Resistant Starch Content in Foods Commonly Consumed in the United States: A Narrative Review

Technological and Nutritional Aspects of Bread Production: An Overview of Current Status and Future Challenges

Bakery products, especially bread, exist in many homes worldwide. One of the main reasons for its high consumption is that the main raw material is wheat, a cereal that can adapt to a wide variety of soils and climates. However, the nutritional quality of this raw material decreases during its industrial processing, decreasing the value of fibers, proteins, and minerals. Therefore, bread has become a product of high interest to increase its nutritional value. Due to the high consumption of bread, this paper provides a general description of the physicochemical and rheological changes of the dough, as well as the sensory properties of bread by incorporating alternative flours such as beans, lentils, and soy (among others). The reviewed data show that alternative flours can improve fiber, macro, and micronutrient content. The high fiber content reduces the quality of the texture of the products. However, new processing steps or cooking protocols, namely flour proportions, temperature, cooking, and fermentation time, can allow adjusting production variables and optimization to potentially overcome the decrease in sensory quality and preserve consumer acceptance.

Structural analysis of type 3 resistant starch from Canna edulis during in vitro simulated digestion and its post-digested residue impact on human gut microbiota

Introduction

Resistant starch (RS) has garnered attention for its health benefits, including modulating the gut microbiota and promoting the production of short-chain fatty acids (SCFAs).

Methods

This study investigates structural changes of type 3 resistant starch from Canna edulis (CE) during in vitro simulated digestion and explores its health-relevant properties using healthy individuals' fecal microbiota.

Results

CE, prepared with a RS content of 59.38%, underwent a comprehensive analysis employing X-ray diffraction (XRD), fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). During simulated digestion, XRD analysis demonstrated a significant rise in CE's relative crystallinity from 38.92 to 49.34%. SEM illustrated the transition of CE from a smooth to a rough surface, a notable morphological shift. Post-digestion, CE was introduced into microbial fermentation. Notably, propionic acid and valeric acid levels significantly increased compared to the control group. Furthere more, beneficial Bifidobacterium proliferated while pathogenic Escherichia-Shigella was suppressed. When comparing CE to the well-known functional food fructo-oligosaccharide (FOS), CE showed a specific ability to support the growth of Bifidobacterium and stimulate the production of short-chain fatty acids (SCFAs) without causing lactic acid accumulation.

Discussion

CE demonstrates potential as a functional health food, with implications for gut health enhancement and SCFAs production.

Production of Resistant Starch by Roasting Retrograded Starch with Glucose

Starch is a natural plant raw material applicable in many areas of industry. In practice, it is most often used in a modified form, i.e., after various treatments aimed at modifying its properties. Modifications of native starch enable producing resistant starch, which, as a prebiotic with confirmed health-promoting properties, has been increasingly used as a food additive. The present study aimed to determine the effect of roasting retrograded starch with the addition of anhydrous glucose at different temperatures (110, 130 or 150 °C) and different times (5 or 24 h) on the modified starch's properties. The results of high-performance size-exclusion chromatography coupled with refractive index detector (HPSEC/RI) analysis and the changes observed in the solubility of starch roasted with glucose in DMSO, as well as in its other properties, confirm the changes in its molecular structure, including thermolytic degradation and the ongoing polymerization of starch with added glucose.

Structural characteristics and biological activities of polysaccharides from barley: a review

Barley (Hordeum vulgare L.) is rich in starch and non-starch polysaccharides (NSPs), especially β-glucan and arabinoxylan. Genotypes and isolation methods may affect their structural characteristics, properties and biological activities. The structure-activity relationships of NSPs in barley have not been paid much attention. This review summarizes the extraction methods, structural characteristics and physicochemical properties of barley polysaccharides. Moreover, the roles of barley β-glucan and arabinoxylan in the immune system, glucose metabolism, regulation of lipid metabolism and absorption of mineral elements are summarized. This review may help in the development of functional products in barley.

Harnessing the power of resistant starch: a narrative review of its health impact and processing challenges

Starch is a primary energy storage for plants, making it an essential component of many plant-based foods consumed today. Resistant starch (RS) refers to those starch fractions that escape digestion in the small intestine and reach the colon where they are fermented by the microflora. RS has been repeatedly reported as having benefits on health, but ensuring that its content remains in food processing may be challenging. The present work focuses on the impact RS on health and explores the different processes that may influence its presence in foods, thus potentially interfering with these effects. Clinical evidence published from 2010 to 2023 and studying the effect of RS on health parameters in adult populations, were identified, using PUBMED/Medline and Cochrane databases. The search focused as well on observational studies related to the effect of food processes on RS content. While processes such as milling, fermentation, cooking and heating seem to have a deleterious influence on RS content, other processes, such as cooling, cooking time, storage time, or water content, may positively impact its presence. Regarding the influence on health parameters, there is a body of evidence suggesting an overall significant beneficial effect of RS, especially type 1 and 2, on several health parameters such as glycemic response, insulin resistance index, bowel function or inflammatory markers. Effects are more substantiated in individuals suffering from metabolic diseases. The effects of RS may however be exerted differently depending on the type. A better understanding of the influence of food processes on RS can guide the development of dietary intake recommendations and contribute to the development of food products rich in RS.

