ENDO 2015：多吃洋葱有益，改善血糖及胆固醇

近日，在圣地亚哥举办的第97届美国内分泌学会会议上，来自德尔塔州立大学的研究人员通过研究表示，当同抗糖尿病药物二甲双胍结合时，洋葱提取物可以明显降低患糖尿病大鼠的血压并及总胆固醇水平。

研究者Anthony Ojieh说道，洋葱非常便宜而且容易获得，其通常用作营养补充剂，而其对治疗糖尿病却有潜在的用途；研究人员将药物性诱导的糖尿病大鼠分为三组，分别每日给予二甲双胍加上不同剂量的洋葱提取物200mg/kg、400 mg/kg及600 mg/kg，来观察是否这种结合方式会增强药物的效果；同时研究人员奖正常血糖的非糖尿病大鼠分为三组，分别喂食二甲双胍及洋葱提取物来作为对照进行研究，同时研究人员设置了两个控制组，即一个非糖尿病组及一个糖尿病组，这两组的小鼠既不接受二甲双胍也不接受洋葱提取物，上述每组为5个大鼠。

结果发现，两个剂量：400 mg/kg及600 mg/kg的洋葱提取物可以明显快速降低糖尿病大鼠的血糖水平，比例分别为50%和35%（相比基准水平）；有报道称洋葱可以降低糖尿病大鼠的总胆固醇水平，而研究发现上述两个剂量在降胆固醇上会带来极大的效应；但研究者发现洋葱提取物可以增加非糖尿病大鼠的平均体重，而对糖尿病大鼠则没有影响。

研究者表示，洋葱的热量不高，然而其似乎会增加大鼠的代谢比率，从而增加其食欲进而引发大鼠摄食增加；对来自每一个糖尿病大鼠所移除的胰腺进行组织学检查，结果显示不管是二甲双胍还是洋葱提取物都不会治愈药物引发的大鼠机体损伤；最后研究者Ojieh说道，我们需要更为深入的研究来解释洋葱降低血糖的分子机制，用作实验的洋葱提取物是一种来自洋葱茎部的粗提物，如果其可以应用于人类机制，那么研究人员将会对其进行提纯以便获得有效成分可以更加有效足量的进行人类机体的临床试验。

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"Onion is cheap and available and has been used as a nutritional supplement," said lead investigator Anthony Ojieh, MBBS (MD), MSc, of Delta State University in Abraka, Nigeria. "It has the potential for use in treating patients with diabetes."

To three groups of rats with medically induced diabetes, Ojieh and his colleagues gave metformin and varying doses of onion extract--200, 400 and 600 milligrams per kilograms of body weight daily (mg/kg/day)--to see if it would enhance the drug's effects. They also gave metformin and onion extract to three groups of nondiabetic rats with normal blood sugar, for comparison. Two control groups, one nondiabetic and one diabetic, received neither metformin nor onion extract. Another two groups (one with diabetes, one without) received only metformin and no onion extract. Each group contained five rats.

Two doses of onion extract, 400 and 600 mg/kg/day, strongly reduced fasting blood sugar levels in diabetic rats by 50 percent and 35 percent, respectively, compared with "baseline" levels at the start of the study before the rodents received onion extract, Ojieh reported.

Allium cepa also reportedly lowered the total cholesterol level in diabetic rats, with the two larger doses again having the greatest effects.

Onion extract led to an increase in average weight among nondiabetic rats but not diabetic rats.

"Onion is not high in calories," Ojieh said. "However, it seems to increase the metabolic rate and, with that, to increase the appetite, leading to an increase in feeding."......