低聚果糖和其他低聚糖

低聚果糖和其他低聚糖

低聚果糖和其他低聚糖的功能

低聚糖是一类短链的糖（“低聚”指“少”）。低聚果糖和菊粉在许多蔬菜中含有，由短链的果糖分子组成。低聚半乳糖也天然存在，由短链的半乳糖分子组成。这些化合物只能被人类部分消化。^{[1 2 3 4]}摄入低聚糖时，不能消化的部分可作为益生菌的食物，如双歧杆菌和乳杆菌。

临床试验发现低聚果糖、低聚半乳糖或菊粉可以提高这些益生菌在肠道内的数量同时减少有害菌的数量。^{[5 6 7 8 9]}它们的其他益处还包括提高有益的短链脂肪酸如丁酸酯的生成、提高钙和镁的吸收以及加快对毒性物质的清除。^{[10 11]}

因为低聚果糖、低聚半乳糖和菊粉可以提高肠道功能和提高益生菌的数量，有人建议将这些物质用于缓解肠易激综合征症状。可是，一项双盲实验发现低聚果糖（每天3次服用2克）并未发现具有效果。^[12]动物实验研究发现低聚果糖可以降低糖尿病的血糖水平以及降低血胆固醇和甘油三酯水平。^[13]在一项对血脂升高的中年男性和女性进行的双盲实验中发现，菊粉（每天服用10克，维持8周）可以明显降低快速血糖水平以及2型糖尿病病人的血清胆固醇水平。^{[14 15]}可是，在另一项试验中，患有2型糖尿病的人补充低聚果糖（每天15克）维持20天却不能有效降低血糖或血脂。^[16]另外，对健康成人的双盲实验也发现补充低聚果糖或低聚半乳糖8周后对血糖水平、胰岛素分泌或血脂水平没有任何作用。^{[17 18]}因为这些矛盾，目前还需更多的研究来进一步证实。

许多双盲实验正对低聚果糖或菊粉降低血胆固醇和甘油三酯水平的能力进行研究。这些试验发现患有血胆固醇或甘油三酯升高的人，包括那些2型糖尿病患者，给予低聚果糖或菊粉（每天8~20克）可以明显降低血甘油三酯水平，但对于胆固醇的作用却不稳定。^{[19 20 21 22]}对于正常人或血胆固醇、甘油三酯水平较低的人，低聚果糖或菊粉却没有太多的作用。^{[23 24 25]}

低聚果糖和其他低聚糖的分布

低聚果糖和菊粉天然存在于菊芋、牛蒡、菊苣、韭菜、洋葱和芦笋中。低聚果糖补充剂由菊苣根中提取出来。^[26]而菊粉分布于水果、蔬菜和作为配料的植物。^[27]实际上，菊粉是日常饮食的重要组成部分。低聚果糖还可以通过黑曲霉菌中的酶作用于蔗糖而合成。^[28]低聚半乳糖天然存在与大豆中，也可通过乳糖合成。低聚果糖、低聚半乳糖和菊粉制成胶囊、片剂和粉剂也有效。

低聚果糖、低聚半乳糖和菊粉已经被应用于与以下疾病的治疗中。（以下所有信息适用于个体化健康情况）：

哪些人可能会缺乏？

因为葡甘聚它们不是必需营养素，所以不会缺乏。

一般需要多少？

美国人每天摄入的低聚糖的量大约是800~1000毫克。对于提高益生菌的数量，平均的推荐量为每天2000~3000毫克。在糖尿病和高脂血症的病人的试验中，每天的剂量大约是8~20克。

是否有副作用和药物相互作用？

一般情况下，低聚糖的耐受性很好。有报道称会出现腹胀症状。摄入较高的量时（每天40克），低聚果糖和其他低聚糖会引起腹泻。

有一例个案报道了一位39岁男性摄入较高剂量的菊粉后出现了威胁生命的过敏反应。对菊粉的过敏反应在实验室中也得到了证实。^[29]但这种过敏很罕见。证实对菊粉过敏的人不用服用低聚果糖。

到目前为止，还不清楚低聚糖与其他药物之间的相互作用关系。

参考文献

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