Association of Dietary Resistant Starch Intake with Obesity and Metabolic Syndrome in Korean Adults

Research findings on the relationship between dietary resistant starch (RS) intake and metabolic diseases using population-based data are very scarce. This study examined the association of dietary RS intake with obesity and metabolic syndrome in Korean adults. A total of 12,491 adults (5292 men and 7199 women) were selected from the 2016-2018 Korea National Health and Nutrition Examination Survey data. The individual RS intake (g) was calculated by linking the 1-day 24 h recall data with the RS content database for common Korean foods. Obesity was defined as a BMI ≥ 25.0 kg/m2. Metabolic syndrome was defined as having three or more of the following: abdominal obesity, elevated triglycerides, low HDL cholesterol, elevated fasting blood glucose, and elevated blood pressure. Odds ratios (ORs) with 95% confidence intervals (CIs) for obesity and metabolic syndrome across quartiles (Qs) of RS intake were calculated using multiple logistic regression analysis. In men, the highest quartile of RS intake showed a significantly lower OR for metabolic syndrome compared to the lowest quartile after adjusting for covariates (OR = 0.71, 95% CI = 0.56-0.92, p-trend = 0.0057). Dietary RS intake in men was also inversely associated with obesity (Q4 vs. Q1: OR = 0.80, 95% CI = 0.67-0.97, p-trend = 0.0329) and elevated triglycerides (Q4 vs. Q1: OR = 0.80, 95% CI = 0.66-0.98, p-trend = 0.0314). In women, RS intake was not associated with metabolic syndrome. Our findings may serve as useful data for developing guidelines for RS intake and conducting further cohort and clinical studies to investigate the health effects of RS.

Characterization of green banana starch from "Songkibab" species cultivated in the southern part of Korea

Resistant starch (RS) has advantages for regulating the colon health as prebiotics and dietary fibers, and green banana has interested due to containing high amounts of RS. Here, the structural, physicochemical, and digestible characteristics of green banana starch from newly bred Songkibab (SB) were determined to evaluate its suitability for application as a new crop in response to global warming and for obtaining genetic diversity. SB starch has structural similarities to the Cavendish (CD) banana, which is widely consumed in Southeast Asia, in its ratio of B3-chains (in high amounts), flattened shapes of smooth surfaces, and B-type crystallinity. Physiochemically, SB shows comparable swelling power, amylose content, and viscosity pattern but a higher RS content. Conclusively, this study suggests that SB banana may be a good resource for replacing CD species with novel varieties in East Asia because of the high degree of similarity in the various characteristics.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-023-01331-z.

Gut microbial features and dietary fiber intake predict gut microbiota response to resistant starch supplementation

Resistant starch (RS) consumption can have beneficial effects on metabolic health, but the response, in terms of effects on the gut microbiota and host physiology, varies between individuals. Factors predicting the response to RS are not yet established and would be useful for developing precision nutrition approaches that maximize the benefits of dietary fiber intake. We sought to identify predictors of gut microbiota response to RS supplementation. We enrolled 76 healthy adults into a 7-week crossover study with 59 individuals completing the study. Participants consumed RS type 2 (RS2), RS type 4 (RS4), and digestible starch, for 10 d each with 5-d washout periods in between. We collected fecal and saliva samples and food records during each treatment period. We performed 16S rRNA gene sequencing and measured fecal short-chain fatty acids (SCFAs), salivary amylase (AMY1) gene copy number, and salivary amylase activity (SAA). Dietary fiber intake was predictive of the relative abundance of several amplicon sequence variants (ASVs) at the end of both RS treatments. AMY1-related metrics were not predictive of response to RS. SAA was only predictive of the relative abundance of one ASV after digestible starch supplementation. Interestingly, SCFA concentrations increased the most during digestible starch supplementation. Treatment order (the order of consumption of RS2 and RS4), alpha diversity, and a subset of ASVs were predictive of SCFA changes after RS supplementation. Based on our findings, dietary fiber intake and gut microbiome composition would be informative if assessed prior to recommending RS supplementation because these data can be used to predict changes in specific ASVs and fecal SCFA concentrations. These findings lay a foundation to support the premise that using a precision nutrition approach to optimize the benefits of dietary fibers such as RS could be an effective strategy to compensate for the low consumption of dietary fiber nationwide.

Assessing the Postprandial Glycemic Response to Japonica Rice (Oryza sativa L. cv. Koshihikari) with a Small Amount of Lysolecithin and Canola Oil in Japanese Adult Men: a Double-blind, Placebo-controlled, Crossover Study

A double-blind, placebo-controlled, crossover trial was performed to analyze the effects of a small amount of lysolecithin and canola oil on blood glucose levels after consuming japonica rice. Overall, 17 Japanese adult men were assigned to consume 150 g of normally cooked japonica rice (placebo group) and 150 g of japonica rice cooked with 18 mg of lysolecithin and 1.8 g of canola oil (treatment group); these lipids were added as emulsified formulation (EMF) for stability and uniformity. Subsequently, blood samples were collected before and 30, 45, 60, 90, and 120 min after consuming test foods. There was no significant difference in blood glucose, insulin, and triglyceride levels between the groups. However, a stratified analysis of 11 subjects with body mass index (BMI) ≥ 22 revealed that blood glucose levels were significantly lower after 30 min in the treatment group than in the placebo group (p = 0.041). Through in vitro digestibility test, the rice sample of the treatment group was observed to release significantly less glucose within 20 min than that in the placebo group rice. These results suggest that the combination of a small amount of lysolecithin and canola oil modulated the increase in postprandial blood glucose levels induced by the intake of cooked japonica rice in adult men with BMI ≥ 22. This clinical trial was registered with the University Hospital Medical Information Network (UMIN) Center, (UMIN000045744; registered on 15/10/2021).

