1 Department of Nutrition and Health, Universidade Federal de Viçosa, Viçosa, Brazil. 2 Department of Nutrition, Food Science and Physiology; Center for Nutrition Research, University of Navarra, Pamplona, Spain. 3 CIBERobn, Fisiopatología de la Obesidad y la Nutrición, Carlos III Institute, Madrid, Spain. 4 IDISNA, Navarra’s Health Research Institute, Pamplona, Spain.
Introduction: Micro RNAs (miRNAs) are essential to maintaining the metabolic homeostasis. Some of them could be used as therapeutic targets for metabolic disorders and as prognostic biomarkers of the response to hypocaloric diets. Objectives: The aim of this randomized study was to evaluate the effect of two dietary strategies for weight loss on the expression of inflammation-related miRNAs and genes in white blood cells (WBC) from individuals with metabolic syndrome (MetS). Methods: The clinical, anthropometric and biochemical characteristics of 80 individuals (40 men and 40 women; age: 48.84 ± 10.02 y.o.; body mass index: 35.41 ± 4.42 kg/m2) were evaluated before and after following two different 8-week hypocaloric diets. The RESMENA diet provided higher protein intake (24.6 ± 2.8%), average intake (7 meals/day) and total antioxidant capacity than the American Heart Association recommendations (Control diet). Moreover, RESMENA included a control of the cholesterol content and focused on low glycemic index and glycemic load foods. Total RNA was isolated from WBC and the expression of some miRNAs and genes was assessed by quantitative real-time PCR. Results: Both nutritional interventions improved most anthropometric and biochemical features. However, the expression of miR-155-3p was decreased in WBC, whereas Let- 7b was strongly upregulated as a consequence of the RESMENA diet. The changes in the expression of Let-7b, miR-125b, miR-130a, miR-132-3p and miR-422b were statistically associated with changes in the diet quality, when assessed by the Healthy Eating Index. Moreover, low consumption of lipids and saturated fat (g/day) were associated with higher expression of Let-7b after the RESMENA intervention. Conclusions: The RESMENA diet was able to induce changes in the expression of Let-7b and miR-155-3p in WBC from patients with MetS after 8 weeks. The content and the quality of the lipids from the diet may influence of the expression of Let-7b, an anti-inflammatory mediator.