Evaluation of a new dietary strategy for the treatment of obesity and associated inflammation: endocrine and epigenetic mechanisms

Abstract

Obesity and metabolic syndrome (MetS) have become major public health problems worldwide. Dietary strategies represent the primary choice treatment. The aim of this study was to investigate the effect of a new energy-restricted dietary strategy (RESMENA) involving different dietary aspects such us a modified macronutrient profile including a moderately increased amount of proteins, an augmented meal frequency, an enhancement of low GI/GL and high antioxidant content food and with a high adherence to the Mediterranean Diet, on anthropometric, biochemical and inflammatory markers in obese subjects presenting MetS features after a nutritional intervention of 8 weeks duration. Additionally, the effectiveness of the RESMENA diet was compared with a pattern based on the American Heart Association (AHA) guidelines and potential underlying mechanisms such us hormonal influences and epigenetic modifications were studied.

It was observed that the two dietary plans were equally effective on improving anthropometric and biochemical markers. Dietary total antioxidant capacity was evidenced as the major influential element given that several anthropometric and biochemical indicators were influenced by it. Moreover, the AHA-based pattern showed to be more beneficial in order to improve the inflammation status (CRP, PAI-1, TNF-α, IL-6) associated to obesity, at least in the short-term and it was observed an association between protein intake and the inflammation condition. Interestingly, animal origin protein as a whole, and meat derived protein showed to negatively influence the inflammatory status. However associations were found neither for vegetal origin protein, nor for fish. Subsequently, the new recently discovered myokine irisin was studied. It was observed that irisin plasma concentrations decreased after following the energy-restricted dietary patterns, without differences between them, in association with body weight reduction. Then, it was evidenced that irisin levels were associated with the changes in glucose homeostasis parameters, being greater the reductions on glucose, insulin and HOMA index among the participants with higher irisin baseline levels. Finally, DNA methylation of SERPINE1 gene, which codes for PAI-1, was assessed and it was observed that the higher methylation levels at baseline, the greater reductions were observed in some obesity indicators.

In summary, these data evidenced the effectiveness of a new dietary pattern and the influence of specific dietary components on anthropometric, biochemical and inflammatory markers of obese subjects with MetS after an intervention of 8-weeks duration. Furthermore, the influence of the recently discovered irisin and the epigenetics modifications have been ¿manifested as influential in mediating the obtained outcomes.