Loss of function of SSIIIa and SSIIIb coordinately confers high RS content in cooked rice

The sedentary lifestyle and refined food consumption significantly lead to obesity, type 2 diabetes, and related complications, which have become one of the major threats to global health. This incidence could be potentially reduced by daily foods rich in resistant starch (RS). However, it remains a challenge to breed high-RS rice varieties. Here, we reported a high-RS mutant rs4 with an RS content of ~10.8% in cooked rice. The genetic study revealed that the loss-of-function SSIIIb and SSIIIa together with a strong Wx allele in the background collaboratively contributed to the high-RS phenotype of the rs4 mutant. The increased RS contents in ssIIIa and ssIIIa ssIIIb mutants were associated with the increased amylose and lipid contents. SSIIIb and SSIIIa proteins were functionally redundant, whereas SSIIIb mainly functioned in leaves and SSIIIa largely in endosperm owing to their divergent tissue-specific expression patterns. Furthermore, we found that SSIII experienced duplication in different cereals, of which one SSIII paralog was mainly expressed in leaves and another in the endosperm. SSII but not SSIV showed a similar evolutionary pattern to SSIII. The copies of endosperm-expressed SSIII and SSII were associated with high total starch contents and low RS levels in the seeds of tested cereals, compared with low starch contents and high RS levels in tested dicots. These results provided critical genetic resources for breeding high-RS rice cultivars, and the evolutionary features of these genes may facilitate to generate high-RS varieties in different cereals.

Resistant starch improves cardiometabolic disease outcomes: A narrative review of randomized trials

Healthy dietary patterns with adequate fiber improve cardiometabolic (CM) outcomes and attenuate disease progression. Resistant starch (RS) is a fermentable fiber that affects CM outcomes; however, studies are heterogeneous and inconsistent. Thus, the purpose of this narrative review is to assess the impact of RS intake by type and amount on CM outcomes while considering subject characteristics and trial duration. Randomized crossover or parallel studies (n = 31) were selected and compared according to acute (1 day; n = 12), medium (>1-30 days; n = 8), or long (>30 days; n = 11) duration. Most acute trials in healthy adults showed improvements in postprandial glycemic outcomes irrespective of RS type or amount. However, a more pronounced reduction occurred when test meals did not match for available carbohydrate. Daily RS intake had a minimal effect on CM outcomes in medium duration trials, but insulin resistant adults had better glycemic control at 4 weeks. Several longer duration trials (8-12 weeks) showed favorable CM outcomes with daily RS intake in adults with type 2 diabetes (T2D), but not in those at risk for T2D. Furthermore, some studies reported improved lipids, inflammatory biomarkers, and heart rate. Future studies should consider matching for available carbohydrates between the RS and control groups to understand the gut microbiome's role. Furthermore, energy and fiber should be considered. Overall, the acute intake of RS improves glycemic outcomes, and consuming RS at for least 4 and up to 8 to 12 weeks in adults with prediabetes and T2D, respectively, appears to improve CM outcomes.

Consumption of Solnul™ Resistant Potato Starch Produces a Prebiotic Effect in a Randomized, Placebo-Controlled Clinical Trial

The effects of resistant starch at high doses have been well-characterized, but the potential prebiotic effects of resistant starch at doses comparable to oligosaccharide prebiotics have not been evaluated. A three-arm randomized, double-blind, placebo-controlled clinical trial was conducted to evaluate the effect of 3.5 g and 7 g daily doses of Solnul^™ resistant potato starch (RPS) on beneficial populations of gut bacteria and stool consistency after a 4-week period. The relative abundance of Bifidobacterium and Akkermansia was determined by employing 16Sv4 sequencing of stool samples. To assess the effect of RPS on laxation and bowel movements, stools were recorded and scored using the Bristol Stool Form Scale. Participants consuming 3.5 g/day of RPS experienced significantly greater changes in Bifidobacterium and Akkermansia compared to the placebo after 4 weeks. The number of diarrhea- and constipation-associated bowel movements were both significantly lower in the 3.5 g RPS arm compared to the placebo group. Participants consuming 7 g of RPS responded similarly to those in the 3.5 g arm. Our analyses demonstrate that Solnul^™ RPS has a prebiotic effect when consumed for 4 weeks at the 3.5 g per day dose, stimulating increases in beneficial health-associated bacteria and reducing diarrhea- and constipation-associated bowel movements when compared to the placebo group.

