A reduced carbohydrate diet improves glycemic regulation in hyperglycemic older people in a retirement home: the SAGE study.

Poor glucose regulation associated with gradual insulin resistance is a significant risk factor in several age-related chronic diseases. An eating plan that promotes a lower carbohydrate intake may have a beneficial effect on glucose metabolism. This study aimed to evaluate how a diet reduced in carbohydrate by 32% (RCHO) over a 2 month period would influence the metabolic profile of older individuals (N = 24) living in a retirement home (RH). A continuous glucose monitor was used to measure blood glucose during four periods: the standard diet before (baseline) and after (washout) the intervention, during the 4 initial days of the RCHO diet (RCHO-early), and the final days of the 2 month intervention (RCHO-end). The blood metabolic profile was also measured (glucose, ketones, insulin, triglycerides, and cholesterol). RCHO intake decreased average blood glucose compared to the standard diet in hyperglycemic participants: RCHO-early 7.8 ± 1.0 vs 7.5 ± 1.1 mM (p = 0.012) and RCHO-end 7.8 ± 1.0 vs 7.0 ± 0.9 mM (p = 0.050). In the hyperglycemic participants, the percentage of time spent in hyperglycemia (>10.0 mM) decreased by 50% during the RCHO-early (p = 0.012) and by 66% at RCHO-end (p  = 0.021) compared to baseline. Glycated hemoglobin was significantly lower at RCHO-end in both hyperglycemic and normoglycemic participants compared to baseline (p < 0.008). Plasma ketones increased threefold in hyperglycemic participants at RCHO-end compared to baseline (p < 0.028). This study shows that an RCHO diet has metabolic health benefits in an older population and confirms its safety, tolerability, and acceptability in an RH (NCT06022094).