Correlation of the Mediterranean-Dietary Approaches to Stop Hypertension diet vs. ultra-processed diet with health outcomes in type 2 diabetes and hypertension: new insights from a 12-month interventional study

Abstract

Background and aims: There is ongoing debate about the optimal macronutrient and micronutrient proportions for treating type 2 diabetes (T2D) and hypertension. The objective of this study was to evaluate the dietary composition of patients participating in a 12-month interventional study with follow-up. Additionally, it aimed to evaluate the interactions and correlations between diet components and anthropometric markers, laboratory markers, and blood pressure (BP). Finally, perform a qualitative analysis of daily and postmeal satiety.

Methods: This experimental, analytical, and correlational study is a quaternary evaluation within a recently published longitudinal research. Eighty-four participants were divided into two groups: intervention: followed a Mediterranean-DASH diet for 12 months with follow-up at 15 months; control: no dietary changes. Parametric variables were compared using two-way ANOVA and Tukey post hoc test. Nonparametric variables were compared using Kruskal-Wallis with Dwass-Steel-Critchlow-Fligner post hoc test and Friedman with Durbin-Conover post hoc test. Parametric data were represented as mean ± standard deviation, nonparametric as median ± interquartile range. Linear regression was used for interaction/relation analysis, and Pearson test for correlation. Significance was P less than 0.05.

Results: Initially, both groups consumed diets high in ultra-processed foods, rich in refined carbohydrates, saturated fats, and sodium. At the 12th visit and follow-up, the intervention group showed substantial improvement in diet quality and dietary requirements ( P < 0.05). The control group maintained or worsened their diet quality ( P < 0.05). At first, both groups reported high hunger and low satiety. By the 12th month, the intervention group showed significant improvements, with 88.6% reporting postmeal fullness and 75% experiencing daily satiety. Significant positive and negative correlations ( P < 0.05) were observed in both groups. In the control group, low-density lipoprotein cholesterol (LDL-C) was correlated with trans fats and proteins; high-density lipoprotein cholesterol (HDL-C) with polyunsaturated fats; total cholesterol (TC) with proteins and monounsaturated fats; and glycated hemoglobin (HbA1c) with fibers. In the intervention group, BMI was correlated with carbohydrates; HbA1c with total fats; LDL-C with carbohydrates; glucose with proteins; TC with total fats and carbohydrates; HDL-C with total fats, polyunsaturated fats, and saturated fats; glucose with monounsaturated fats ( P < 0.05). In the intervention group, BP, heart rate, plasma, and urinary sodium levels significantly improved over time ( P < 0.05). However, no strong correlations between sodium intake and these markers were observed ( P > 0.05). In contrast, the control group showed no significant changes in BP, heart rate, plasma, or urinary sodium levels over time ( P > 0.05), nor were there any strong correlations between sodium intake and these markers ( P > 0.05). Notably, SBP, plasma, and urinary sodium levels demonstrated a significant difference between groups from the 12th month to the follow-up ( P < 0.05). Additionally, DBP differed significantly from baseline, with the intervention group initially presenting higher values, which reversed by the 12th month and persisted until follow-up ( P < 0.05).

Conclusion: The Mediterranean-DASH diet improved anthropometric, laboratory parameters, and BP in T2D and hypertension over the 12-month intervention and follow-up, whereas the ultra-processed diet worsened some of these markers. The intervention also improved satiety levels throughout the day. The quality and quantity of the diet are proportionally correlated to the anthropometric and laboratory markers. No significant strong correlations were found between plasma and urinary sodium levels, BP, or heart rate with sodium intake; only trends were observed. Nonetheless, further clinical trials are needed to establish causality, and the findings should be interpreted with caution due to the study's limitations.

Keywords: dietary patterns; high-fat diet; hypertension; moderate-carbohydrate diet; nutritional intervention; type 2 diabetes; ultra-processed.