Effects of key, controversial dietary factors on inflammation, glycemic control and expression of circulating microRNAs, novel biomarkers with identified signatures in cardiometabolic disease

Abstract

Dysregulation of metabolism is a common factor across obesity, type 2 diabetes (T2D) and cardiovascular disease (CVD) and disturbs metabolic pathways that are tightly regulated at the genetic level. At this level, post-transcriptional modifiers known as microRNA are aberrantly expressed in a state of dysregulation, released into circulation and contribute to the development and severity of chronic conditions. Although a number of dietary factors influence cardiometabolic health, it is unclear whether they do so through altered miRNA expression. Therefore, we aimed to examine the impact of consuming 1) diets with and without fresh, lean beef; 2) energy-restriction diets containing higher- vs normal-protein, animal source foods; and 3) breakfasts varying in protein content on 12 a priori circulating miRNA associated with cardiometabolic disease risk in healthy, overweight populations. In our first study, we aimed to identify whether a healthy dietary pattern containing fresh, lean beef influences the expression of miRNA compared to a healthy dietary pattern void of fresh, lean beef. Further, this study sought to understand the potential associations between changes in circulating miRNA expressions and markers of cardiometabolic disease risk. The expression of miR-15b-5p was higher following the consumption of a diet containing 2 servings of fresh, lean beef/d vs. a diet void of fresh lean beef. In our second study, we aimed to identify whether an energy-restriction, higher-protein diet, containing approximately 4 servings of fresh, lean beef alters expression of circulating miRNA selected based on their recorded signatures in obesity, T2D and CVD compared to an energy-restriction, normal protein diet containing approximately 1 serving of fresh, lean beef. No differences in miRNA expression were detected between diets. The third and final study sought to examine whether the consumption of breakfast, varying in protein quantity, alters the expression of miRNA associated with cardiometabolic disease risk compared to skipping breakfast. The habitual consumption of HP breakfast resulted in higher expression of miR-126-3p and miR-223-3p compared to breakfast skipping. Collectively, these studies aid in informing future dietary recommendations concerning the impact of key dietary factors on metabolic disease risk and assist in understanding the contribution of miRNA activity in this context.Nutritional Science