JN：唾液中的酶有助于调节血糖

莫内尔中心科学家发表报告称：摄取淀粉后体内的血糖水平是由唾液淀粉酶调控的，唾液淀粉酶能够分解饮食中的淀粉成分。具体来说就是较高的唾液淀粉酶活性能降低血糖水平。

这项研究结果首次证明在淀粉消化过程中唾液淀粉酶的重要代谢作用，结果提示唾液淀粉酶可能有助于改善整体代谢状况。该研究特出之处在于计算含丰富淀粉食物的血糖指数以及最终患上糖尿病的风险。

论文主要作者、莫内尔营养科学家Abigail Mandel博士说：根据淀粉酶的水平，两个人食用相同淀粉类食品可能有明显不同的血糖水平。高淀粉酶水平的个人更好地适应淀粉食物，因为淀粉酶能迅速消化淀粉，同时保持血糖水平的平衡，淀粉酶含量低的人与此相反。因此，人们吃血糖指数的食物可能要考虑到他们的淀粉酶水平。

小麦、马铃薯、玉米、大米和其他谷物中的淀粉美是国饮食的重要组成部分，淀粉占我们机体热量来源的60％多。唾液中分泌的淀粉酶能将淀粉分解成简单的糖分子，以便将淀粉吸收入血液中的。因此需要一个最佳的淀粉酶活性范围以保持良好的健康的血糖水平。

先前的研究已经证明唾液淀粉酶活性高的人能够非常迅速降解淀粉。这一发现使得研究人员急需探知这一过程是如何促进机体消化淀粉和代谢葡萄糖的。

在这项发表在《营养学杂志》上的最新研究中，研究人员测定了48位健康成人唾液样本中淀粉酶的活性。基于唾液淀粉酶的活性，分成两大类：高淀粉酶（HA）和低淀粉酶（LA）。

每个个体食用简单的玉米淀粉溶液，研究人员在两个小时内抽取血液样本，并对样品进行分析以确定血糖水平和胰岛素浓度。结果发现摄取淀粉后，相对LA组，HA组的参与人员血糖水平降低了。这似乎与HA组的参与人员胰岛素的早期释放有关。

莫内尔感觉遗传学家、资深作家Paul Breslin博士表示：并非所有的人处理淀粉的能力是相同的。当消耗淀粉时，唾液淀粉酶水平较高的人能够保持更稳定的血糖水平，这最终可能会减轻胰岛素抵抗、减少非胰岛素依赖型糖尿病的风险。

该研究由国国立卫生研究院耳聋及其他交际障碍项目、国家糖尿病、消化、肾疾病研究所提供资金资助。Breslin是罗格斯大学营养科学系教授。（生物谷：Bioon）

doi:10.3945/jn.111.156984
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High Endogenous Salivary Amylase Activity Is Associated with Improved Glycemic Homeostasis following Starch Ingestion in Adults.

Abigail L. Mandel and Paul A. S. Breslin.

In the current study, we determined whether increased digestion of starch by high salivary amylase concentrations predicted postprandial blood glucose following starch ingestion. Healthy, nonobese individuals were prescreened for salivary amylase activity and classified as high (HA) or low amylase (LA) if their activity levels per minute fell 1 SD higher or lower than the group mean, respectively. Fasting HA (n = 7) and LA (n = 7) individuals participated in 2 sessions during which they ingested either a starch (experimental) or glucose solution (control) on separate days. Blood samples were collected before, during, and after the participants drank each solution. The samples were analyzed for plasma glucose and insulin concentrations as well as diploid AMY1 gene copy number. HA individuals had significantly more AMY1 gene copies within their genomes than did the LA individuals. We found that following starch ingestion, HA individuals had significantly lower postprandial blood glucose concentrations at 45, 60, and 75 min, as well as significantly lower AUC and peak blood glucose concentrations than the LA individuals. Plasma insulin concentrations in the HA group were significantly higher than baseline early in the testing session, whereas insulin concentrations in the LA group did not increase at this time. Following ingestion of the glucose solution, however, blood glucose and insulin concentrations did not differ between the groups. These observations are interpreted to suggest that HA individuals may be better adapted to ingest starches, whereas LA individuals may be at greater risk for insulin resistance and diabetes if chronically ingesting starch-rich diets.