Diabetes Care: 果糖摄入降低胰岛素敏感性

高热卡、高果糖饮食对胰岛素敏感性及脂代谢的不良影响已被反复证实。但是，摄入与日常相近量的果糖对糖脂代谢的影响还不确定。为了评价与摄入葡萄糖相比，中等量的果糖和蔗糖摄入对糖脂代谢的影响有无差异，来自瑞士苏黎世大学医院的Kaspar Berneis博士及其团队进行了一项研究，该研究发现中等量的果糖或蔗糖摄入能改变肝脏胰岛素敏感性。该研究结果发表在2013年1月的美国《糖尿病治疗》（Diabetes Care）杂志上。

该研究中，9位体重正常的健康男性志愿者（21-25岁）参与了此项双盲、随机对照、交叉试验。所有的受试者连续三周摄入四种加糖饮料（600毫升/天），分别为：中量果糖（MF）40克/天，大量果糖（HF），大量葡萄糖（HG），大量蔗糖（HS）各80克/天。采用高胰岛素-正葡萄糖钳夹技术，以[6,6]-²H₂葡萄糖标记测定内源性葡萄糖的产生。空腹抽血测定血脂、血糖和胰岛素水平。

该研究结果表明，钳夹标记显示，与摄入HG相比，摄入HF后肝糖抑制作用减弱（59.4±11.0% vs. 70.3 ± 10.5%, P < 0.05），然而空腹血糖、胰岛素及C肽水平在各干预组没有显著差异。与摄入HG相比，摄入MF、HF、HS后的LDL-c和总胆固醇水平明显升高。游离脂肪酸水平在摄入MF后即显著升高，但在摄入HF和HS后无明显变化（P＜0.05）。受试者在各干预过程中的能量摄入与基线没有显著差异。

研究发现，与相近量的葡萄糖摄入相比，中等量的果糖或蔗糖即能显著改变肝脏胰岛素敏感性和脂质代谢过程。

与胰岛素敏感相关的拓展阅读：

• Diabetes：郭非凡等揭示下丘脑ATF4调控肝脏胰岛素敏感性的新功能
• Diabetes:早产者较足月产者胰岛素敏感性稍低
• Diabetes Care：提高胰岛素敏感性减少肥胖者食物渴求
• JCI：脂肪细胞铁水平调节脂联素和胰岛素敏感性
• Diabetes Care：中量果糖蔗糖改善胰岛素敏感性
• Diabetes Care:阻塞性睡眠呼吸暂停影响胰岛素敏感性和分泌
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Moderate amounts of fructose consumption impair insulin sensitivity in healthy young men: a randomized controlled trial.
OBJECTIVE
Adverse effects of hypercaloric, high-fructose diets on insulin sensitivity and lipids in human subjects have been shown repeatedly. The implications of fructose in amounts close to usual daily consumption, however, have not been well studied. This study assessed the effect of moderate amounts of fructose and sucrose compared with glucose on glucose and lipid metabolism.
RESEARCH DESIGN AND METHODS
Nine healthy, normal-weight male volunteers (aged 21-25 years) were studied in this double-blind, randomized, cross-over trial. All subjects consumed four different sweetened beverages (600 mL/day) for 3 weeks each: medium fructose (MF) at 40 g/day, and high fructose (HF), high glucose (HG), and high sucrose (HS) each at 80 g/day. Euglycemic-hyperinsulinemic clamps with [6,6]-(2)H(2) glucose labeling were used to measure endogenous glucose production. Lipid profile, glucose, and insulin were measured in fasting samples.
RESULTS
Hepatic suppression of glucose production during the clamp was significantly lower after HF (59.4 ± 11.0%) than HG (70.3 ± 10.5%, P < 0.05), whereas fasting glucose, insulin, and C-peptide did not differ between the interventions. Compared with HG, LDL cholesterol and total cholesterol were significantly higher after MF, HF, and HS, and free fatty acids were significantly increased after MF, but not after the two other interventions (P < 0.05). Subjects' energy intake during the interventions did not differ significantly from baseline intake.
CONCLUSIONS
This study clearly shows that moderate amounts of fructose and sucrose significantly alter hepatic insulin sensitivity and lipid metabolism compared with similar amounts of glucose.