MedicalResearch.com: What are the main findings of your study?
Answer: Our research indicates that consuming larger quantities of foods included in a western dietary pattern is associated with greater cognitive decline in visuospatial functioning after 36 months. Foods included in the western dietary pattern are red and processed meats, high fat dairy products, chips, refined grains, potatoes, sweets and condiments. Visuospatial functioning is an area which includes distance and depth perception, reproducing drawings and using components to construct objects or shapes.
In contrast, adherence to the Mediterranean diet, a healthy eating pattern is associated with less decline in executive function. Foods included in the Mediterranean diet are vegetables, fruits and fish. Examples of executive function include planning and organising, problem solving and time management.
We saw no effect on other areas of cognition, including verbal and visual memory, language and attention and any of the three dietary patterns. These associations were seen after controlling for the effect of known Alzheimer’s disease risk factors including age, cardiovascular risk factors and presence of an Apolipoprotein ɛ4 allele which is the most common genetic risk factor for Alzheimer’s disease.
The world’s population is growing older due to improved healthcare and nutrition. As a result, Alzheimer’s disease prevalence is rapidly increasing. Cognitive decline is the progressive loss of cognitive functions, including memory, and may lead to dementia, of which Alzheimer’s disease is the most common type. The focus of the current research climate is shifting from understanding Alzheimer’s disease pathology and diagnosis to primary prevention and intervention strategies. Diet represents one potential intervention strategy accessible to all.
There is increasing evidence that components in the foods we consume interact with each other to impart disease protection and a higher level of health. The evidence for health benefit appears stronger when foods are inserted into synergistic dietary patterns, rather than considered as individual foods or food constituents.
Our findings are in agreement with previously published work on dietary patterns and cognitive decline. In American populations, it has been shown that higher Mediterranean diet adherence is associated with lower Alzheimer’s disease risk and slower cognitive decline. Higher consumption of a ‘whole foods’ pattern (similar to our prudent pattern) has been associated with less risk of cognitive deficits, and consumption of a ‘processed foods’ pattern (similar to our western pattern) has been associated with higher risk of cognitive deficits. Our results further highlight the importance of eating a healthy diet with respect to reducing risk for cognitive decline and Alzheimer’s disease. To our knowledge, this is the first study extensively comparing Mediterranean diet, western diet and prudent diet scores to cognitive decline in an elderly, Australian cohort, to assess protective and detrimental effects of these diets.
The aim of our study was to investigate the association of three dietary patterns — Mediterranean diet, western diet and prudent diet — with cognitive change over three years, assessed using a comprehensive memory test. Dietary data was collected using food frequency questionnaires. Our results report on data from 527 men and women from a well-characterized, Australian elderly cohort, drawn from the larger Australian Imaging, Biomarkers and Lifestyle study of ageing.
Dietary patterns have not been tested extensively for their association with maintaining cognition or reducing cognitive decline. The number of published studies in this area is fairly limited, and consequently there is a need for further investigation in well-characterized ageing cohorts. It is hoped that the information generated can be used in the development of preventative strategies against cognitive decline and Alzheimer’s disease.
Gardener SL, et al “Dietary patterns and their association with cognitive decline: data from the Australian imaging, biomarkers, and lifestyle study of ageing” SFN 2013; Abstract 89.01/FFF12.