2.2.1. Historic context glycemic index and glycemic load

One of the major dietary changes of the modern world has been the high consumption of processed foods rich in carbohydrates and low in fiber; highly related to the increasing rates of obesity and diabetes [49]. In this sense, pharmacological approaches focused on large clinical trials have been useful for improving glycemic control in patients with type 2 diabetes (DM2) [51]. Similarly, a positive effect in the control of diabetes has been associated with the consumption of diets low in GI [52], these indicator determines the effect of the available carbohydrates in food on the average concentration of glucose in blood, this value is defined as the relation between the area under the curve of 50 g of available carbohydrates in a food, with the area under the curve of same amount of carbohydrates of a reference food [53].

White bread and glucose, which has been assigned a GI of 100, are considered reference foods rather than a high value for this indicator [54]. Different entities worldwide, such as the American Diabetes Association (ADA) [55], the European Association for the Study of Diabetes [56], the Canadian Diabetes Association [57], and the UK Diabetes Nutrition Sub-Committee [58] have prioritized dietary treatment with a relevant approach to carbohydrate quality for the glycemic control, with special emphasis on reducing the digestion rate, absorption and metabolism of carbohydrates from foods [59].

Therefore, this indicator expresses the potential glycemia of a meal, representing the quality of foods with predominance of carbohydrates [60]. Foods with carbohydrates capable of digesting, absorbing and metabolizing quickly are considered food with high GI (GI ≥ 70 in the glucose scale). Those between GI = 55 and 70 are considered in an intermediate value, while those digested, absorbed and metabolized slowly are classified as foods with low GI (GI ≤ 55 in the glucose scale) [53, 60]. There are international tables with the published values of this indicator for a large number of products on the market. The first table was published in 1981 and was later updated in 1994 and 1995 [61, 62]. There is a marked controversy over the use of this indicator in the decade of the 80, due to an inadequate interpretation of the evidence for its determination [60, 63]. Criticism has focused on the methodological validity of the process to quantify it since a large number of factors had influenced the results [60, 64]. The position of the latest consensus of glycemic index experts in 925 held in Europe has determined that most of the current critics are not valid, and that these reflect a failure of the knowledge translation [60]. In this context, it is important to consider that important entities such as the International Diabetes Federation have recognized the relevance of post-prandial regulation of glucose in order to achieve the objectives of HBA1C by developing specific guidelines, whose management is related to the GI concept [64].

#### 2.2.2. Glycemic load, glycemic index, and insulin response

The value of glycemia and the insulin response depends on the quantity and quality of carbohydrate and the mix of food ingested, the so-called glycemic load (GL). The GL represents a relationship between the quantity and quality of carbohydrate [54, 60], and is defined as the total carbohydrate content available in an amount of food (GL = GI available carbohydrates/ specific amount of food) [60], and is the result of multiplying the amount of carbohydrate ingested in food by the value of its GI. The GL should be interpreted as a measure in the demand for insulin, this value is a good indicator of the levels of post-prandial glycemia, associated to the amount of calories in a particular portion of food or diet [65]. Thus, foods with high GL and high GI have a direct effect on the development of hyperinsulinemia [66], insulin resistance and risks to develop DM, which also have been linked to high-IG foods [67].

#### 2.2.3. Insulin response and inflammation mucus and glycocalyx layer

2.2. Low-glycemic index of carbohydrates and inflammatory state intestinal mucose

area under the curve of same amount of carbohydrates of a reference food [53].

One of the major dietary changes of the modern world has been the high consumption of processed foods rich in carbohydrates and low in fiber; highly related to the increasing rates of obesity and diabetes [49]. In this sense, pharmacological approaches focused on large clinical trials have been useful for improving glycemic control in patients with type 2 diabetes (DM2) [51]. Similarly, a positive effect in the control of diabetes has been associated with the consumption of diets low in GI [52], these indicator determines the effect of the available carbohydrates in food on the average concentration of glucose in blood, this value is defined as the relation between the area under the curve of 50 g of available carbohydrates in a food, with the

White bread and glucose, which has been assigned a GI of 100, are considered reference foods rather than a high value for this indicator [54]. Different entities worldwide, such as the American Diabetes Association (ADA) [55], the European Association for the Study of Diabetes [56], the Canadian Diabetes Association [57], and the UK Diabetes Nutrition Sub-Committee [58] have prioritized dietary treatment with a relevant approach to carbohydrate quality for the glycemic control, with special emphasis on reducing the digestion rate, absorp-

