- Watermelon (Citrullus lanatus) is rich in lycopene and citrulline and has high phenolic content and antioxidant capacity. Previous studies demonstrate the health benefits of watermelon intake on improved blood pressure regulation along with others. Similarly, cherries, raspberries, walnuts and green tea are rich in anthocyanins, polyphenols, and polyunsaturated fatty acids and have been previously observed to improve metabolic parameters associated with obesity and a western diet.
In Study 1 we hypothesized that intake of whole watermelon and potential value-added, fiber-rich products made from watermelon rind and skin would remediate metabolic complications in C57BL/6J male mice fed a high-fat, high-cholesterol, and high-sucrose diet modeling a western-style diet. Groups of mice were provided high-fat diets plus watermelon skin, watermelon rind, or watermelon flesh for 10 weeks. Dried watermelon flesh was provided at 8% of total energy (equivalent to two servings/day) and watermelon skin and rind were added at 2.25% (w/w, dry weight of additives) of diet. Animals were provided experimental diets ad libitum. Body weights, food intake, and glucose tolerance were determined. Postmortem, serum insulin, inﬂammatory markers, cecal microbiome and the relative hepatic metabolite concentrations were measured. Supplementation with all watermelon products with a high-fat western-style diet improved fasting blood glucose, circulating serum insulin concentrations, and changes in hepatic metabolite accumulation. At modest level of supplementation (2% w/w) to HF diet, fiber-rich additives made from watermelon rind and skin further improved glucose metabolism and food efficiency and shifted microbiome composition.
In Study 2 we investigated synergistic effect of whole cherry, raspberry, walnut and green tea consumption on the remediation of metabolic complications in C57BL/6J male mice fed a western-style diet. Treatment mice were provided a high-fat diet plus cherry, raspberry, walnut and green tea (CRWG) for 10 weeks. Cherry, raspberry and walnut were provided at 1.5 servings/day and green tea powder was added at 1% (w/w) of diet, and the same experimental protocol was followed as in Study 1. Modest levels of dietary supplementation with cherry, raspberry, walnut, and green tea significantly attenuated weight gain, reduced food efficiency, improved circulating serum insulin concentrations and may have protective effects on insulin resistance development and β-cell function. Our data suggests consumption of these foods may be a synergistic approach for the prevention of metabolic syndrome.