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The Walnuts and Healthy Aging Study (WAHA): Protocol for a Nutritional Intervention Trial with Walnuts on Brain Aging.
Rajaram, S, Valls-Pedret, C, Cofán, M, Sabaté, J, Serra-Mir, M, Pérez-Heras, AM, Arechiga, A, Casaroli-Marano, RP, Alforja, S, Sala-Vila, A, et al
Frontiers in aging neuroscience. 2016;8:333
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The prevalence of neurodegenerative disorders (ND) and age-related macular degeneration (AMD) is increasing among the elderly population. Oxidative stress and inflammation play a role in both diseases, and recent evidence has shown that walnuts, rich in omega-3 fatty acids, have potential to beneficially impact neuronal function in both the brain and retina. The aim of the Walnuts and Healthy Aging (WAHA) study is to provide an initial protocol for investigating the effects of walnut consumption on cognitive and retinal health among healthy elderly participants. The study will be conducted for two years and participants will be randomised to the placebo group or to consume walnuts daily for two years. This study expects that regular walnut consumption will have beneficial effects for delaying the onset of age-related cognitive impairment and retinal pathology.
Abstract
Introduction: An unwanted consequence of population aging is the growing number of elderly at risk of neurodegenerative disorders, including dementia and macular degeneration. As nutritional and behavioral changes can delay disease progression, we designed the Walnuts and Healthy Aging (WAHA) study, a two-center, randomized, 2-year clinical trial conducted in free-living, cognitively healthy elderly men and women. Our interest in exploring the role of walnuts in maintaining cognitive and retinal health is based on extensive evidence supporting their cardio-protective and vascular health effects, which are linked to bioactive components, such as n-3 fatty acids and polyphenols. Methods: The primary aim of WAHA is to examine the effects of ingesting walnuts daily for 2 years on cognitive function and retinal health, assessed with a battery of neuropsychological tests and optical coherence tomography, respectively. All participants followed their habitual diet, adding walnuts at 15% of energy (≈30-60 g/day) (walnut group) or abstaining from walnuts (control group). Secondary outcomes include changes in adiposity, blood pressure, and serum and urinary biomarkers in all participants and brain magnetic resonance imaging in a subset. Results: From May 2012 to May 2014, 708 participants (mean age 69 years, 68% women) were randomized. The study ended in May 2016 with a 90% retention rate. Discussion: The results of WAHA might provide high-level evidence of the benefit of regular walnut consumption in delaying the onset of age-related cognitive impairment and retinal pathology. The findings should translate into public health policy and sound recommendations to the general population (ClinicalTrials.gov identifier NCT01634841).
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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.
Knight, A, Bryan, J, Wilson, C, Hodgson, J, Murphy, K
BMC geriatrics. 2015;15:55
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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.
Abstract
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.