The Effect of Date Fruit on Mood and Cognition in Healthy Adults
Condition: Mood and Cognitive Performance
Study type: Interventional

Summary: 
      A number of studies have considered the neuroprotective effects of date fruit on
      neurodegenerative diseases in animals. However, so far no study has addressed the acute
      effects of date fruit on mood and cognitive performance in humans. This study will
      investigate the acute effects of two different cultivars of Saudi dates on mood and cognitive
      performance into healthy volunteers.

      This study will follow a double blind, randomised, placebo controlled, repeated measures,
      cross over design with two active treatment arms versus placebo. Treatment orders will be
      counterbalanced with the use of a Latin Square design.

      Thirty six healthy participants aged between 18 and 35 will be recruited. Participants will
      be required to undergo a screening/training visit, followed by three measurement visits at
      weekly intervals. The trial will last for 3 months in total.
    

Detailed description: 
      Introduction Fruit of the date palm (P. dactylifera) may be considered an emerging and
      potential candidate for the development of health-promoting foods owing to its high nutritive
      values (Juhaimi, Ghafoor et al. 2012). Recently, scientific studies have revealed the
      medicinal properties of P. dactylifera in the different ripening stages by examining
      anti-inflammatory, anti-angiogenic and antibacterial activity. The anti-inflammatory activity
      of various parts of P. dactylifera have been evaluated (Shabani, Zangiabadi et al. 2013); it
      is evident from these studies that, both in vivo and in vitro, date fruits display
      anti-inflammatory activity, strongly linked to secondary metabolites and antioxidant
      behaviour.

      More than 16 published studies have investigated the physiological and the psychological
      effects of P. dactylifera on the brain using animal models. Although this domain of research
      is in its infancy , the findings are quite promising and suggest that date fruits have the
      potential to become, on the one hand, a neuroprotective agent in ischemic stroke (Majid,
      Marzieh et al. 2008), brain damage (Kalantaripour, Asadi-Shekaari et al. 2012), and
      Alzheimer's disease and (Essa, Akbar et al. 2016), on the other hand, a brain enhancer by
      attenuating impairment in cognition caused by neurodegenerative diseases (Subash, Essa et al.
      2015).

      Aim The aim of this study is to investigate the acute effects of two different cultivars of
      P. dactylifera commonly consumed in Saudi Arabia on mood and cognitive performance of healthy
      volunteers.

      Design The project will investigate the acute effects on human cognitive function and mood
      after the administration of a single dose of two different date fruits using a yogurt as the
      carrier medium against a control yoghurt matched for sugar, flavour, volume, fibers, taste
      and appearance. The study will follow a double-blind, counterbalanced, placebo controlled,
      repeated measures design, with two active treatment arms versus placebo, with one week
      between each measurement visit. Treatment orders will be counterbalanced with the use of a
      Latin Square design (Williams 1949). Participants will be randomly allocated to a treatment
      order as selected through a Williams Latin Square. Participants will be required to undergo a
      screening/training visit, followed by three measurement visits at weekly intervals. The trial
      will last for 3 months in total, which is about 2-3 weeks for each participants.

      Treatment Five different cultivars of date fruit were initially considered and screened for
      testing against cognitive performance and mood according to the following criteria;
      popularity, representation of the different maturation stages, and representation of the
      different colours, which has a great an effect on the total phenolic content. Therefore from
      the Bisir maturation stage Khasab and Birhi dates were chosen, from the Rutab maturation
      stage Sukari dates and Ajwah and Khalas dates were chosen from the Tamer maturation stage.

      After a chemical analysis of polyphenol content of the five different cultivars, the study
      was narrowed down to two different cultivars of date fruits: Khasab and Birhi. According to
      our initial analysis Khasb and Birhi cultivars contained the highest amount of polyphenols,
      and while the total sugar in all varieties was similar it was lower in these two varieties
      compared with the others tested.

      Taking the stickiness of the fruit and the high content of fibres, a total of 115g of date
      powder will be mixed into one portion of low fat yogurt (e.g. Yeo yogurt 150 g BigFish® which
      has 240kJ/56kcal), with consideration to the wet weight variation prior to freeze drying
      process. The naturally occurring sugars in the date will be quantified. The total volume of
      the treatment yogurt will be up to 265 mg. The control yogurt will be a placebo mix
      containing glucose, fructose, sucrose, fibres and food dye in order to be closely matched for
      volume, taste, appearance, texture, and energy with the treatment. Yogurts will be coded and
      prepared freshly each morning by a third party who shall not take further part in the running
      of the study. No member of the investigation team will be aware of the coding of the drinks
      until a blind-data review is completed. Both the treatments and the placebo will be provided
      to the participants in plastic cups of similar appearance.

      Participants A total of 36 healthy participants aged between 18 and 35 will be recruited
      through advertisement via poster and flyer. All participants will be required to undergo a
      screening visit.

      Study procedures:

        1. Screening All participants will be screened for any contraindications prior to the
           beginning of the study. The eligible participants will then be asked to complete the
           Cog-Track Battery four times to remove practice effects. On each of the study days,
           cognitive assessments will be conducted at baseline, 45 min post dose, 90 min post dose
           and 135 min post dose. After completing each cognitive assessment, participants will be
           asked to complete Visual Analogue Scales to assess their mood status.

        2. Study day The volunteers will be briefed about the study protocol and will sign a
           written informed consent (see appendix). The participants will arrive at the NU-Food
           research center at about 9:30 am after a 12 hour overnight fast. Measurements of height
           and weight will be taken again in order to track any change, and this will be followed
           by a completion of the baseline Cog-Track Battery, Bond-Lader Visual Analogue Scales,
           Profile of mood states questionnaire and finger-prick blood glucose test. The
           participants will then consume their treatment for that day (as allocated by the
           Williams Latin square) and be asked to sit quietly (participants may work quietly, read
           or watch TV as they wish). They will be asked to start the second period of cognitive
           performance tasks 45 min after treatment administration to coincide with another blood
           glucose test. The same tasks (cognition and blood glucose) will be collected again at 90
           min and 135 min post dose. Each of the three study visits will last approximately 3
           hours. Participants will be required to stay in the research center during breaks
           between each test/blood sample. Participants will have access to a comfortable waiting
           room. At the end of the testing day all participants will receive a standard meal (A
           sandwich and a drink). (A detailed scheduling for screening and study days can be found
           in appendixes).
    

Intervention name(s): Acute effect of two Saudi cultivars of date fruit on mood and cognitive performance
Intervention type(s): Dietary Supplement
Intervention description(s): Acute effect of two Saudi cultivars of date fruit on mood and cognitive performance at baseline, 45 post-dose, 90 min post-dose and 135 min post-dose
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: Double (Participant, Investigator)
Primary purpose: Basic Science