Effect of resistant starch types as a prebiotic

Since the role of intestinal microbiota in metabolism was understood, the importance of dietary components such as fibres and prebiotics, which affect the modulation of microbiota, has been increasing day by day. While all prebiotic components are considered dietary fibre, not every dietary fibre is considered a prebiotic. While fructooligosaccharides, galactooligosaccharides, inulin, and galactans are considered prebiotics, other fermentable carbohydrates are considered candidate prebiotic components based on in vitro and preclinical studies. Resistant starch, one of such carbohydrates, is considered a potential prebiotic component when it is made resistant to digestion naturally or chemically. In this review, both in vitro and in vivo studies in which the prebiotic capacity of type II, type III, and type IV resistant starch isolated from food and produced commercially was assessed were analyzed. According to the results of current studies, certain types of resistant starch are thought to have a high prebiotic capacity, and they may be candidate prebiotic components although positive results have not been achieved in all studies. KEY POINTS: • Resistant starch is undigested in the small intestine and is fermented in the large intestine. • Resistant starch fermentation positively affects the growth of Bifidobacterium and Lactobacillus. • Resistant starch can be considered a prebiotic ingredient.

The association of dietary resistance starch intake with all-cause and cause-specific mortality

Background

Several studies have estimated daily intake of resistant starch (RS), but no studies have investigated the relationship of RS intake with mortality.

Objective

We aimed to examine associations between RS intake and all-cause and cause-specific mortality.

Methods

Data from US National Health and Nutrition Examination Survey (NHANES) from 1999 to 2018 with 24-h dietary recall data was used in current study. The main exposure in this study was RS intake, and the main outcome was the mortality status of participants until December 31, 2019. The multivariable Cox proportional hazards regression models were developed to evaluate the hazard ratios (HRs) and 95% confidence interval (95% CI) of cardiovascular disease (CVD), cancer, and all-cause mortality associated with RS intake.

Results

A total of 42,586 US adults [mean (SD) age, 46.91 (16.88) years; 22,328 (52.43%) female] were included in the present analysis. During the 454,252 person-years of follow-up, 7,043 all-cause deaths occurred, including 1,809 deaths from CVD and 1,574 deaths from cancer. The multivariable-adjusted HRs for CVD, cancer, and all-cause mortality per quintile increase in RS intake were 1 (95%CI, 0.97-1.04), 0.96 (95%CI, 0.93-1), and 0.96 (95%CI, 0.95-0.98), respectively. The associations remained similar in the subgroup and sensitivity analyses.

Conclusion

Higher RS intake is significantly associated with lower cancer and all-cause mortality, but not significantly with CVD mortality. Future studies focusing on other populations with different food sources of RS and RS subtypes are needed to access the dose-response relationship and to improve global dietary recommendations.

Culinary strategies to manage glycemic response in people with type 2 diabetes: A narrative review

Diet plays a critical role in the management of many chronic diseases. It is well known that individuals with type 2 diabetes (T2D) need to pay close attention to foods rich in carbohydrates to better manage their blood sugar. Usually, individuals are told to increase their dietary fiber intake which is associated with better glycemic control and limit their overall carbohydrate consumption. However, there are many other cooking strategies available to reduce the glycemic response to meals rich in carbohydrates and with a high glycemic index, such as adding fats, proteins, or vinegar, modifying the cooking or preparation processes, and even the selection and storage of foods consumed. The aim of the present narrative review is to summarize some of these existing strategies applied to the cooking process and their ability to modulate glycemic response to meals in individuals with T2D.

The gastrointestinal and microbiome impact of a resistant starch blend from potato, banana, and apple fibers: A randomized clinical trial using smart caps

The gastrointestinal (GI) impact of fibers including resistant starch (RS) consumption depends on various types and amounts of fibers, the initial microbiome states, and accurate intake measurements. A randomized clinical trial evaluated the GI impact of varying doses of a novel resistant starch blend (RSB) with smart cap monitoring. RSB contained at least 50% RS and was a proprietary mixture of a potato starch, green banana flour, and apple fiber powder (a source of apple pectin, not resistant starch). The study design randomized participants to one of four arms: 10 g/day of potato starch (0 RSB), 10 g/day of RSB, 10 to 20 to 20 g/day of RSB or 10 to 20 to 30 g/day RSB for two-week intervals over 6 weeks. Results confirmed that while resistant starch of approximately 5 g per day improves GI symptoms at 2, 4, and 6 weeks, it did not demonstrate a detectable effect on short chain fatty acids. Increasing doses of the blend (RSB) led to a decrease in the diarrhea score. Using an estimate of total consumption of RSB based on smart cap recordings of container openings and protocol-specified doses of RSB, a reduction in the sleep disturbance score was associated with higher RSB dose. The exploratory microbiome evaluation demonstrated that among the 16S rRNA gene sequences most associated with the consumption of the novel blend RSB, two belong to taxa of notable interest to human health: Faecalibacterium and Akkermansia.

Infancy Dietary Patterns, Development, and Health: An Extensive Narrative Review

Correct dietary patterns are important for a child’s health from birth to adulthood. Understanding a child’s health as a state of entire physical, mental, and social well-being is essential. However, reaching adulthood in a complete health proper state is determined by feeding and dietary habits during preconception, pregnancy, or children infancy. Different factors, such as the mother’s lifestyle, culture, or socioeconomic status, are crucial during all these phases. In this review, we aimed to assess the long-term associations between infancy dietary patterns and health and their influence on development and growth. To reach this objective, a consensus critical review was carried out using primary sources such as scientific articles, and secondary bibliographic indexes, databases, and web pages. PubMed, SciELO, and Google Scholar were the tools used to complete this research. We found that high-income countries promote high-calorie foods and, consequently, obesity problems among children are rising. However, undernutrition is a global health issue concerning children in low- and middle-income countries; thus, parental socioeconomic status in early life is essential to children’s health and development, showing that biological, social, and environmental influences are increased risk factors for chronic diseases. This narrative review is aimed to collect evidence for early nutritional intervention and future disease prevention.

