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

Abstract

BackgroundThe 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/DesignMedLey 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).DiscussionTo 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 registrationAustralia and New Zealand Clinical Trials Register (ANZCTR): ACTRN12613000602729.

Benefical effects of mediterranean diet in neuroinflammation and related diseases

“…But we know that longevity is not only written in the genes, but for a good 70% must conquer day by day with healthy lifestyles. So from the earliest years of life is essential for healthy nutrition, physical exercise constant, constant mental activity, a limited use of tobacco and alcohol, a life away from polluted environments, with limited sun exposure and most importantly it is necessary to lead a life animated by many interests [124][125][126][127][128][129][130][131][132][133][134][135][136][137][138].…”

“…3) The Mediterranean Diet Score, created by Panagiotakos, evaluates the consumption of 11 categories of food products with a score from 0 to 5 depending on the portions taken weekly [124][125][126][127][128][129][130][131][132][133][134][135][136][137][138].…”

“…It is the most used fat, and this is good: it is rich in monounsaturated fatty acids and in particular of oleic acid (70-86%), thanks to this particular feature is one of the best condiments to keep under control the serum concentrations of lipoproteins very low density rich in LDL cholesterol which tends to remain in the blood and to settle on the walls of the arteries. Furthermore, the relatively high concentration of oleic acid in the membrane phospholipids, makes the cell less susceptible to oxidation, reducing the formation of pro-inflammatory molecules [124][125][126][127][128][129][130][131][132][133][134][135][136][137][138].…”

A randomised controlled intervention trial evaluating the efficacy of an Australianised Mediterranean diet compared to the habitual Australian diet on cognitive function, psychological wellbeing and cardiovascular health in healthy older adults (MedLey study): protocol paper

“…The battery assessed verbal and spatial episodic memory, verbal working memory, high order executive functions, attention and speed of processing, and is described in detail in Knight et al [24]. Briefly, the cognitive test battery included the following (in order of presentation to the participants): D-KEFs Tower of London, the Rey Auditory Verbal Learning Test, the WAIS IV Symbol Search and the WAIS IV Coding, the Stroop test, the WAIS-IV digit span forward, digit span backwards and letter-number sequencing, Initial Letter Fluency, Excluded Letter Fluency, and the Benton Visual Retention Test.…”

“…TCD is non-invasive measure of cerebrovascular responsiveness (CVR) in the middle cerebral artery (MCA) and has been described elsewhere [24]. Briefly, participants sat in a temperature-controlled room (22°C) for at least 10 min prior to commencing the assessment.…”