Each edition of GPA’s Prebiotic Spotlight focuses on a specific prebiotic type to raise awareness around the prebiotic itself, its sources, any notable and/or recent research, and how it is used in the marketplace. In this issue, resistant dextrin is highlighted.  

Overview 

Resistant dextrin (RD) is a glucose polysaccharide produced from corn, maize, wheat, or other edible starch through a heating and enzymatic treatment. During dextrinization, starch is degraded under the action of acid and heat, and new bonds, including β-1,6, β-1,2, α-1,6, and α-1,2 bonds are formed (Zhen et al., 2021). Only 15% of RD is enzymatically digested by the small intestine, meanwhile 75% reaches the colon and is slowly fermented, and the remaining 10% is excreted in the feces (Shamasbi et al., 2019).  

RD is often added to various food products, including beverages and baked goods to increase fiber content without significantly altering taste or texture. The RD used in a study by Aliasgharzadeh et al. (2014), NUTRIOSE® 06, is a purified RD glucose polymer (rich in α-1,4 and α-1,6 linkages) derived from wheat (NUTRIOSE®FB06) or maize (NUTRIOSE®FM06), which has shown to induce metabolic and health benefits via selective modulation of the human gut microflora. Specifically, RD is shown to modulate the gut microbiota by increasing Bacteroides species, decrease Clostridium perfringens, and produce several short chain fatty acids (SCFAs) (Thirion et al., 2022). RD additionally demonstrates protective effects on inflammation-induced disruptions of the intestinal barrier, thought to be due to increased acetate and propionate levels, and overall enrichment of SCFA-producing bacteria (Perreau et al., 2023). 

Benefit Areas 

Increasing research demonstrates the multitude of positive effects on various health markers from supplementation with RD. These include:  

• Supplementation with RD can be used to specifically increase P. distasonis in gut microbiota of healthy women. Further research is needed to confirm that P. distasonis directly modulates clinical effects observed in other studies. (Thirion et al., 2022)  

• Consumption of RD induces an adaptative response of gut microbiota towards fermentative pathways with lower gas production (Barber et al., 2022).  

• Supplementation of RD as a prebiotic in obese T2D women improved sleep and overall quality of life (Saleh-Ghadimi et al., 2022).  

• RD can modulate inflammation and improve insulin resistance in women with type 2 diabetes (T2D) (Aliasgharzadeh et al., 2014).  

• Supplementation with RD may improve the advanced glycation end-products, soluble receptor for advanced glycation-end products (sRAGE), and cardiometabolic risk factors in women with T2D (Farhangi et al., 2020).  

• RD supplementation modified satiety and glycaemic responses in healthy normal weight or overweight adults however further studies are required to determine long-term effects on body weight control and metabolic markers (Hobden et al., 2021). 

• Supplementation of RD in overweight men led to significant improvements in determinants of metabolic syndrome, lowered insulin resistance, and was found to be well tolerated (Li et al., 2010).  

• RD regulates metabolic parameters and androgen levels and manifestations, including hirsutism and menstrual cycle irregularity in women with polycystic ovary syndrome (PCOS) (Shamashi et al., 2019). 

• Ingestion of RD at breakfast decreased ghrelin concentrations in response to subsequent lunch, even when caloric load ingested at breakfast was lower (Nazare et al., 2011).  

• Consumption of RD led to significant decreased levels of cortisol and immune system related parameters, including lipopolysaccharide (LPS), Interferon-γ (IFN-γ), and interferon-γ/Interleukin-10 ratio (IFN-γ/IL10) (Farhangi et al., 2018).   

Sources 

The manufacture of RD, a specialty dextrin, is produced by partial hydrolyzation and subsequent repolymerization of a starch source that may include corn, maize, wheat, and other edible starches. This process produces an indigestible, mostly soluble dextrin with elevated fibre content, leaving RD available for bacterial fermentation (Saleh-Ghadimi et al., 2022). The product consists of polymers of glucose containing α(1-4) and α(1-6) glucosidic bonds, as well as various amounts of α/β(1-2), α/β(1-3), β(1-4) and β(1-6) bonds. RD has been accepted as a dietary fibre permitted for use by Health Canada’s Food Directorate as a novel fibre that provides energy yielding metabolites through colonic fermentation. In 2014, the European Food Safety Authority (EFSA) Panel on Dietetic Products, Nutrition and Allergies (NDA) provided a Scientific Opinion on the substantiation of health claims related to RD, concluding that RD is sufficiently characterized. The United States (US) Food and Drug Administration (FDA) has affirmed RD as Generally Recognized as Safe (GRAS), with no intake restrictions. In addition, RD meets the US FDA’s definition of dietary fibre as “naturally occurring fibres that are intrinsic and intact in plants, or as isolated or synthetic fibers that have demonstrated a beneficial physiological effect” (US FDA, 2018).  

