Home Medizin Die Forschung untersucht die gesundheitlichen Vorteile resistenter Stärke in pflanzlichen Diäten

Die Forschung untersucht die gesundheitlichen Vorteile resistenter Stärke in pflanzlichen Diäten

von NFI Redaktion

In a recent review published in the journal Boundaries in Nutrition, a group of authors examined the health benefits of resistant starch (RS). They evaluated the impact of food processing methods on its presence in plant-based foods based on clinical insights and observational studies from 2010 to 2023.

Study: Harnessing the Power of Resistant Starch: A Narrative Overview of its Health Effects and Processing Challenges. Image credit: Adao / Shutterstock



Background

Carbohydrates (CHO) are essential for energy and glucose regulation in the diet, with starch being a major source in grains, fruits, vegetables, and legumes. Starches vary in digestibility, from fast to slow-digesting forms, while RS evades digestion and benefits gut health similarly to fibers. Despite dietary recommendations promoting minimal daily fiber intake to reduce the risk of chronic diseases, actual consumption often falls below recommended levels in various regions. Current worldwide RS intake is low, indicating a significant nutritional gap. This underscores the urgent need for research on food processing techniques that can maintain or increase RS content with the aim of more effectively utilizing its health benefits.

Exploring the Benefits and Production of RS

Due to its potential health benefits and the challenges associated with preserving its content through food processing, RS is a key focus in nutritional science. This review begins with an in-depth examination based on a literature search in the databases Medline, COCHRANE, and The Lens. RS varies in form and function, divided into five types, each with unique characteristics and sources. For example, resistant starch Type 1 (RS1) is found in whole or partially milled grains and seeds and resists digestion due to physical encapsulation. Resistant starch Type 2 (RS2) is naturally present in foods like uncooked potatoes and green bananas and is protected by its granular structure. Resistant starch Type 3 (RS3) or retrograded starch occurs when cooked starchy foods cool, rendering them indigestible to enzymes. Resistant starch Type 4 (RS4) is a chemically modified product designed to resist digestion. The category of resistant starch (RS5), originally defined for starch-lipid complexes, has been expanded to include additional resistant complexes formed with molecules like amino acids and polyphenols.

The Impact of Food Processing on RS

The nutritional value of RS, especially its low glycemic index and satiating properties, can be significantly influenced by food processing methods. For example, the RS content in foods can be influenced at various stages, from the type of crop cultivated to methods of cooking, cooling, and storing the foods. Breeding techniques that increase the amylose content of starches can lead to higher RS content post-cooking. However, milling can decrease the RS content by disrupting the crystalline structure of starch. Similarly, cooking methods that require high temperatures can lower RS content, whereas cooling and storage processes can reduce starch and increase RS content.

Breeding for Increased RS Content

Breeding techniques focusing on a higher ratio of amylose to amylopectin can significantly increase RS content in foods. For example, wheat varieties with high amylose content have shown a promising increase in RS content in bread, resulting in notable health benefits like improved postprandial glycemia. However, there are trade-offs, as high amylose content varieties can compromise the texture quality of dough and bread products.

Effects of Grinding and Cooking

Grinding processes, especially those that disrupt the crystalline structure of starch, can reduce RS content, with whole grains generally exhibiting higher RS values. Cooking methods, including microwave and heat-moisture treatments, have a significant impact on RS content. For example, microwave cooking can increase RS levels, likely due to its unique heating method that favors starch retrogradation. Additionally, carefully controlling the starch-moisture ratio as well as the duration and temperature of heating can further optimize RS content.

Cooling, Storage, and Fermentation Effects

Cooling post-cooking and subsequent storage have a significant impact on RS content, with cooling post-cooking significantly increasing RS content in foods like rice and bread. The type of storage, whether at room temperature, chilled, or frozen, plays a crucial role. Fermentation conditions also significantly influence RS content; for example, sourdough fermentation with specific microbial strains can increase RS content in bread. Such fermentation strategies, alongside optimal storage conditions, provide practical ways to increase RS content in foods, contributing to the broader goal of improving fiber intake and related health benefits.

Clinical Evidence of the Health Effects of RS

The review addresses the clinical evidence evaluating the effects of RS on health outcomes, including gastrointestinal health, metabolic responses, and inflammation markers. RS intake has been associated with several health benefits, such as improved stool quality, reduced glycemic response, and a favorable impact on gut microbiota. Moreover, RS consumption has been linked to lower inflammation levels and enhanced antioxidant capacity.

Conclusions and Future Directions

This narrative overview underscores the significant health benefits of RS and the complex interplay between food processing methods and RS content. It highlights the need for further research to optimize processing techniques to enhance the bioavailability of RS and ultimately contribute to better health outcomes. Understanding the mechanisms behind the health benefits of RS and the influence of food processing can guide the development of dietary recommendations and RS-rich foods, paving the way for improved public health strategies.

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