Ketogenic and Modified Mediterranean Diet as a Tool to Counteract Neuroinflammation in Multiple Sclerosis: Nutritional Suggestions

Ketogenic Diet is a nutritional pattern often used as dietotherapy in inflammatory diseases, including neurological disorders. Applied on epileptic children since 1920, in recent years it has been taken into account again as a tool to both reduce inflammatory burdens and ameliorate the nutritional status of patients affected by different pathologies. Multiple sclerosis (MS) is considered an immune-mediated neuro-inflammatory disease and diet is a possible factor in its pathogenesis. The aim of this work is to investigate the main potential targets of MS-related impairments, in particular the cognitive deficits, focusing on the alteration of biomarkers such as the Brain Derived-Neurotrophic Factor and the Tryptophan/Kynurenine ratio that could play a role on neuroprotection and thus on MS progression. Furthermore, we here propose nutritional suggestions which are useful in the development of a ketogenic diet protocol that takes advantage of the anti-inflammatory properties of low-carbohydrate foods from the Mediterranean diet to be applied to subjects with MS. In conclusion, this approach will allow one to develop the ketogenic diet combined with a modified Mediterranean diet as a possible tool to improve neuroinflammation in multiple sclerosis.

Daily Inclusion of Resistant Starch-Containing Potatoes in a Dietary Guidelines for Americans Dietary Pattern Does Not Adversely Affect Cardiometabolic Risk or Intestinal Permeability in Adults with Metabolic Syndrome: A Randomized Controlled Trial

Poor diet quality influences cardiometabolic risk. Although potatoes are suggested to adversely affect cardiometabolic health, controlled trials that can establish causality are limited. Consistent with potatoes being rich in micronutrients and resistant starch, we hypothesized that their inclusion in a Dietary Guidelines for Americans (DGA)-based dietary pattern would improve cardiometabolic and gut health in metabolic syndrome (MetS) persons. In a randomized cross-over trial, MetS persons (n = 27; 32.5 ± 1.3 year) consumed a DGA-based diet for 2 weeks containing potatoes (DGA + POTATO; 17.5 g/day resistant starch) or bagels (DGA + BAGEL; 0 g/day resistant starch) prior to completing oral glucose and gut permeability tests. Blood pressure, fasting glucose and insulin, and insulin resistance decreased (p < 0.05) from baseline regardless of treatment without any change in body mass. Oral glucose-induced changes in brachial artery flow-mediated dilation, nitric oxide homeostasis, and lipid peroxidation did not differ between treatment arms. Serum endotoxin AUC0−120 min and urinary lactulose/mannitol, but not urinary sucralose/erythritol, were lower in DGA + POTATO. Fecal microbiome showed limited between-treatment differences, but the proportion of acetate was higher in DGA + POTATO. Thus, short-term consumption of a DGA-based diet decreases cardiometabolic risk, and the incorporation of resistant starch-containing potatoes into a healthy diet reduces small intestinal permeability and postprandial endotoxemia.

The Role of Dietary Fiber and Gut Microbiome Modulation in Progression of Chronic Kidney Disease

Nutrition is one of the fundamental approaches to promoting and preventing all kinds of diseases, especially kidney diseases. Dietary fiber forms a significant aspect of renal nutrition in treating chronic kidney disease (CKD). Dietary fiber intake influences the composition and metabolism of the gut microbiome with proven roles in reducing uremic toxin production, preserving kidney function, and retarding the progression of CKD through mechanisms of regulating metabolic, immunological, and inflammatory processes. Understanding dietary fiber’s pathogenesis and mechanistic action in modulating host and microbiome interactions provides a potential adjunct therapeutic target for preventing, controlling, and treating CKD patients. In this regard, a recommendation of adequate and appropriate dietary fiber intake to restore beneficial gut microbiota composition would reduce the risks and complications associated with CKD. This mini review summarizes current evidence of the role of dietary fiber intake in modulating the gut microbiome to improve kidney health.

Additional Resistant Starch from One Potato Side Dish per Day Alters the Gut Microbiota but Not Fecal Short-Chain Fatty Acid Concentrations

The composition of the gut microbiota and their metabolites are associated with cardiometabolic health and disease risk. Intake of dietary fibers, including resistant starch (RS), has been shown to favorably affect the health of the gut microbiome. The aim of this research was to measure changes in the gut microbiota and fecal short-chain fatty acids as part of a randomized, crossover supplemental feeding study. Fifty participants (68% female, aged 40 ± 13 years, BMI 24.5 ± 3.6 kg/m²) completed this study. Potato dishes (POT) contained more RS than refined grain dishes (REF) (POT: 1.31% wet basis (95% CI: 0.94, 1.71); REF: 0.73% wet basis (95% CI: 0.34, 1.14); p = 0.03). Overall, potato dish consumption decreased alpha diversity, but beta diversity was not impacted. Potato dish consumption was found to increase the abundance of Hungatella xylanolytica, as well as that of the butyrate producing Roseburia faecis, though fecal butyrate levels were unchanged. Intake of one potato-based side dish per day resulted in modest changes in gut microbiota composition and diversity, compared to isocaloric intake of refined grains in healthy adults. Studies examining foods naturally higher in RS are needed to understand microbiota changes in response to dietary intake of RS and associated health effects.