Dose Range 

A study conducted by Marteau et al. (2011) assessed that RD is well tolerated, with no significant differences regarding symptoms between placebo group and the intervention group receiving 50 g/day of RD, divided into three doses. Additionally, NUTRIOSE®RD can constitute up to 20-25% of commercial food product’s composition without causing undesirable effects such as bloating and general discomfort (van den Heuvel et al., 2004). Additional studies suggest that 10 g/day of RD was sufficient to modulate immune system parameters, reduce inflammation and insulin resistance, and improve sleep and overall quality of life (Farhangi et al., 2018; Aliasgharzadeh et al., 2014; & Sahel-Ghadimi et al., 2022). A study by LeFranc-Millot et al. (2010) concluded that RD is effective in modulating satiety at doses from 8-14 g/day, and effective in aiding in weight loss at doses from 14 g/day. Thirion et al. (2022) demonstrated that an increase in P. distasonis in gut microbiota was induced by increasing doses of RD over 6 weeks from 5-20 g/day. 

Recent Research 

Currently, there are two studies on ClinicalTrials.gov proposing RD as a prebiotic to induce adaptive changes in metabolic activity of gut microbiota and colonic biomass in adults, and improve cognitive outcomes in older adults (ClinicalTrials.gov, 2024). Additionally, a third study on ClinicalTrials.gov (2024) proposes a fibre blend, including RD, to induce changes in systemic inflammation, dyslipidemia, and self-reported measures of mental health in individuals with metabolic syndrome. Moreover, searching of “resistant dextrin” on PubMed retrieved 35 results published in 2024 ranging from animal studies on T2D and insulin resistance to clinical trials on RD regarding weight loss and health markers in overweight children. 

A comparative study conducted by Liu et al. (2024) investigated the physicochemical properties and protective effects of hydrochloric acid-RD (H-RD), citric acid-RD (C-RD), and tartaric acid-RD (T-RD) on metabolic disorders and intestinal microbiota in T2D mice. Following a 4-week intervention period, hypoglycemic effects of either H-RD, C-RD, or T-RD oral supplementation, or metformin as a positive control were assessed. Additionally, changes in gut microbiota were measured using 16s rDNA analysis. For all the RD groups, body weight and fasting blood glucose improved significantly in T2D mice, followed by an accompanied reduction in serum indexes including triglycerides and low-density lipoprotein (LDL). Among the three RD intervention groups, T-RD showed the most significant improvement, followed by C-RD and H-RD. Oral administration of RD favoured the proliferation of specific gut microbiota, including Faecalibaculum, Parabacteroides, and Dubosiella, and reduced the ratio of Firmicutes/Bacteroidota. These findings suggest RD exhibits a remission effect on T2DM, and specifically reducing molecular weight and chain length of RDs may improve the hypoglycemic activity.  

An animal study conducted by Chen et al. (2024) assessed the effects of RD intervention on insulin resistance in Kunming mice. Over 8 weeks, changes in tissue weight, glucose-lipid metabolism levels, serum inflammation levels, and lesions of epididymal white adipose tissue (eWAT) were evaluated. Mice were allocated to a group of either normal diet, high-fat, high-sugar diet (HFHSD), HFHSD and 6.2 g/kg/d RD administered via gavage, or HFHSD and 0.2 g/kg/day metformin administered via gavage for the study period. The RD intervention led to significantly enhanced glucose homeostasis, reduced lipid metabolism, and reduced serum inflammation levels. RD intervention had a noticeable effect on the gene transcription profile of eWAT. Additionally, RD led to gut microbiota composition changes, with an increase in beneficial species such as Parabacteroides, Faecalibaculum, and Muribaculum, and a decrease in harmful bacteria such as Colidextribacter. These findings demonstrate the effectiveness of RD in alleviated insulin resistance, by reshaping the composition of gut microbiota.   

A randomized controlled clinical trial conducted by Slizewska et al. (2024) investigated the use of RD derived from potato starch as a potential additive in vegetable-fruit preparations that aid in weight loss and improve health markers. One-hundred overweight and obese children (aged 6-10) were randomized into a control group that consumed fruit and vegetable preparations twice daily, or an intervention group that consumed fruit and vegetable preparations with 10 g of added RD consumed twice daily, for a study period of 6 months. The RD group yielded favorable outcomes by increasing concentrations of SCFAs and branched-chain fatty acids (BCFAs) and enhanced fecal enzyme activities. These effects were found to last for an extended period of 3 months after discontinuing treatment. This study demonstrates that including RD into vegetable-fruit preparations enhances metabolic parameters in obese and overweight children.    

How is RD used in the marketplace? 

According to Business Research Insights (2024), global RD market size reached an estimated $382.9 million USD in 2022, and is projected to reach $752.64 million USD by 2031, with a compound annual growth rate (CAGR) of 7.8%. Key market drivers are attributed to increasing health awareness and demand for functional foods among consumers. Additionally, growing applications for RD in the healthcare and the supplement industry garners product demand. RD is extensively used in frozen food, dairy products, and cereals, as a prebiotic that can support gut health, and lead to a cascade of downstream beneficial health effects.