Predisposition to insulin resistance and obesity due to staple consumption of rice: Amylose content versus germination status

Type 2 diabetes is a metabolic disorder with established, well-defined precursors. Obesity and insulin resistance are amongst most important factors in predisposition to diabetes. Rice is a staple for about half the global population and its consumption has been strongly linked with diabetogenesis. We assert that tackling the prevalence of predisposing factors by modifying certain rice cultivars could reduce the global burden of obesity and insulin resistance, and by extension type 2 diabetes. Several rice cultivars with various properties were fed to nulliparous rats (five weeks old at the start of the experiment) for 90 days. They were then returned to a diet of standard pellets and mated with males raised on a standard diet. The resulting pups and dams were investigated for obesity and insulin resistance markers. We found that germination did more to reduce predisposition to obesity and insulin resistance than high amylose content. The combined reducing effect of germination and high amylose content on predisposition to obesity and insulin resistance was greater than the sum of their independent effects. Polished (white) rice with a low amylose content predisposed dams on a high-fat diet to markers of insulin resistance and obesity and this predisposition was inherited (in biochemical terms) by their F1 offspring. Overall, the results suggest that harnessing the beneficial properties of germination and amylose in rice would reduce the burden of obesity and insulin resistance, which are known to be key risk factors for development of type 2 diabetes.2型糖尿病（Type 2 diabetes）是一类存在明确前驱状态的代谢紊乱（metabolic disorder）。肥胖与胰岛素抵抗（insulin resistance）是诱发糖尿病易感的核心危险因素之一。水稻作为全球约半数人口的主食，其摄入与糖尿病发病存在显著关联。本研究认为，通过改良特定水稻品种以调控易感因素的流行程度，或可减轻全球肥胖与胰岛素抵抗的疾病负担，进而降低2型糖尿病的疾病负担。本研究将若干具有不同特性的水稻品种饲喂给实验初始周龄为5周的未生育雌性大鼠，持续90天；随后将这些大鼠转回标准颗粒饲料喂养，并与饲喂标准饲料的雄性大鼠交配。对所产幼崽与母鼠的肥胖及胰岛素抵抗相关标志物开展检测分析。结果显示，相较于高直链淀粉含量（high amylose content），发芽（germination）处理对降低肥胖与胰岛素抵抗易感风险的效果更为显著；且发芽与高直链淀粉含量二者联合对肥胖及胰岛素抵抗易感风险的降低效果，优于二者单独作用效果的总和。饲喂高脂饮食的母鼠若摄入低直链淀粉含量的精制（白）大米（polished (white) rice），会出现胰岛素抵抗与肥胖相关标志物，且该易感风险可在生化层面传递给其F1子代（F1 offspring）。综上，本研究结果表明，利用水稻发芽处理与直链淀粉的有益特性，或可减轻肥胖与胰岛素抵抗的疾病负担——而二者均为2型糖尿病发生的关键危险因素。