Does a high dietary intake of resistant starch affect glycaemic control and alter the gut microbiome in women with gestational diabetes? A randomised control trial protocol

BACKGROUND

Gestational Diabetes Mellitus (GDM) is prevalent with lasting health implications for the mother and offspring. Medical nutrition therapy is the foundation of GDM management yet achieving optimal glycaemic control often requires treatment with medications, like insulin. New dietary strategies to improve GDM management and outcomes are required. Gut dysbiosis is a feature of GDM pregnancies, therefore, dietary manipulation of the gut microbiota may offer a new avenue for management. Resistant starch is a fermentable dietary fibre known to alter the gut microbiota and enhance production of short-chain fatty acids. Evidence suggests that short-chain fatty acids improve glycaemia via multiple mechanisms, however, this has not been evaluated in GDM.

METHODS

An open-label, parallel-group design study will investigate whether a high dietary resistant starch intake or resistant starch supplement improves glycaemic control and changes the gut microbiome compared with standard dietary advice in women with newly diagnosed GDM. Ninety women will be randomised to one of three groups - standard dietary treatment for GDM (Control), a high resistant starch diet or a high resistant starch diet plus a 16 g resistant starch supplement. Measurements taken at Baseline (24 to 30-weeks' gestation), Day 10 and Day 56 (approximately 36 weeks' gestation) will include fasting plasma glucose levels, microbial composition and short-chain fatty acid concentrations in stool, 3-day dietary intake records and bowel symptoms questionnaires. One-week post-natal data collection will include microbial composition and short-chain fatty acid concentrations of maternal and neonatal stools, microbial composition of breastmilk, birthweight, maternal and neonatal outcomes. Mixed model analysis of variance will assess change in glycaemia and permutation-based multivariate analysis of variance will assess changes in microbial composition within and between intervention groups. Distance-based linear modelling will identify correlation between change in stool microbiota, short-chain fatty acids and measures of glycaemia.

DISCUSSION

To improve outcomes for GDM dyads, evaluation of a high dietary intake of resistant starch to improve glycaemia through the gut microbiome needs to be established. This will expand the dietary interventions available to manage GDM without medication.

TRIAL REGISTRATION

Australian New Zealand Clinical Trial Registry, ACTRN12620000968976p . Registered 28 September 2020.

Neither low salivary amylase activity, cooling cooked white rice, nor single nucleotide polymorphisms in starch-digesting enzymes reduce glycemic index or starch digestibility: a randomized, crossover trial in healthy adults

BACKGROUND

It was suggested that low salivary-amylase activity (SAA) and cooling or stir-frying cooked starch decreases its digestibility and glycemic index.

OBJECTIVE

We determined the effects of SAA, cooling, and single-nucleotide polymorphisms (SNPs) in the salivary amylase (AMY1), pancreatic amylase (AMY2A, AMY2B), maltase-glucoamylase (MGAM), and sucrase-isomaltase (SI) genes on starch digestibility and glycemic index of cooked polished rice.

METHODS

Healthy subjects [pilot, n = 12; main, n = 20 with low-SAA (<50 U/mL), and n = 20 with high-SAA (>105 U/mL)] consumed test meals containing 25 g (pilot) or 50 g (main) available carbohydrate at a contract research organization using open-label (pilot) or assessor-blinded (main), randomized, crossover, Latin-square designs (trial registration: NCT03667963). Pilot-trial test meals were dextrose, freshly cooked polished rice, cooked rice cooled overnight, stir-fried hot rice, or stir-fried cold rice. Main-trial test meals were dextrose, dextrose plus 10 g lactulose, plain hot rice, or plain cold rice. In both trials, blood glucose was measured fasting and at intervals over 2 h. In the main trial, breath hydrogen was measured fasting and hourly for 6 h to estimate in vivo starch digestibility. Data were analyzed by repeated-measures ANOVA for the main effects of temperature and stir-frying (pilot trial) or the main effects of SAA and temperature (main trial) and their interactions. Effects of 24 single nucleotide polymorphisms (SNPs) were assessed separately. Means were considered to be equivalent if the 95% CI of the differences were within ±20% of the comparator mean for glucose response/glycemic index or ±7% for digestibility.

RESULTS

Pilot: neither temperature nor stir-frying significantly affected glucose incremental AUC (primary endpoint, n = 12). Main: mean ± SEM glycemic index (primary endpoint, n = 40) was equivalent for low-SAA compared with high-SAA (73 ± 3 vs. 75 ± 4) and cold rice compared with hot rice (75 ± 3 vs. 70 ± 3). Estimated starch digestibility (n = 39) was equivalent for low-SAA compared with high-SAA (95% ± 1% vs. 92% ± 1%) and hot rice compared with cold rice (94% ± 1% vs. 93% ± 1%). No meaningful associations were observed between genotypes and starch digestibility or glycemic index for any of the SNPs.

CONCLUSIONS

The results do not support the hypotheses that low-SAA, cooling, and common genetic variations in starch-digesting enzymes affect the glycemic index or in vivo carbohydrate digestibility of cooked polished rice. This trial was registered at clinicaltrials.gov as NCT03667963.