Therefore, this indicator expresses the potential glycemia of a meal, representing the quality of foods with predominance of carbohydrates [60]. Foods with carbohydrates capable of digesting, absorbing and metabolizing quickly are considered food with high GI (GI ≥ 70 in the glucose scale). Those between GI = 55 and 70 are considered in an intermediate value, while those digested, absorbed and metabolized slowly are classified as foods with low GI (GI ≤ 55 in the glucose scale) [53, 60]. There are international tables with the published values of this indicator for a large number of products on the market. The first table was published in 1981 and was later updated in 1994 and 1995 [61, 62]. There is a marked controversy over the use of this indicator in the decade of the 80, due to an inadequate interpretation of the evidence for its determination [60, 63]. Criticism has focused on the methodological validity of the process to quantify it since a large number of factors had influenced the results [60, 64]. The position of the latest consensus of glycemic index experts in 925 held in Europe has determined that most of the current critics are not valid, and that these reflect a failure of the knowledge translation [60]. In this context, it is important to consider that important entities such as the International Diabetes Federation have recognized the relevance of post-prandial regulation of glucose in order to achieve the objectives of HBA1C by developing specific guidelines, whose manage-

The value of glycemia and the insulin response depends on the quantity and quality of carbohydrate and the mix of food ingested, the so-called glycemic load (GL). The GL represents a relationship between the quantity and quality of carbohydrate [54, 60], and is defined as the total carbohydrate content available in an amount of food (GL = GI available carbohydrates/ specific amount of food) [60], and is the result of multiplying the amount of carbohydrate

2.2.1. Historic context glycemic index and glycemic load

188 Diabetes Food Plan

tion and metabolism of carbohydrates from foods [59].

ment is related to the GI concept [64].

2.2.2. Glycemic load, glycemic index, and insulin response

Several studies have determined a clear link between the glycemic index and the glycemic load of food and the insulin response [52, 68, 69]. Studies suggest that carbohydrates can modify the microbiota, depending on their ability to increase glycemic and insulin response values according to glycemic and insulinemic index [70, 71]. In this sense, several studies in rodents have reported oligofructose as a recognized prebiotic, capable of modulating IM and improving insulin sensitivity [72, 73]. Similarly, inulin-type fructans have been tested to determine their ability to modulate lipid metabolism and carbohydrate in various animal models [73, 74]. It has been reported that oligofructose (OFS) decreases the intake of food, the development of fat mass and hepatic steatosis in normal and obese rodents. In addition, OFS exerts an antidiabetic effect in rats treated with streptozotocin and mice treated with high content of fat [72]. Chang et al. demonstrated that the addition of OFS also caused changes in the IM, specifically for Bifidobacterium and Clostridium leptum [75] content. These results suggest that OFS may be an effective therapeutic complement in the treatment of diabetes type 1 (DM1) by improving insulin sensitivity and beta cell function, leading to better glycemic control [76]. OFS reduced body weight, energy intake and fat mass in both phenotypes (P < 0.05) [76]. In another study carried out in two different groups of rodents, OFS did not modify ghrelin in plasma, but plasma levels of GIP were reduced and PYY were elevated (P < 0.05) [76] by OFS, reducing body weight and adiposity in prone obese phenotypes and in those insulin-resistant [76].

The changes induced by this saccharide in the profiles of IM of these animals, along with the changes of intestinal hormone levels probably contribute to lower body weights sustained [76, 77]. Milk prebiotic oligosaccharides have been reported to alter the IM and may influence the metabolism of the host. In a study performed in rats comparing diets with 15% of glucose, fructose, galactose, and methylcellulose content, daily intake of 15% galactose improved the sensitivity to hepatic insulin compared with glucose and fructose, producing an increase in the content of hepatic glycogen in the feeding state and a positive change in the IM populations; unlike the intake of galacto-oligosaccharides [78], which improved the IM profile without any effect on the insulin sensitivity. The GI of lactose, fructose and isomaltose is (=43), (=20), and (=2), respectively [62]. Further studies on these indicators are required in monosaccharides and their effect on the human microbiome.
