Effects of a 12-Month Nutritional Intervention on Ambulatory Blood Pressure and Nocturnal Dipping in Patients with Type 2 Diabetes, Hypertension, and Overweight or Obesity

BACKGROUND Ambulatory blood pressure monitoring (ABPM) provides a 24-hour profile of blood pressure, including wakefulness and sleep periods, offering superior prognostic value compared with office measurements. Although nutritional interventions improve metabolic outcomes, their long-term effects on ABPM in high-risk populations remain insufficiently studied. This study aims to assess 12-month nutritional intervention effects on ABPM in patients with hypertension, type 2 diabetes (T2D), and overweight or obesity. METHODS In this prospective, non-randomized longitudinal study, 84 patients with T2D, hypertension, and overweight or obesity were enrolled: 44 received individualized nutritional counseling focused on dietary quality and caloric control, while 40 served as controls with standard medical care. ABPM was performed at baseline and after 12 months, assessing systolic (SBP) and diastolic blood pressure (DBP) during 24-hour, wakefulness, and sleep periods, as well as nocturnal dipping status. RESULTS The intervention group showed significant reductions in 24-hour SBP (-11.94 mmHg, p = 0.013), 24-hour DBP (-6.44 mmHg, p = 0.028), wakefulness SBP (-10.27 mmHg, p = 0.042), sleep SBP (-12.03 mmHg, p = 0.017), and sleep DBP (-10.89 mmHg, p < 0.001; large effect size). Wakefulness DBP demonstrated a non-significant trend (-5.43 mmHg, p = 0.070). Adjusted analyses confirmed that sex, age, disease duration, weight, and BMI did not substantially alter outcomes. Dipping status improved significantly, with more patients converting from non-dipper to dipper (McNemar p = 0.027). CONCLUSION A structured nutritional intervention was associated with clinically meaningful improvements in ABPM parameters, during sleep, and with restoration of nocturnal dipping patterns. These findings suggest that long-term dietary modification may contribute to improved circadian blood pressure regulation. Randomized controlled trials with larger, more diverse populations are needed to confirm these findings and clarify underlying mechanisms.