Resistant Starches and Non-Communicable Disease: A Focus on Mediterranean Diet

Resistant starch (RS) is the starch fraction that eludes digestion in the small intestine. RS is classified into five subtypes (RS1-RS5), some of which occur naturally in plant-derived foods, whereas the others may be produced by several processing conditions. The different RS subtypes are widely found in processed foods, but their physiological effects depend on their structural characteristics. In the present study, foods, nutrition and biochemistry are summarized in order to assess the type and content of RS in foods belonging to the Mediterranean Diet (MeD). Then, the benefits of RS consumption on health are discussed, focusing on their capability to enhance glycemic control. RS enters the large bowel intestine, where it is fermented by the microbiome leading to the synthesis of short-chain fatty acids as major end products, which in turn have systemic health effects besides the in situ one. It is hoped that this review will help to understand the pros of RS consumption as an ingredient of MeD food. Consequently, new future research directions could be explored for developing advanced dietary strategies to prevent non-communicable diseases, including colon cancer.

Elucidation of the low resistant starch phenotype in Phaseolus vulgaris exhibited in the yellow bean Cebo Cela

Dry beans(Phaseolus vulgaris) are rich in complex carbohydrates including resistant starch (RS). RS, the starch fraction that escapes digestion, typically ranges from 35% in raw beans to 4% in cooked beans. A low RS bean genotype, Cebo Cela, was identified with 96% less RS (1.5% RS) than normal raw beans. The goal of this research was to elucidate the factors responsible for this low RS phenotype. The low RS phenotype was evaluated in whole bean flour and starch in Cebo Cela (yellow), Canario (yellow), Alpena (navy) and Samurai (otebo). α-Amylase activation was found to be a major contributor of the low RS content phenotype of the whole bean flour for Cebo Cela (-21.9% inhibition). Total starch (43.6%-40.2%), amylose (31.0%-31.5%), molecular weight and chain length distributions of amylose and amylopectin did not contribute to the low RS phenotype. Yellow bean starches were digested nearly 1.5 times (95%-94%) faster than starch granules from otebo and navy beans (65%-73%) due to lower proportions of amylopectin chains. PRACTICAL APPLICATION: This study is of value to the food industry because the yellow bean, Cebo Cela, is easily hydrolyzed by α-amylase and also has α-amylase promotion properties. Therefore, Cebo Cela can be used as an alternate starch source for ethanol fermentation and for the production of maltodextrins and fructose/glucose syrups which are used as food thickeners and sweeteners.

Ketogenic Diets and Chronic Disease: Weighing the Benefits Against the Risks

Very-low-carbohydrate ketogenic diets have been long been used to reduce seizure frequency and more recently have been promoted for a variety of health conditions, including obesity, diabetes, and liver disease. Ketogenic diets may provide short-term improvement and aid in symptom management for some chronic diseases. Such diets affect diet quality, typically increasing intake of foods linked to chronic disease risk and decreasing intake of foods found to be protective in epidemiological studies. This review examines the effects of ketogenic diets on common chronic diseases, as well as their impact on diet quality and possible risks associated with their use. Given often-temporary improvements, unfavorable effects on dietary intake, and inadequate data demonstrating long-term safety, for most individuals, the risks of ketogenic diets may outweigh the benefits.

Dietary fiber, starch, and sugars in bananas at different stages of ripeness in the retail market

The goal of this work was to evaluate changes in dietary fiber measured by the traditional enzymatic-gravimetric method (AOAC 991.43) and the more recently accepted modified enzymatic-gravimetric method (AOAC 2011.25), mono- and disaccharides, and starch as a function of assessed ripeness in a controlled study of a single lot of bananas and in bananas at the same assessed stages of ripeness from bananas purchased in retail stores, from different suppliers. Sugars, starch, and dietary fiber were analyzed in bananas from a single lot, at different stages of ripeness, and in retail samples at the same assessed stages of ripeness. Mean fiber measured by the traditional enzymatic-gravimetric method (EG) was ~2 g/100g and not affected by ripeness. Mean fiber assessed with the recently modified method (mEG) was ~18 g/100g in unripe fruit and decreased to 4-5 g/100g in ripe and ~2 g/100g in overripe bananas. Slightly ripe and ripe bananas differed by ~1.1 g/100g in the controlled single-lot study but not among retail samples. There was a large increase in fructose, glucose and total sugar going from unripe to ripe with no differences between ripe and overripe. Aside from stage of ripeness, the carbohydrate composition in retail bananas is likely affected by differences in cultivar and post-harvest handling. Results from this study demonstrate the importance of measuring dietary fiber using the mEG approach, developing more comprehensive and sensitive carbohydrate analytical protocols and food composition data, and recognizing the impact of different stages of maturity and ripeness on carbohydrate intake estimated from food composition data.

Pasta from yellow lentils: How process affects starch features and pasta quality

The effects of conventional extrusion (CV) and extrusion-cooking (EC) were investigated on 100% yellow lentils (YL). Both the extrusion processes led to pasta with good cooking quality (cooking loss: 7.0-7.1 g/100 g, firmness: 530-608 N), even in overcooking (cooking loss: 7.7-7.9 g/100 g, firmness: 418-513 N). Contrary to what is known for gluten-free cereals, CV is effective in producing pasta from native YL with no need for a pre-gelatinization step. However, pasta from EC showed a higher compression energy (2898 versus 2448 N*mm). In this sample, starch presented a higher degree of gelatinization (75.5 versus 57.6 g/100 g) and lower enthalpy (0.97 versus 1.07 J/g). At the same time, EC promoted a more compact structure that required higher temperature for melting (66.49 versus 63.16 °C) and showing pasting properties (79.1 versus 74.7 °C). Thus, by selecting suitable extrusion conditions it is possible to improve the cooking behavior of 100% pulse pasta.

