A randomised controlled intervention trial evaluating the efficacy of a Mediterranean dietary pattern on cognitive function and psychological wellbeing in healthy older adults: the MedLey study.
BACKGROUND
The incidence of age-related cognitive decline is rising considerably around the world. There is evidence from a number of recent cross-sectional and prospective studies indicating positive associations between the Mediterranean dietary pattern (MedDiet) and improved cognitive outcomes among the elderly including, reduced age-related cognitive decline and enhanced age-related cognitive performance. However, to date no study has validated these associations in healthy older adult populations (≥65 years and above) with randomised evidence. The main aim of the present study is to provide justified evidence regarding the efficacy of a MedDiet approach to safely reduce the onset of cognitive decline, and promote optimal cognitive performance among healthy older adults using rigorous, randomised intervention methodology.


METHODS
MedLey is a 6-month, randomised controlled 2-cohort parallel group intervention trial, with initial assessment at baseline and repeated every three months. A sample of 166 healthy Australian men and women aged 65 years and above, with normal cognitive function and proficient in English language were recruited from metropolitan Adelaide, South Australia for the study. Participants randomly allocated to the experimental group are required to maintain an intervention dietary pattern based from the traditional Cretan MedDiet (i.e. vegetables, fruits, olive oil, legumes, fish, whole grain cereals, nuts and seeds and low consumption of processed foods, dairy products, red meat and vegetable oils) for six months, while those participants allocated to the control group are asked to maintain their customary lifestyle and diet. The primary outcome of interest is the quantitative difference in age-related cognitive performance, as measured by latent variables (cognitive constructs) sensitive to normal ageing and diet (i.e. speed of processing, memory, attention, executive functions, visual spatial and visuomotor ability). Secondary outcomes include change in biomarkers of inflammation, oxidative stress, lipid metabolism, glucose, insulin, blood flow velocity, and psychological well-being factors (i.e. stress, sleep, anxiety, depression).


CONCLUSIONS
To our knowledge this will be one of the first randomised clinical trials worldwide to provide evidence for the cause-effect relationship between the MedDiet and age-related cognitive function in a healthy older adult population (≥65 years and over).


BACKGROUND
Australia and New Zealand Clinical Trials Register (ANZCTR): ACTRN12613000602729.
School of Psychology, Social Work and Social Policy, Alliance for Research in Exercise, Nutrition and Activity (ARENA), Bonython Jubilee Building, City East Campus, Frome Road, Adelaide, SA, 5000, Australia. alissa.knight@mymail.unisa.edu.au.
Alissa
A
Knight
School of Psychology, Social Work and Social Policy, Alliance for Research in Exercise, Nutrition and Activity (ARENA), Bonython Jubilee Building, City East Campus, Frome Road, Adelaide, SA, 5000, Australia. janet.bryan@unisa.edu.au.
Janet
J
Bryan
School of Medicine, The Flinders University of South Australia, Health Sciences Building, Sturt Rd, Bedford Park, Adelaide, SA, 5042, Australia. carlene.wilson@flinders.edu.au.
Carlene
C
Wilson
School of Medicine and Pharmacology, The University of Western Australia, Stirling Highway, Crawley, Perth, WA, 6009, Australia. jonathan.hodgson@uwa.edu.au.
Jonathan
J
Hodgson
School of Health Sciences, Alliance for Research in Exercise, Nutrition and Activity (ARENA), Bonython Jubilee Building, City East Campus, Frome Road, Adelaide, SA, 5000, Australia. Karen.Murphy@unisa.edu.au.
Karen
K
Murphy
D000368:Aged; D000375:Aging / Q000502:physiology / Q000523:psychology; D001315:Australia; D003071:Cognition / Q000502:physiology*; D003072:Cognition Disorders / Q000175:diagnosis / Q000503:physiopathology / Q000517:prevention & control / Q000523:psychology; D038441:Diet, Mediterranean; D056344:Executive Function / Q000502:physiology; D005260:Female; D006801:Humans; D007249:Inflammation / Q000097:blood; D007361:Intelligence Tests; D008297:Male; D008603:Mental Health; D008991:Monitoring, Physiologic / Q000379:methods; D009520:New Zealand; D016896:Treatment Outcome