Reciprocal interactions between food intake and circadian clocks: mechanisms and pathophysiological consequences

The daily rhythm of food intake is under the control of a master clock (supra-chiasmatic nuclei) and secondary clocks in the brain (mediobasal hypothalamus, brainstem) and peripheral tissues. The master clock is reset daily by ambient light and is not synchronised by meal times. Through neuroendocrine pathways, secondary clocks receive a circadian tempo from the master clock. In addition, secondary clocks are reset by meal times, through rhythmic signals transmitted by metabolic hormones and circulating metabolites. Metabolic factors associated with certain diets, such as high-fat food, alter circadian oscillations, not only in peripheral clocks, but also in the master clock. At the molecular level, multiple interactions link intracellular metabolic processes to circadian clockwork. Metabolic pathologies are frequently associated with circadian alterations. Conversely, circadian desynchronisation or meals taken at odd times (late evening, night) are obesogenic and diabetogenic. Nevertheless, taking into account timed windows of diurnal eating has beneficial effects on metabolic health. (C) 2020 Published by Elsevier Masson SAS on behalf of Societe francaise de nutrition.