Stefani A. Derrick

Background and Objectives: Type 2 diabetes mellitus (T2DM) is a chronic condition recognized as the inability to maintain glucose homeostasis, typically presenting with insulin resistance and systemic inflammation. With the prevalence of T2DM and major risk factors, such as prediabetes and obesity, increasing each year, the need to address risk factor reduction strategies is crucial. Materials and Methods: Twenty-two men and women, overweight-to-obese adults (BMI mean: 26.1–31.6) (age range mean: 44.6–51.8) with T2DM, indicators of prediabetes, or who were metabolically healthy, participated in Cal Poly’s Nutrition and Exercise in Type 2 Diabetes (CPNET) study. There were no significant differences in terms of age, BMI, or sex distribution among the groups at the baseline. This study’s protocol included following a Mediterranean-style diet, the daily consumption of a high-quality whey protein supplement, and physical activity recommendations for 16 weeks. Body composition data, via dual-energy X-ray absorptiometry (DXA), and fasting blood samples were collected at the baseline and following the intervention. Due to restrictions associated with the outbreak of the COVID-19 pandemic, only 13 of the 22 participants who started this study were able to return for the second data collection to complete this study following the 16-week intervention. Results: The prediabetic and T2DM groups exhibited reductions in their fasting plasma glucose (12.0 mg/dL reduction in the prediabetic group; 19.6 mg/dL reduction in the T2DM group) to that of normal and prediabetic levels, respectively, while the T2DM group also demonstrated improvement in their hemoglobin A1c (reduced from 6.8% to 6.0%) to prediabetic levels. Additionally, the metabolically healthy, overweight group exhibited significant improvements in adiposity, while the obese prediabetic and T2DM groups showed non-significant improvements in all the measured metrics of body composition. No significant changes were observed in the inflammatory biomarkers (p-values ranged from 0.395 to 0.877). Conclusions: Collectively, our results suggest that adherence to a well-balanced, nutritious diet and activity may improve the parameters of glycemic control and provide benefits to body composition that help to manage and prevent the development of T2DM. Our study was able to yield significant findings signifying that the effects of a Mediterranean-style diet are observed even for a more conservative sample size.

Non-alcoholic fatty liver disease (NAFLD) is a serious metabolic condition affecting millions of people worldwide. A “Western-style diet” has been shown to induce pediatric NAFLD with the potential disruption of skeletal muscle composition and metabolism. To determine the in vivo effect of a “Western-style diet” on pediatric skeletal muscle fiber type and fuel utilization, 28 juvenile Iberian pigs were fed either a control diet (CON) or a high-fructose, high-fat diet (HFF), with or without probiotic supplementation, for 10 weeks. The HFF diets increased the total triacylglycerol content of muscle tissue but decreased intramyocellular lipid (IMCL) content and the number of type I (slow oxidative) muscle fibers. HFF diets induced autophagy as assessed by LC3I and LC3II, and inflammation, as assessed by IL-1α. No differences in body composition were observed, and there was no change in insulin sensitivity, but HFF diets increased several plasma acylcarnitines and decreased expression of lipid oxidation regulators PGC1α and CPT1, suggesting disruption of skeletal muscle metabolism. Our results show that an HFF diet fed to juvenile Iberian pigs produces a less oxidative skeletal muscle phenotype, similar to a detraining effect, and reduces the capacity to use lipid as fuel, even in the absence of insulin resistance and obesity.

Type 2 diabetes mellitus (T2DM) is a chronic metabolic condition characterized by glucose clearance abnormalities and insufficient insulin response. Left uncontrolled, T2DM can result in serious complications and death. With no cure available currently and the prevalence of major risk factors such as pre-diabetes and the metabolic syndrome continuously increasing, there is an urgent need for effective treatments with limited or no side effects. Red raspberries (RR) contain various phytonutrients with potential for modulating insulin function, glucose, and lipid metabolism. The objective of this literature review was to investigate the potential metabolic benefits of dietary RR in individuals with T2DM and pre-diabetes. A search of major scientific databases was employed to identify peer-reviewed, in vivo, or human studies that utilized whole RR or its functional constituents as treatment. The studies examined provide evidence that RR may offer clinically beneficial effects for the prevention and management of chronic diseases through improvements in glucose handling and insulin sensitivity, adiposity, lipid profiles, ectopic lipid accumulation, inflammation, oxidative stress, and cardiac health. More human trials and in vivo studies are needed to confirm the benefits of dietary RR in T2DM and pre-diabetes and to explore the dose-dependent relationships, optimal duration, and treatment modality.