Polyphenol- and fibre-rich dried fruits with green tea attenuate starch-derived postprandial blood glucose and insulin: a randomised, controlled, single-blind, cross-over intervention
Abstract
Polyphenol- and fibre-rich foods (PFRF) have the potential to affect postprandial glycaemic responses by reducing glucose absorption, and thus decreasing the glycaemic response of foods when consumed together. A randomised, single-blind, cross-over study was conducted on sixteen healthy volunteers to test whether PFRF could attenuate postprandial blood glucose in healthy volunteers when added to a source of carbohydrate (starch in bread). This is the first study to examine the effects of a meal comprised of components to inhibit each stage of the biochemical pathway, leading up to the appearance of glucose in the blood. The volunteers were fasted and attended four visits: two control visits (bread, water, balancing sugars) and two test visits (single and double dose of PFRF) where they consumed bread, water and PFRF. Blood samples were collected at 0 (fasted), 15, 30, 45, 60, 90, 120, 150 and 180 min after consumption. The PFRF components were tested for α-amylase and α-glucosidase inhibitory potential in vitro. Plasma glucose was lower after consumption of both doses compared with controls: lower dose, change in mean incremental areas under the glucose curves (IAUC)=-27·4 (sd 7·5) %, P<0·001; higher dose, IAUC=-49·0 (sd 15·3) %, P<0·001; insulin IAUC was also attenuated by-46·9 (sd 13·4) %, P<0·01. Consistent with this, the polyphenol components of the PFRF inhibited α-amylase (green tea, strawberry, blackberry and blackcurrant) and α-glucosidase (green tea) activities in vitro. The PFRF have a pronounced and significant lowering effect on postprandial blood glucose and insulin response in humans, due in part to inhibition of α-amylase and α-glucosidase, as well as glucose transport.
多酚和富含纤维的食物(PFRF)有可能通过降低葡萄糖吸收来影响餐后血糖反应，从而降低食物一起食用时的血糖反应。研究人员对16名健康志愿者进行了一项随机、单盲、交叉研究，以测试在添加了碳水化合物(面包中的淀粉)的情况下，PFRF是否能降低健康志愿者餐后血糖。这是第一次对膳食成分的影响进行研究，这些成分可以抑制生化途径的每个阶段，从而导致血液中出现葡萄糖。志愿者被禁食并参加了四次访问:两次对照访问(面包、水、平衡糖)和两次测试访问(单剂量和双剂量PFRF)，他们吃面包、水和PFRF。分别于消费后0(禁食)、15、30、45、60、90、120、150和180 min采血。通过体外实验，测定其对α-淀粉酶和α-葡萄糖苷酶的抑制作用。与对照组相比，服用两种剂量后的血糖均较低:较低剂量，葡萄糖曲线下平均增量面积变化(IAUC)=-27·4 (sd 7·5)%，p。剂量越大，IAUC=-49·0 (sd 15·3)%，p;胰岛素IAUC也降低46·9 (sd 13·4)%，p·01。与此相一致的是，PFRF多酚组分在体外抑制α-淀粉酶(绿茶、草莓、黑莓和黑醋栗)和α-葡萄糖苷酶(绿茶)活性。PFRF对餐后血糖和胰岛素反应有显著的降低作用，部分原因是抑制α-淀粉酶和α-葡萄糖苷酶，以及葡萄糖转运。
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