An Investigation Into the Acute Effects of Date Fruit (Phoenix Dactylifera L.) on Mood and Cognitive Performance in Healthy Volunteers.

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.