PROMED-COG: PROtein enriched MEDiterranean diet to combat undernutrition and promote healthy neuroCOGnitive ageing in older adults

Undernutrition caused by the deficiency of energy, protein, vitamins and/or minerals, is very common in older ages. Approximately 1.3 million people aged over 65 in the UK are considered to be undernourished; over 90% of whom live in their own home. Undernutrition has significant negative effects on health and well-being, especially for people living with cognitive impairment. It leads to weight loss and faster decline in memory and thinking (cognitive) functions, falls, infections, disability, hospital admissions and loss of independence. It can also significantly increase the risk of dementia in later life. Therefore, it is critical to find effective solutions to prevent undernutrition to help people at risk of cognitive impairment live healthier lives.

In this research, we will address identified gaps in existing knowledge by conducting a randomised controlled trial (PROMED-EX) in 105 undernourished adults with subjective memory complaint living in Northern Ireland. The aims of the PROMED-EX trial are to: (i) determine the effect of a protein enriched Mediterranean diet, with and without exercise, on cognitive function; (ii) understand how a protein enriched Mediterranean diet and exercise may act to influence nutritional status, and; (iii) evaluate the acceptability of diet and exercise to support better nutrition status and cognitive performance in older adults with subjective memory complaint.

PROMED-EX is part of a larger European project to study how undernutrition can affect dementia risk in later life. The project will provide new and critical insight into the role of undernutrition in brain ageing and dementia risk and how modifications of dietary and exercise behaviour can act to prevent undernutrition for healthy brain ageing in older citizens. Ultimately, the research will produce evidence-based lifestyle guidelines for prevention of undernutrition and, specifically, the promotion of healthy brain ageing in older adults.

Dementia is a major public health challenge owing to its increasing prevalence and impact on disability and quality of life among older adults. Undernutrition, defined as a 'state resulting from inadequate food intake and/or nutrient deficiencies that leads to an altered body composition and weight loss', is common in cognitive impairment and has many adverse consequences. Undernourished dementia patients experience faster functional and cognitive decline, more psychiatric symptoms, and greater risk of hospitalisation and death, compared to those who are adequately nourished. Importantly, weight loss increases dementia risk by 30-40% and precedes a diagnosis of cognitive impairment or dementia by at least one decade, providing a window of opportunity to intervene with strategies to counteract undernutrition and delay, or prevent, the onset of dementia in later life. No prior studies have evaluated the effect of diet and exercise on cognitive performance.

The PROMED-EX trial is a single blind randomised controlled trial in 105 undernourished adults with subjective cognitive decline to: (i) test the effects of a protein optimised Mediterranean diet, with and without exercise, on nutritional status and cognitive performance; (ii) generate data on the mechanistic pathways by which the diet and exercise intervention may act to influence nutritional status and cognition, and (iii) understand the acceptability of diet and exercise to support better nutrition status and cognitive performance. PROMED-EX is part of a European Consortium project (PROMED-COG) to better understand the role of undernutrition in dementia risk and and how modifications of diet and exercise behaviour can act to reduce the burden of undernutrition and neurodegeneration. The resulting scientific knowledge will be translated into public and practice recommendations to prevent undernutrition for healthy neurocognitive ageing in older European citizens.