating mental stress, and positively influencing stress responses in individuals who engage in intense multitasking.

Recruitment Process (Screening Process):

Potential participants who have expressed interest in participating in the study will need to complete the recruitment process (or screening process). The recruitment process contains four questionnaires: Beck's Anxiety Inventory, Beck's Depression Inventory, Columbia-Suicide Severity Rating Scale, and Screening Questionnaire. The investigators will meticulously review these questionnaires to assess the eligibility of potential participants. Potential participants who meet the criteria for participation will be invited to a Consent visit (V1) to sign the consent form formally. Conversely, if potential participants do not meet the study's qualifications, the investigators will promptly communicate the results and securely dispose of the questionnaires containing their personal information.

There will be a total of three visits (V1, V2, and V3) in this study.

* V1: Consent visit
* V2: Baseline visit
* V3: Final visit

Participants who have completed the recruitment process and are qualified for the study will need to visit the lab in person and complete the consent process (V1). During V1, participants will have enough time to complete the consent. If the participants have any questions or concerns, the investigators will provide them with the necessary information and clarification. Also, the investigators will schedule the V2 and V3 with the participants. Upon signing the consent form, participants will enter the run-in phase of the study.

Run-in phase (Day -20 - Day 0):

• Participants will start to follow the dietary restriction.

Baseline visit (V2) \& final visit (V3) (Day 0 - Day 70)

1. Participants will visit the lab on the last day of the run-in period.
2. Participants need to fast (10 h) before the blood collection.
3. Participants need to provide fecal samples.
4. Participants will complete a 24-hour food record by The Automated Self-Administered 24-Hour Dietary Assessment Tool and a dietary questionnaire on a computer.
5. Participants' body height and weight will be measured.
6. A phlebotomist will collect participants' fasting blood (20 mL).
7. Participants will be served a standardized breakfast with a cup of water (V2) or assigned juice (V3).
8. Tasks participants are going to complete:

   1. Multitasking tasks (Participants will count backward, first by 3 (Series 1), then by 7 (Series 2), and finally by 17 (Series 3) from a randomly chosen number within the 800 to 999 range. At the same time, participants will encounter rapidly diminishing dots on a computer screen and use a mouse to click on these dots as they appear. There will be a total of three series of tasks, each lasting 4 minutes, with 90-second breaks provided between each series. The entire session will span 15 minutes in total), State-trait anxiety inventory state, VAMS, heart rate, galvanic skin response, and saliva sample collection.
   2. NIH toolbox tests for cognition memory, attention, and learning ability.
   3. Assessment of emotional well-being, mental resilience, and sleep quality, and monitor participants' frustration levels, anxiety traits, mood fluctuations, stress levels, and depressive and suicidal tendencies.

V2 only: after all the tests, participants are free to leave the lab with two weeks' supply of assigned beverages (8 oz/per bottle and one bottle per day). Participants will return to the lab every other week to pick up cranberry or placebo juice. Participants will also return the empty bottle and report to study coordinators if there are any side effects or other issues. A compliance calendar will be provided to participants to remind their dietary restrictions and schedule. A token of appreciation will be given to participants every four weeks to reward compliance.

V3 only: after all the tests, participants are free to leave the lab, and their study is completed.

Eligibility Criteria:
Inclusion Criteria:

* Weight ≥110 pounds;
* Age 30-55;
* BMI 18.9-29.9 kg/m\^2;
* Education level high school and above

Exclusion Criteria:

1. Heavy caffeine user (\>300 mg caffeine/day or more than 2 cups of coffee/day);
2. Alcohol consumption (\>3 alcohol/week);
3. Smoking (≥10 years);
4. Taking cannabis products;
5. Uncontrolled hypertension;
6. Clinically diagnosed illnesses, such as diabetes, cardiovascular disease, neurological disorders, and mental diseases;
7. Taking medications (antibiotics, etc.) that may influence study outcomes;
8. Taking vitamin/mineral supplements and are not willing to stop for the duration of the study;
9. Have specific dietary restriction (prevent from consuming the standardized breakfast or dinner sandwiches);
10. Inability to perform multitasking;
11. Inability to do blood collection on arm;
12. Inability to being video recorded while performing multitasking;
13. Inability to comply with dietary restrictions for the entire duration of the study;
14. Beck's depression inventory score of ≥21 during screening;
15. Beck's anxiety inventory score ≥21 during screening;
16. Severe suicidal tendencies (≥2);
17. Having seasonal depression;
18. Pregnancy;
19. Breast-feeding;
20. Female participants will do four pregnancy tests and their menstruation cycle need to be recorded. Female participants who do not wish to do pregnancy tests or record their menstruation cycle will be excluded.