Resistant Starch Research Update

Numerous studies have been released on resistant starch in recent months covering its role in various health conditions. Below we’ve shared an update on some of the more notable ones just published in 2022.

Effects of resistant starch interventions on metabolic biomarkers in pre-diabetes and diabetes adults.

Abstract: Simple lifestyle changes can prevent or delay the onset of type 2 diabetes mellitus (T2DM). In addition to maintaining a physically active way of life, the diet has become one of the bases in managing TD2M. Due to many studies linking the ability of resistant starch (RS) to a substantial role in enhancing the nutritional quality of food and disease prevention, the challenge of incorporating RS into the diet and increasing its intake remains. Therefore, we conducted this review to assess the potential benefits of RS on metabolic biomarkers in pre-diabetes and diabetes adults based on available intervention studies over the last decade. Based on the conducted review, we observed that RS intake correlates directly to minimize possible effects through different mechanisms for better control of pre-diabetic and diabetic conditions. In most studies, significant changes were evident in the postprandial glucose and insulin incremental area under the curve (iAUC). Comparative evaluation of RS consumption and control groups also showed differences with inflammatory markers such as TNF-α, IL-1β, MCP-1, and E-selectin. Only RS2 and RS3 were extensively investigated and widely reported among the five reported RS types. However, a proper comparison and conclusion are deemed inappropriate considering the variations observed with the study duration, sample size, subjects and their metabolic conditions, intervention doses, and the intervention base products. In conclusion, this result provides interesting insights into the potential use of RS as part of a sustainable diet in diabetes management and should be further explored in terms of the mechanism involved.

Key Takeaway: This review highlighted the pathways whereby RS2 and RS3 from high amylose corn, high amylose wheat, potatoes, green bananas, sorghum and others reduces the severity and exerts better control of the diabetic condition. Early evidence suggested benefits in inflammatory biomarkers such as TNF-alpha, IL-1beta, MCP-1 and E-selectin, but additional studies are needed to further identify the specific biochemical mechanisms and pathways. This review builds upon the 2016 FDA approved qualified health claim that resistant corn starch reduces the risk of type 2 diabetes. (  

Substitution of Refined Conventional Wheat Flour with Wheat High in Resistant Starch Modulates the Intestinal Microbiota and Fecal Metabolites in Healthy Adults: A Randomized, Controlled Trial.

Abstract: Background Resistant starch (RS) confers many health benefits, mostly through the microbial production of short chain fatty acids (SCFA), but foods containing appreciable RS are limited. High amylose wheat (HAW) is high in RS and lowers the glycemic response of foods, but whether it can improve gastrointestinal health measures is unknown.  Objective The objective of this study was to determine whether daily consumption of HAW food products improve markers of gastrointestinal health in healthy men and women compared to similar foods made from conventional wheat. Methods Eighty healthy adults (47 females and 33 males) were enrolled in a 4-arm parallel, randomized-controlled, double-blind trial. Following a 2-wk low dietary fiber run-in period, they were randomly allocated to one of four treatment groups: low amylose wheat-refined (LAW-R), LAW-wholemeal (LAW-W), HAW-refined (HAW-R) and HAW-wholemeal (HAW-W) and consumed bread (160g/d) and biscuits (75g/d) for 4-wk. Fecal biochemical markers were measured at baseline and 4-wk. Microbial abundance and diversity were quantified using 16S rRNA sequencing and perceived gut comfort by a semi-quantitative questionnaire completed at baseline, 2- and 4-wk. Results HAW showed similar effects on fecal output and total SCFA levels compared to LAW, but changes were observed in secondary measures for the refined treatment groups. At 4-wk, the HAW-R group had 38% higher fecal butyrate excretion compared to the LAW-R group (p<0.05), and higher fecal SCFA producing bacteria, Roseburia inulinivorans (p<0.001) compared to baseline. In comparison to baseline levels, LAW-R increased fecal p-cresol concentration, and fecal levels of a p-cresol producing bacteria, Clostridium from Peptostreptococcaceae family, but both were reduced by HAW-R. Amylose level did not affect measures of fecal consistency and was well tolerated without adversely affecting digestive comfort.  Conclusion Increasing RS intake of healthy adults by substituting refined conventional wheat with refined HAW modulates fecal metabolites and microbes associated with gastrointestinal health.

