Improved glycaemic response and attenuated post-prandial sugar-induced endothelial dysfunction by polyphenol-rich foods

英国广播公司今年(2014年6月10日)的一则新闻标题称，“英格兰三分之一的成年人‘处于’糖尿病边缘‘”。饮食(加上运动)在许多疾病中都起着作用，但对于2型糖尿病来说，这几乎是唯一的危险因素。富含糖分的食物也登上了新闻头条，这一领域充满了争议。高糖食品受到了负面报道，但却受到了消费者的欢迎。糖替代品有一些问题，这些问题往往会改变食品的性质。人工甜味剂有令人不快的回味，没有糖的口感或感官特性。一些公司和消费者寻求减糖，但很难实现。在这里，我们建议也许可以保持血糖水平，但使用多酚来钝化餐后立即出现的血糖峰值。这也将有助于减少糖但不能完全取代糖的情况。我们将重点研究多酚，这是一组天然存在于水果、蔬菜、茶、咖啡和可可中的成分。我们将确定添加来自多酚丰富食物补充剂或提取物等来源的多酚是否能够通过两种方式降低患糖尿病的风险：通过钝化高糖餐后出现的血糖峰值；还通过帮助保护血管壁上的细胞-内皮细胞的健康。存在一种综合作用的可能性，因为血糖峰值也会损害这些血管壁，因此多酚被认为既可以通过降低餐后血糖水平间接发挥作用，也可以直接作用于内皮细胞，通过各种生化机制提供保护。首先，我们将评估哪种多酚是最好的，通过检测它们抑制葡萄糖从食物进入血液的过程的能力。这些分析可以相当迅速地对数十种不同的多酚进行检测。我们还将培养培养的血管细胞，并测试哪种多酚最能保护这些细胞免受高糖的破坏。这些重要的实验将使我们能够确定用于人体研究的最佳多酚。虽然在这一领域已经有了一些知识，但我们已经改进了一些检测方法，并认为有必要确保我们拥有最好的多酚。然后，我们将使用数据库选择最好的多酚，并选择用于人体研究的食物。在这项研究中，我们将让志愿者摄入碳水化合物，如面包和糖中的淀粉，并确定富含多酚的食物是否会抑制餐后血糖峰值。同时，我们将使用一种非侵入性的技术来测量血管壁的健康状况。这些实验将向我们展示，志愿者体内的多酚是否可以改善血管健康，并抑制血糖峰值。我们还将在患有代谢综合征的人身上进行测试，这些人超重程度更高，血糖水平永久较高(但他们的血糖水平低于糖尿病患者)。为了确定其机制，我们将进行两种类型的实验。第一种方法是从正在接受手术的人身上提取细胞，用应激和多酚处理这些细胞，看看是否有任何保护作用。这些细胞代表了我们目前在体外实验室实验中最大的努力，以模拟人体内发生的事情。我们还将测试哪些单独的食物在钝化血糖峰值方面是有效的，但只使用健康的正常体重志愿者。所有这些都不会导致索赔本身，但它将为潜在的申请打开大门，从而导致索赔或一系列索赔。食品工业将受益于管理代谢综合征和降低患2型糖尿病风险的潜在成分，以及未来衡量这些成分影响的策略。公众将受益于改善他们的糖代谢和处理能力的食物，从而降低糖尿病风险。

A BBC news headline this year (10th June 2014) stated "One in three adults in England 'on cusp' of diabetes". Diet (with exercise) plays a role in many diseases, but for type 2 diabetes, it is almost the only risk factor. Sugar-rich foods are also in the headlines, and the area is full of controversy. High sugar foods have received bad press, but are popular with the consumer. Sugar replacers have some problems, and these often change the food properties. Artificial sweeteners have undesirable aftertastes and provide none of the mouth-feel or sensory properties of sugar. Sugar reduction is sought by some companies and consumers, but is difficult to achieve. Here we suggest that it may be possible to retain sugar levels but use polyphenols to blunt the immediate sugar spike after a meal. This would also assist where sugar is reduced but not completely replaced. We will focus on polyphenols, a group of naturally occurring components of fruits, vegetables, tea, coffee and cocoa.We will determine if either adding polyphenols from sources such as polyphenol rich foods supplements or extracts are able to reduce the risk of developing diabetes in two ways: by blunting the sugar-spikes seen after consumption of a high sugar meal; and also by helping to preserve the health of the cells lining the blood vessel walls - the endothelial cells. There is the possibility of a combined effect, since the sugar spikes also damage these blood vessel walls, and hence polyphenols are proposed to act both indirectly by decreasing the after-meal sugar levels, and also by acting directly on the endothelial cells to give protection by various biochemical mechanisms. Firstly we will assess which polyphenols are best, using assays to measure their ability to inhibit the processes involved in getting glucose into the blood from the food. These assays can be performed quite rapidly on tens of different polyphenols. We will also grow cultured blood vessel cells and test which polyphenols are best at protecting these cells from the damaging effects of high glucose. These important experiments will allow us to determine the best polyphenols for the human study. Although there is already some knowledge in this area, we have improved some of the assays and feel it is necessary to be sure we have the best polyphenols.We will then choose the best polyphenols using a database and select the foods for the human study. In this study, we will ask volunteers to consume carbohydrates, as starch in bread and sugar, and determine if the polyphenol rich foods dampen down the after-meal sugar spikes. In parallel, we will measure the health of the blood vessel wall using a technique which is non-invasive. These experiments will show us whether polyphenols in volunteers can improve blood vessel health as well as dampen glucose spikes. We will also test this in people with metabolic syndrome, who are more overweight and have permanently higher blood sugar levels (but whose levels are lower than in diabetic patients).To determine the mechanisms, we will perform two types of experiment. The first is to take cells from people who are undergoing an operation and treat these cells with stresses and polyphenols to see if there is any protective effect. These cells represent our best effort currently for in vitro lab experiments to mimic what is going on in the human body. We will also test which of the individual foods are active in blunting the sugar spikes, but just using healthy normal weight volunteers.All of this will not lead to a claim itself, but it will open the door for potential applications leading to claims or series of claims. The food industry will benefit from potential ingredients to manage metabolic syndrome and reduce the risk of developing type 2 diabetes, and strategies to measure such effects of ingredients in the future. The public will benefit from access to foods which improve their sugar metabolism and handling, and so decrease diabetes risk.