Type 2 diabetes mellitus (T2DM) is the most common form of DM and its prevalence is increasing worldwide. Because it is a progressive disease, prevention, early detection and disease course modification are possible. Diet plays a critical role in reducing T2DM risk. Therapeutic dietary approaches routinely recommend diets high in plant foods (i.e., vegetables, fruits, whole-grains). In addition to essential micronutrients and fiber, plant-based diets contain a wide-variety of polyphenols, specifically flavonoid compounds. Evidence suggests that flavonoids may confer specific benefits for T2DM risk reduction through pathways influencing glucose absorption and insulin sensitivity and/or secretion. The present review assesses the relationship between dietary flavonoids and diabetes risk reduction reviewing current epidemiology and clinical research. Collectively, the research indicates that certain flavonoids, explicitly anthocyanins and flavan-3-ols and foods rich in these compounds, may have an important role in dietary algorithms aimed to address diabetes risk factors and the development of T2DM.

Avocados are distinctive fruits having both fats and fibers along with various micronutrients and bioactive phytochemicals. This study aimed to assess the effects of replacing carbohydrate energy in meals with half or whole avocado on postprandial indices of metabolic and vascular health. A single-center, randomized, controlled, 3-arm, 6 h, crossover study was conducted in overweight/obese middle-aged adults (n = 31). Participants consumed energy-matched breakfast meals containing 0 g (Control), 68 g (Half-A) or 136 g (Whole-A) fresh Hass avocado on 3 separate occasions. Post-meal glycemic (p < 0.0001), insulinemic (p < 0.0001) and flow mediated vasodilation (FMD) responses were reduced compared to Control meal (p < 0.01), independent of dose. Nuclear magnetic resonance analyses indicated lower concentrations of triglyceride-rich lipoproteins and higher concentrations of larger high-density lipoprotein (HDL) particles after the Whole-A vs. the Control meal (p = 0.02, p < 0.05, respectively). Race/ethnicity influenced sub-class lipoprotein concentrations (p < 0.05). Oxidized low-density-lipoproteins, monocyte chemoattractant protein-1, and interleukin-6 were not different among meals. Tumor necrosis factor-α tended to be lower after Whole-A vs. Control meal (p = 0.07). Replacing carbohydrate components with avocados in a meal improved FMD, a measure of endothelial function, and improved glycemic and lipoprotein profiles in overweight/obese adults. The study provides insight on the acute cardio-metabolic benefits of incorporating avocados into a meal.

This study aimed to investigate the satiety effects of isocalorically replacing carbohydrate energy in a meal with avocado-derived fats and fibers. In a randomized 3-arm, 6-h, crossover clinical trial, thirty-one overweight/obese adults consumed a low-fat control meal (CON, 76% carbohydrate, 14% fat as energy, 5 g fiber, ~640 kcal) or high-fat meals similar in total fat and energy, but increasing avocado-derived fat and fiber content from half (HA, 68 g; 51% carbohydrate, 40% fat as energy, 8.6 g fiber) or whole avocado (WA, 136 g; 50% carbohydrate, 43% fat as energy, 13.1 g fiber) on three separate occasions. Visual analog scales (VAS) assessed subjective satiety over 6 h. Hormones associated with satiety/appetite were measured in blood collected immediately after VAS. Stepwise multiple regression analysis was used to assess the relationship of VAS with hormones in WA and CON. Hunger suppression was enhanced after the WA compared to CON meal (p < 0.01). Subjects indicated feeling more satisfied after both HA and WA than CON (p < 0.05). Fullness was greater after CON and WA vs. HA (p < 0.005). PYY and GLP-1 were significantly elevated after WA vs. CON (p < 0.05), while insulin was significantly higher after CON vs. WA (p < 0.0001). Ghrelin was suppressed more by CON than WA (p < 0.05). Regression analysis indicated PYY was associated with subjective satiety after WA, whereas increased insulin predicted changes in subjective satiety after CON. Replacing carbohydrates in a high-carbohydrate meal with avocado-derived fat-fiber combination increased feelings of satiety mediated primarily by PYY vs. insulin. These findings may have important implications for addressing appetite management and metabolic concerns.