Key Takeaway: This CSIRO clinical study utilizes high amylose wheat, following the example of their earlier studies with high amylose cornstarch. Hundreds of studies have shown prebiotic benefits of high amylose cornstarch.



Nutrition, Immunology, and Kidney: Looking Beyond the Horizons.

Abstract: Purpose of Review Chronic kidney disease (CKD) is epidemic throughout the word. Despite various novel therapeutic opportunities, CKD is still associated with high morbidity and mortality. In CKD, patient’s chronic inflammation is frequent and related with adverse outcomes. Both innate and adaptive immunity are dysfunctional in CKD. Therefore, it is plausible to interfere with dysfunctional immunity in these patients. In the current review, we present the updated experimental and clinical data summarizing the effects of nutritional interventions including natural products and dietary supplements on immune dysfunction in the context of CKD. Recent Findings Nutritional interventions including natural products and dietary supplements (e.g., curcumin, sulforaphane, resistant starch, anthocyanin, chrysin, short chain fatty acids, fish oil resistant starch) slow down the inflammation by at least 6 mechanisms: (i) decrease nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB); (ii) decrease NLR family pyrin domain containing 3 (NLRP3); (iii) decrease interleukin-1 (IL-1), decrease interleukin-6 (IL-6) secretion; (iv) decrease polymorphonuclear priming); (v) promote anti-inflammatory pathways (nuclear factor-erythroid factor 2-related factor 2 (NFR2); (vi) increase T regulatory (Tregs) cells). Summary Natural products and dietary supplements may provide benefit in terms of kidney health. By modulation of nutritional intake, progression of CKD may be delayed.

Key Takeaways: This review included six resistant starch human clinical trials focusing on the impact of RS’s intestinal fermentation on kidney health. Although in its infancy, immune system modulation by nutritional intervention appears to be one of the promising strategies in the near future.

The potential roles of probiotics, resistant starch, and resistant proteins in ameliorating inflammation during aging (Inflammaging)

Abstract: Aging is typically accompanied by biological and physiological changes that alter cellular functions. Two of the most predominant phenomena in aging include chronic low-grade inflammation (inflammaging) and changes in the gut microbiota composition (dysbiosis). Although a direct causal relationship has not been established, many studies have reported significant reductions in inflammation during aging through well-maintained gut health and microbial balance. Prebiotics and probiotics are known to support gut health and can be easily incorporated into the daily diet. Unfortunately, few studies specifically focus on their significance in reducing inflammation during aging. Therefore, this review summarizes the scientific evidence of the potential roles of probiotics and two types of prebiotics, resistant starch and resistant proteins, in later age. Studies have demonstrated that the oral consumption of bacteria that may contribute to anti-inflammatory response, such as Bifidobacterium spp., Akkermansia munichipilla, and Faecalis praunitzii, contributes significantly to the suppression of pro-inflammatory markers in elderly humans and aged animals. Colonic fermentation of resistant starch and proteins also demonstrates anti-inflammatory activity owing to the production of butyrate and an improvement in the gut microbiota composition. Collectively, probiotics, resistant starch, and resistant proteins have the potential to promote healthy aging.

Key Takeaway: Multiple studies have demonstrated that resistant starch can abate aging-related chronic low-grade inflammation in humans and animal models. The main mechanisms include the direct increase of bacterial population, particularly bifidobacteria, A. Muciniphila, and F. prautnitzii and the supply of substrates for colonic microbial fermentation in the form of indigestible starch. All findings elaborated in this review are expected to trigger further exploration of resistant proteins, probiotics and resistant starch in maintaining gut health, targeting inflammaging, and promoting healthy aging.