Characterizing blood glucose in response to diet, physical activity and sleep in healthy individuals

Abstract

Background: Blood glucose is individually regulated and is largely affected by diet, stress, physical activity and sleep. Knowledge about individual response can contribute to more personalized dietary advice for the prevention of metabolic diseases. Individual differences in blood glucose response have not been fully elucidated in healthy individuals over time. Aim: Investigate continuous blood glucose regulation, diet and lifestyle, in healthy individuals over a minimum of four months. Method: Seven healthy women (n=2) and men (n=5) were recruited for a prospective pilot-study lasting for four months. Each participant met at OsloMet for a total of five visits. Throughout the study period, continuous glucose measurements, diet, sleep, body weight and physical activity were collected for each participant. Blood samples, anthropometric measurements and an oral glucose tolerance test (OGTT) were taken at all visits. Once a month, the participants received standardized foods to be eaten over the course of the day. The day after, participants completed an OGTT at home. Result: Over the course of a month, we found that participants logged a daily intake of 47, 17 and 32 E% from carbohydrates, protein and fat, respectively, and a fiber intake of 14 (g). The continuous blood glucose measurements showed a normal variation of 2.5-11.9 mmol/L (measurements over 2 days). Differences in postprandial glucose response were observed after intake of standardized foods. Variations in glucose response within participants after intake of standardized foods from visit to visit were also found. During sleep, blood glucose was stable and had fewer fluctuations compared to waking hours in all participants. Physical activity led to both an increase and decrease in blood glucose. Compliance for the study population was calculated for: food intake (79%), sleep (87%) and body weight (62%). Additionally, 12% of glucose data was not registered. Intake of fiber and carbohydrates from the day with standardized foods was negatively correlated with average blood glucose the day after. Conclusion: Standardized foods produce individual differences in blood glucose response. In addition, sleep and physical activity affect blood glucose response in healthy individuals. The results contribute to knowledge on how future studies can be conducted to investigate individual differences, which can be used to develop personalized dietary advice. Future studies should include user-friendly methods to ensure good compliance and reduce missing data.