Perry Barrett & Julian Mercer, University of Aberdeen, UK

https://doi.org/10.36866/pn.112.21

Meeting Preview: 13 November 2018, Marble Arch, 86 Edgware Road & Garfield House, London, UK

Circadian rhythms are ubiquitous in nature and underpin most physiological and metabolic process including the sleep wake cycle, body temperature, food intake and immunity. Over the last decade, evidence has emerged that most, if not all, cells within a mammalian system show a rhythmic expression of genes that is essential to the proper function of both the cell and the organism as a whole, while disruption of circadian rhythms can have a significant impact on physiology and metabolism. Feeding behaviour and associated metabolic responses in mammals have evolved to the 24-hour light-dark cycle, and the disruption of normal feeding behaviour can have profound effects on metabolism. Animal studies have led the way in this field, showing that disruption of a normal circadian pattern of food intake can lead to obesity and the onset of the metabolic syndrome. At the molecular level, identification of the molecular components of the circadian clock has enabled detailed studies of the consequences of the disruption of the clock at the tissue level. For example, the absence of the Bmal1 gene in adipocytes, an essential component of the molecular clock, disrupts circadian rhythms in adipose tissue, leading to obesity and development of the metabolic syndrome.

Evidence is accumulating that in humans, our intrinsic circadian rhythm has consequences for the timing of food intake. When we eat during a 24-hour period may underpin a metabolic response dependent upon the size of the meal, leading to a view that there may be an optimal time to consume meals of different caloric contents (breakfast, lunch and dinner); for example, a higher caloric intake during the middle of the day may improve parameters of the metabolic syndrome and reduce body fat.

The gut microbiome may also have a role to play in meal timing. The gut microbiome is a recently identified essential component of mammalian physiology, processing, as it does, nutrients which are important to host metabolism. Disruption of the optimal composition of the gut microflora, for example by diet, can have consequences for host metabolism. It is also becoming evident that the gut microbiome undergoes circadian oscillations and consequently impacts on host metabolism. How this integrates and impacts upon circadian rhythms and metabolic health in humans is unknown.

The realisation of the importance of the timing of food intake across a 24-hour period has established the field of chrononutrition. This is a field where understanding of basic mechanisms can have translational benefit.

In this one-day symposium, we have gathered together some of the leading researchers in the field of chrononutrition from the UK, Europe and the USA, to share their latest research from human studies and animal models, and from epidemiology to molecular mechanisms.

We are pleased to highlight a plenary lecture to be given by Satchidananda Panda from the Salk Institute, USA, whose research on circadian rhythms and time-restricted feeding has brought to prominence the importance of this field to human health.