Effect of resistant starch on glycemic ındex and glycemic control

Abstract

The contemporary pursuit of health-conscious dietary choices has spurred a growing demand for functional foods enriched with nutritional and health-promoting attributes. The food industry, in response, is increasingly dedicated to the development of innovative products aligned with health objectives (1). Resistant starch (RS), an emerging ingredient, has garnered substantial attention due to its potential in the production of health-oriented commercial foods (2). Over the years, the market has witnessed the introduction of commercial foods fortified with type 2 and type 3 resistant starch, followed by the emergence of cost-effective type 4 resistant starch ingredients for dietary fiber supplementation (3). No suggestions have been made for daily intake of resistant starch or for the resistant starch content of products on the food industry. The variation of resistant starch throughout cooking, cooling and ripening conditions is known as one of the reasons for this situation. In developing countries, resistant starch intake is known to vary between 30-40 grams per day, but it also depends on other factors of the daily pattern of nutrition, such as the food groups of choice (4). The evolving concept of prebiotics, substances selectively beneficial to host microorganisms conferring health advantages, has propelled the spotlight onto resistant starch. With its recognition, RS has emerged as a non-glycemic source of dietary fiber that could potentially mitigate diet-related non-communicable diseases, including obesity, diabetes, cardiovascular disease, metabolic syndrome, and colon cancer (5). The realm of beneficial applications for enzyme-resistant starch extends beyond its nutritional value, encompassing domains like diabetes, obesity, colon cancer, immune system disorders, diverse cancer types, and cardiovascular ailments. In 2011, the European Food Safety Authority (EFSA) validated health claims for RS, endorsing specific proportions of enzyme-resistant starch in carbohydrate-rich bakery products for the regulation of postprandial blood glucose and insulin levels (6). Functional foods, proposed as adjunctive aids for enhancing glycemic control in type 2 diabetes, hold potential to alleviate the significant economic burden associated with this disease, which has been estimated as 825 billion $ in related health services as of 2014 (7). The EFSA's assertion that substituting digestible starch with resistant starch can attenuate postprandial blood glucose fluctuations and the U.S. Food and Drug Administration's (FDA) assertion of reduced type 2 diabetes risk with high amylose, corn-derived RS further underscore the promising prospects of RS consumption (8). Strong corroboration exists between RS consumption and favorable outcomes on gut health, inflammatory markers, insulin response, and lipid metabolism (9). The taxonomy of RS comprises distinct categories each characterized by unique physicochemical attributes. Type 1 RS, physically shielded from digestion by binding to fibrous cell walls or residing within protein matrices and thick cell walls, is commonly found in partially or fully milled rice, cereals, and legumes (5,10,11). Type 2 RS, organized in a tightly packed radial configuration within raw starch granules, evades gelatinization and digestion due to its inaccessible granular structure. In the natural crystal forms B and C, this variant exhibits a relatively dehydrated compact crystal structure and is prevalent in high-amylose cereals, raw potatoes, green bananas, and select legumes (5,8,10,11). Type 3 RS emerges through the cooking and subsequent cooling of starch-rich foods, leading to gelatinization. Culinary examples rich in type 3 resistant starch encompass cooked and cooled potatoes, rice, pasta, bread, and specific maize varieties (12). Additionally, triticale, rye, buckwheat, chickpeas, kidney beans, peas, broad beans, and lentils constitute natural sources of type 3 RS (13). Type 4 RS entails modified molecular structures, augmenting its resistance to amylase. This variant undergoes chemical or enzymatic modifications, often incorporating external additives like lipids, sugar alcohols, and sugars, resulting in cross-links and novel chemical bonds through processes like substitution, esterification, or cross-linking. Type 5 RS represents an emerging category forming amylose and lipid complexes, along with thermostable starch-lipid complexes during gelatinization. Typically derived from high-amylose starch cereals, type 5 RS holds considerable potential (5,10,11). The physiological impact of RS's digestion rate is well-established, particularly due to its role in reducing postprandial glycemic responses in diverse populations; including healthy, overweight or obese adults, as well as those at risk for type 2 diabetes. Consequently, the substitution of digestible starch with RS yields beneficial glycemic effects among both healthy individuals and those with prediabetes (14). Glycemic variability entails acute glycemic fluctuations linked to oxidative stress-induced cellular damage. The crucial role of dietary carbohydrate quality in stabilizing glucose absorption and modulating postprandial glycemic responses is recognized (15). Research suggests that substituting dietary carbohydrates with specific fiber types like RS in food formulations reduces postprandial blood glucose levels. This effect is notable when RS replaces refined wheat flour in product compositions, indicating potential for lowering blood glucose levels (16). Similarly, the moderated digestion and absorption resulting from consumption of RS-rich rice-based foods are proposed to regulate type 2 diabetes by attenuating postprandial glucose and insulin responses (17). High-amylose corn-derived type 2 RS has shown efficacy in reducing glycemic response, including postprandial glucose and insulin levels (8). Empirical investigations have yielded diverse outcomes pertaining to the impact of RS. Investigations have generally focused on glycemic control and glycemic variability, glycemic and insulinemic response, glycemic index and glycemic load, but they have also focused on factors such as insulin resistance, serum lipoproteins, HbA1c and inflammatory markers. Evidentiary support suggests that RS contributes to the reduction of postprandial blood glucose and insulin responses, fostering enhanced glycemic control, while also facilitating the transformation of foods into low glycemic index products. Moreover, it stimulates fermentation processes, exerts appetite-suppressing effects, and engenders diminished desires to consume; resulting in reduction in inflammatory markers. However, it is pertinent to acknowledge studies wherein no discernible effects were observed. RS's potential as a functional element for disease prevention, treatment, and enhancing well-being in healthy individuals is notable. This review article is devoted to accentuating the impact of RS on glycemic index and glycemic control, meticulously scrutinizing relevant national and international literature, mainly spanning the preceding seven years. This review article is also devoted to evaluating the role of resistant starch as a health-promoting and health-enhancing factor in the context of glycemic index and glycemic control.