Munkyong Pae, PhD: No relevant financial relationship(s) with ineligible companies to disclose.
Objectives: Time-restricted feeding (TRF) has emerged as a promising dietary approach in improving metabolic parameters associated with obesity, but little is known whether it exerts benefits over obesity and metabolic disturbance associated with shiftwork and thus extended/chronic exposure to light. In the current study, we tested whether lean and obese mice under chronic light exposure could benefit from TRF intervention.
Methods: Six-week-old C57BL/6 male mice were randomly assigned into two groups and fed a low-fat diet (LFD) or a high-fat diet (HFD) ad libitum under control light condition (12-h light/12-h dark cycles) for 6 weeks. The LFD- or HFD-fed mice were further divided into three subgroups; control light condition, chronic 24-h light exposure, or chronic 24-h light exposure in combination with 10-h TRF intervention. Body weight change, food intake, and energy efficiency ratio were assessed, and adipose tissue and liver were characterized for tissue inflammation.
Results: Exposure to chronic light did not increase food intake, but did increase weight gain per caloric consumption in both lean and obese mice. The effect of chronic light exposure increased total fat mass and mean adipocyte size in lean mice but did not reach statistical significance in obese mice. The TRF intervention showed reduction in weight gain, even when adjusted by caloric consumption. Exposure to both chronic light and HFD increased Adgre1 and Ccl8 gene expression in epididymal adipose tissue, but not in the inguinal fat depot. Compared to lean mice, Itgax gene expression was significantly up-regulated in the livers of obese mice, which was further exaggerated by chronic light exposure. With TRF intervention, both lean and obese mice displayed blunted expression of inflammatory markers in adipose tissue and liver.
Conclusions: Our findings indicate that TRF normalizes inflammation associated with chronic light exposure, alone or in combination with HFD consumption. These results have clinical implications in implementing TRF intervention for prevention of obesity and metabolic syndrome associated with shiftwork.
Funding Sources: Supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIP) (NRF-2021R1A2C2004521)
