Micronutrient malnutrition, the deficiency of vitamins or minerals, impacts on physical and mental health, in clinical and general populations, across the life course. In older western populations the high prevalence and impact of micronutrient malnutrition is less well recognised. Low- and middle-income countries are experiencing the ‘double burden of disease’ where malnutrition coexists alongside the non-communicable diseases of aging, obesity, type 2 diabetes and cardiovascular disease. Held in December 2020, the Winter Conference of the Nutrition Society was designed to cover new areas of research and concern in micronutrient malnutrition across the life course. Common themes arising from the conference were: 1) The continuing high prevalence of micronutrient malnutrition across the life-course, in diverse populations, in high, middle and low-income countries. 2) That multiple deficiencies of micronutrients frequently exist. 3) The primary cause of deficiency is poor quality diets, of low diversity, low in micronutrient dense foods. 4) Clinical conditions, medications for common non-communicable diseases, and environmental conditions, interact with and exacerbate the effects of poor diet quality. 5) Understanding of the mechanistic effects of micronutrients is still emerging. 6) Micronutrients are necessary for maintaining immune function, which has importance for the COVID-19 epidemic. 7) Better biomarkers are needed detect and understand the effects of deficiency. 7) Dietary recommendations need to be updated regularly. Further research is needed in all these areas. Comprehensive public health and government approaches to ensure access and affordability of good quality foods to populations of all ages, particularly during the ongoing COVID-19 epidemic, are crucial.