In nature, animals need to actively engage with the environment in order to prosper in survival and reproduction. Hence, agency is a central adaptive characteristic of animal life. In this paper, I propose that from the adaptive/functional point of view, four levels of agency can be distinguished, namely passive/reactive agency (animal being behaviourally passive or purely reactive), action-driven agency (animal behaviourally pursuing current desirable outcomes), competence-building agency (animal engaging with the environment to gain skills and information for future use) and aspirational agency (the animal achieving long-term goals through planning and autobiographical reflection). Recent progress in affective neurobiology indicates that each tier of agency is supported by a different type of affective functioning, at least in the case of mammals. Furthermore, the particular agency levels can be linked to distinct degrees of awareness as defined by recent selfhood theories. Based on this coupling between agency adaptive functioning, affective neurobiology and animal awareness levels, I examine several links between animal agency and animal welfare, including the notion of animal boredom, and discuss how animal agency might be promoted in the restrictive frameworks of intensive animal farming.

The 2019 Nutrition Society Spring Conference, which convened in Dundee, focused on the challenges presented by inter-individual differences in the responses to nutrition and in conducting nutritional research. The programme brought together national and international experts to discuss the collective evidence on inter-individual nutritional responses and impacts on health. Speakers and delegates from across the UK, Europe and the USA debated new methods of conducting research in nutrition and discussed the development of appropriate dietary interventions to maintain health and prevent disease in diverse populations. Symposium 1 focused on the effects of ethnicity on nutrient availability and type 2 diabetes and cardio-metabolic disease. Symposium 2 explored sex differences in nutrient availability and health and metabolism. The final symposium examined genetic and phenotypic variation, nutrition and health. The meeting ended with a panel discussion about how we take research to recommendations and concluded with a need to consider inter-individual differences in planning, conducting and analysing nutritional research.

Epigenetics encompasses changes to marks on the genome that are copied from one cell generation to the next, which may alter gene expression but which do not involve changes in the primary DNA sequence. These marks include DNA methylation (methylation of cytosines within CpG dinucleotides) and post-translational modifications (acetylation, methylation, phosphorylation and ubiquitination) of the histone tails protruding from nucleosome cores. The sum of genome-wide epigenetic patterns is known as the epigenome. It is hypothesised that altered epigenetic marking is a means through which evidence of environmental exposures (including nutritional status and dietary exposure) is received and recorded by the genome. At least some of these epigenetic marks are remembered through multiple cell generations and their effects may be revealed in altered gene expression and cell function. Altered epigenetic marking allows plasticity of phenotype in a fixed genotype. Despite their identical genotypes, monozygotic twins show increasing epigenetic diversity with age and with divergent lifestyles. Differences in epigenetic markings may explain some inter-individual variation in disease risk and in response to nutritional interventions.