The impact of meal timing on cardiometabolic syndrome indicators in shift workers

ABSTRACT

The aims of this study were to 1) compare the inflammatory potential of night- and day-shift nurses’ diets with regard to time of day and work status and 2) explore how the timing of food intake during work and off-work is associated with cardiometabolic syndrome (CMS) risk factors between these two groups. Female nurses (N = 17; 8 day-shift and 9 night-shift) reported food intake over 9 days. On a middle day off of work, metabolic parameters were measured after an overnight fast. Energy/macronutrient intake and inflammatory potential of dietary intake (as assessed via the Dietary Inflammatory Index^TM) were calculated for nurses’ workdays, work nights, off-work days, and off-work nights. Work-night total food intake (grams) accounted for a significant amount of variance in CMS risk factors for night-shift nurses only. Increased total gram consumption during night-shift nurses’ work nights was associated with increased lipid levels – independent of the macronutrient composition of the food consumed. Alternatively, for night-shift nurses, work-day intake of several food parameters accounted for a significant proportion of variance in HDL cholesterol levels, with higher intake associated with higher HDL levels. For both day- and night-shift nurses, food intake during the day was more pro-inflammatory regardless of shift type or work status. Our novel approach of combining time-of-day-specific and work-day-specific analyses of dietary inflammatory factors and macronutrient composition with measurement of CMS risk factors suggests a link between meal timing and cardiometabolic health for shift-working nurses.

KEYWORDS:

• Circadian misalignment
• dietary inflammatory index
• dietary patterns

Funding

This research was supported by the UAB Center for Clinical and Translational Science (CCTS) Grant Number ULITR000165, the UAB Department of Vision Sciences, the UAB Comprehensive Diabetes Center, and the UAB Department of Psychiatry Office of Clinical Research. Drs. Wirth, Shivappa, and Hébert were supported by grant number R44DK103377 from NIH’s National Institute of Diabetes and Digestive and Kidney Diseases. We would like to thank the following individuals for making this study possible: the participants who gave their time, Betty Darnell and the UAB Center for Clinical and Translational Science Bionutrition Core, Sherer Thomson, and Brittny White.

Declaration of interest

Dr. Hébert owns controlling interest in Connecting Health Innovations LLC (CHI), a company planning to license the right to his invention of the dietary inflammatory index (DII) from the University of South Carolina in order to develop computer and smartphone applications for patient counseling and dietary intervention in clinical settings. Drs. Michael Wirth and Nitin Shivappa are employees of CHI.

Additional information

Funding

This research was supported by the UAB Center for Clinical and Translational Science (CCTS) Grant Number ULITR000165, the UAB Department of Vision Sciences, the UAB Comprehensive Diabetes Center, and the UAB Department of Psychiatry Office of Clinical Research. Drs. Wirth, Shivappa, and Hébert were supported by grant number R44DK103377 from NIH’s National Institute of Diabetes and Digestive and Kidney Diseases. We would like to thank the following individuals for making this study possible: the participants who gave their time, Betty Darnell and the UAB Center for Clinical and Translational Science Bionutrition Core, Sherer Thomson, and Brittny White.