Plain language summary
Age-related mental decline is an increasing global health problem. Dementia and Alzheimer’s Disease are progressive conditions currently viewed as incurable with no lasting pharmaceutical options. Recent evidence has indicated that diet and lifestyle may help to delay the onset and progression of mental decline. This randomised controlled trial (RCT) will aim to assess the effect of a six months dietary intervention on several mental outcomes, cardiovascular changes and general well being for subjects aged sixty-five and older. The RCT will compare the Mediterranean diet (MedDiet) with continued habitual diet (HabDiet). The MedDiet subjects will follow the traditional Cretan Mediterranean diet. Compliance will be assessed using food questionnaires and multiple blood markers. This RCT will be one of the first worldwide to provide evidence for the cause-effect relationship between the MedDiet and age-related mental function in a healthy older adults. The RCT has recruited 166 participants so will provide robust evidence. Results have yet to be published.
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/DESIGN 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). DISCUSSION 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). TRIAL REGISTRATION Australia and New Zealand Clinical Trials Register (ANZCTR): ACTRN12613000602729.