Acute and Chronic Effects of 100% Florida Orange Juice Consumption on Cognitive Performance in 7-10 Year Old Children

This study will employ a randomised 10 week, parallel groups, double blind, placebo controlled design to investigate the effects of daily supplemental orange juice compared with an equicaloric placebo orange drink on cognitive performance in 7-10 year old school children. Following screening, participants will be randomly assigned to one of two conditions: (1) Active group: 100% orange juice, (2) Placebo group: control drink (containing equivalent dose of sucrose, glucose, fructose, vitamin C and citric acid for flavour). Both the active and control groups will receive a drink daily for 10 weeks delivered as a school-based morning intervention administered by researchers. Children will also be given drinks to consume over the weekends and school holidays monitored by a drink intake diary. Participants, parents and teachers will be blind to their assigned condition. Researchers will also be blinded until completion of the data analysis.

Following a practise session at screening (week -1) to familiarise the participants with the cognitive tests and study drinks, participants will take part in 3 test sessions - at baseline (Week 0), on Day 1 of intervention (start of Week 1; acute effects) and immediately post intervention (end of Week 10; chronic effects).

At week -1 (screening) children will be tested for colour blindness (Ishihara test) and complete the Wechsler abbreviated scale of intelligence (WASI) for screening purposes. Respiratory peak flow, height, and weight will also be measured to examine the relationship between cognitive performance and physical activity.

This study design, including both the test day and morning juice supplementation, is intended to emulate the children's normal routine as far as possible. Each carton of juice will be provided mid-morning to act as a supplement to their usual diet.

Measures:

The cognitive tests included in the study are listed below:

• Immediate and delayed picture recognition
• Delayed spatial memory
• Tower of Hanoi (executive function - planning/strategy)
• Corsi block tapping test (executive function and working memory)

Inclusion criteria

• Male or female, aged 7-10 years
• Willingness to consume test drinks during the study (determined by a score of 5 on the taste testing Likert scale for both orange juice drinks [attached])
• Ability to follow verbal and simple written instructions in English
• Ability to give written consent
• Normal vision, with appropriate corrective lenses if required
• Ability to understand cognitive testing instructions and responding requirements

Exclusion criteria

• Poor general health
• Colour blindness (to be assessed at screening using Tests for Colour Blindness (Isihara, 1951)
• Behavioural difficulties or attention disorders (e.g. Attention Deficit Hyperactivity Disorder)
• Learning disabilities which interfere with the ability to understand written or verbal communications
• Inability to understand the objective of the cognitive tests, or carry out the tests
• Any food allergies or intolerances to study drinks
• Acute illness, or feelings of unwell, within the week prior to testing
• Current administration of any psychotropic medication or supplementation in the month prior to testing, or during testing
• Hearing impairment that precludes the ability to follow verbal instructions