In modern, developed countries like the UK, rising life expectancy over the last century has led to an increasing proportion of people living for many years beyond retirement. This presents both opportunities and challenges for individuals and society, with the balance depending heavily on how ageing impacts on physical and mental health and resilience. This presentation will focus on the role of nutrition and other lifestyle factors in mental health in older adults, drawing on the latest research evidence from the UK and other countries. This indicates that cognitive decline and dementia are not inevitable consequences of ageing, but instead reflect a complex interplay of genetic and environmental risk factors, with diet and lifestyle playing key roles. Aspects of the typical UK diet that appear to increase the risk of age-related cognitive decline and dementia as well as poor physical health include: excessive consumption of sugar and refined carbohydrates, a relative lack of long-chain omega-3 fats; deficiencies in key micronutrients (notably some of the B vitamins), and low intakes of vegetables and fruits. Key research findings will be summarised, and their practical implications discussed.