Department of Biology, Brandeis University, Waltham, MA 02453, USA.
Nutrients. 2022 Jul 26;14(15):3064. doi: 10.3390/nu14153064.
Objective: Whether dietary carbohydrate (CHO) or fat is more involved in type 2 diabetes (T2DM) induction uncomplicated by dietary fiber was addressed in a spontaneous diabetic model, the diurnal Nile rat that mimics the human condition. Methods: A total of 138 male Nile rats were fed plant-based and animal-based saturated fat where 10% energy as CHO and fat were exchanged across 5 diets keeping protein constant, from 70:10:20 to 20:60:20 as CHO:fat:protein %energy. Diabetes induction was analyzed by: 1. diet composition, i.e., CHO:fat ratio, to study the impact of diet; 2. quintiles of average caloric intake per day to study the impact of calories; 3. quintiles of diabetes severity to study the epigenetic impact on diabetes resistance. Results: High glycemic load (GLoad) was most problematic if coupled with high caloric consumption. Diabetes severity highlighted rapid growth and caloric intake as likely epigenetic factors distorting glucose metabolism. The largest weanling rats ate more, grew faster, and developed more diabetes when the dietary GLoad exceeded their gene-based metabolic capacity for glucose disposal. Diabetes risk increased for susceptible rats when energy intake exceeded 26 kcal/day and the GLoad was >175/2000 kcal of diet and when the diet provided >57% energy as CHO. Most resistant rats ate <25 kcal/day independent of the CHO:fat diet ratio or the GLoad adjusted to body size. Conclusion: Beyond the CHO:fat ratio and GLoad, neither the type of fat nor the dietary polyunsaturated/saturated fatty acid (P/S) ratio had a significant impact, suggesting genetic permissiveness affecting caloric and glucose intake and glucose disposition were key to modulating Nile rat diabetes. Fat became protective by limiting GLoad when it contributed >40% energy and displaced CHO to <50% energy, thereby decreasing the number of diabetic rats and diabetes severity.
在一种非膳食纤维复杂的自发性糖尿病模型——模拟人类情况的日节律尼罗河鼠中，探讨饮食碳水化合物（CHO）或脂肪在 2 型糖尿病（T2DM）诱导中哪个更为重要。
共给 138 只雄性尼罗河鼠喂食植物性和动物性饱和脂肪，其中 CHO 和脂肪各占 10%能量，通过 5 种饮食将 CHO:脂肪：蛋白质的能量比从 70:10:20 调整至 20:60:20，同时保持蛋白质含量不变。通过以下三种方式分析糖尿病的诱导情况：1. 饮食组成，即 CHO:脂肪比例，研究饮食的影响；2. 平均每日热量摄入的五分位数，研究热量的影响；3. 糖尿病严重程度的五分位数，研究对糖尿病抗性的表观遗传影响。
高血糖负荷（GLoad）如果与高卡路里摄入相结合，则是最成问题的。糖尿病严重程度突出了快速生长和卡路里摄入可能是扭曲葡萄糖代谢的表观遗传因素。最大的断奶大鼠在饮食的 GLoad 超过其基于基因的葡萄糖处理代谢能力时，摄入更多的热量、生长更快，并发展出更多的糖尿病。当易感大鼠的能量摄入超过 26 kcal/天时，GLoad>175/2000 kcal 饮食，并且饮食提供的 CHO 能量超过 57%时，糖尿病风险增加。大多数抗性大鼠每天摄入的热量<25 kcal，独立于 CHO:脂肪饮食比例或 GLoad 调整到体重。
除了 CHO:脂肪比例和 GLoad 之外，脂肪类型或饮食多不饱和/饱和脂肪酸（P/S）比例都没有显著影响，这表明影响热量和葡萄糖摄入以及葡萄糖处置的遗传许可性是调节尼罗河鼠糖尿病的关键。当脂肪提供的能量超过 40%并将 CHO 能量降至<50%时，通过限制 GLoad，脂肪变得具有保护作用，从而减少糖尿病大鼠的数量和糖尿病的严重程度。