Association between Fruit and Vegetable Intakes and Mental Health in the Australian Diabetes Obesity and Lifestyle Cohort

Increasing prevalence of mental health disorders within the Australian population is a serious public health issue. Adequate intake of fruits and vegetables (FV), dietary fibre (DF) and resistant starch (RS) is associated with better mental and physical health. Few longitudinal studies exist exploring the temporal relationship. Using a validated food frequency questionnaire, we examined baseline FV intakes of 5845 Australian adults from the AusDiab study and estimated food group-derived DF and RS using data from the literature. Perceived mental health was assessed at baseline and 5 year follow up using SF-36 mental component summary scores (MCS). We conducted baseline cross-sectional analysis and prospective analysis of baseline dietary intake with perceived mental health at 5 years. Higher baseline FV and FV-derived DF and RS intakes were associated with better 5 year MCS (p < 0.001). A higher FV intake (754 g/d vs. 251 g/d, Q4 vs. Q1) at baseline had 41% lower odds (OR = 0.59: 95% CI 0.46–0.75) of MCS below population average (<47) at 5 year follow up. Findings were similar for FV-derived DF and RS. An inverse association was observed with discretionary food-derived DF and RS. This demonstrates the association between higher intakes of FV and FV-derived DF and RS with better 5 year mental health outcomes. Further RCTs are necessary to understand mechanisms that underlie this association including elucidation of causal effects.

Pulse Probiotic Superfood as Iron Status Improvement Agent in Active Women-A Review

Active women or women of reproductive age (15–49 years old) have a high risk of suffering from anaemia. Anaemia is not solely caused by iron deficiency, however, the approaches to improve iron status in both cases are greatly related. Improving the iron status of active women can be done by dietary intervention with functional food. This review aims to provide insights about the functional food role to increase iron absorption in active women and the potency of pulse probiotic superfood development in dry matrices. Results showed that the beneficial effect of iron status is significantly improved by the synergic work between probiotic and prebiotic. Furthermore, chickpeas and lentils are good sources of prebiotic and the consumption of pulses are related with 21st century people’s intention to eat healthy food. There are wide possibilities to develop functional food products incorporated with probiotics to improve iron status in active woman.

Nutritional Bar with Potato-Based Resistant Starch Attenuated Post-Prandial Glucose and Insulin Response in Healthy Adults

Resistant starch is a non-digestible starch fraction and is classified as fiber. Beyond naturally occurring fiber sources, starches can be modified to resist digestion, increase their fiber content and provide physiological benefits. The current study examined acute postprandial glycemic responses of VERSAFIBE™ 1490 resistant starch type-4, containing 90% total dietary fiber (TDF, AOAC (Association of Official Analytical Collaboration International) 991.43 method). In a double-blind, randomized, placebo-controlled, cross-over study, healthy adults (n = 38) consumed a nutritional bar containing either control (2 g), medium (21 g) or high (30 g) fiber. The test bars were matched with control for available carbohydrates, fat and protein. Venous glucose, insulin, and capillary glucose were measured. Mean ± SEM capillary glucose incremental area-under-curve (iAUC0)-120 min in min*mmol/L was lower (p < 0.005) for both fiber bars (136.2 ± 9.2 and 137.0 ± 10.4 for the medium and high fiber bars, respectively) compared to the control bar (174.9 ± 13.5). Mean venous insulin iAUC0-120 min in min*pmol/L was also lower for medium (8096.3 ± 894.5) and high fiber (7533.8 ± 932.9) bars, respectively, compared to the control bar (11871.6 ± 1123.9, p < 0.001). Peak capillary glucose and venous insulin concentrations were also significantly reduced (p < 0.001) after consumption of both fiber bars compared to the control bar. The results of this study suggest that nutritional bars containing potato based RS4 fiber reduced post-consumption glycemic and insulinemic responses when consumed by generally healthy adults.

Total and resistant starch from foodstuff for animal and human consumption in Costa Rica

Starchy ingredients are a key source of carbohydrates and have an essential role in a healthy diet. Starch amount in foodstuffs is paramount as it allows diet professionals to base their formulations on scientific data. Herein, the total (TS) and resistant starch (RS) content, in a selection of typical starchy foods available on the Costa Rican market, for both human and animal consumption, is reported. The major types of starch, including physically encapsulated starch, were determined using in vitro methods AOAC OMASM methods 996.11, 2014.10, 996.11, 2002.02 and AACC 76-13.01 and 32-40.01. Samples were collected during 5 years as part of national surveillance plans. For feedstuffs, n = 252 feed ingredients (e.g., cornmeal and wheat products), n = 103 feeds (e.g., dairy and beef cattle), and n = 150 feed ingredient samples (selected based on their usage in feed formulations) were assessed for RS. In food commodities, sample numbers ascended to n = 287 and n = 371 for TS and RS, respectively (e.g. bananas). Feed ingredients with higher TS values were cassava meal, bakery by-products, rice/broken, sweet potato, and cornmeal (93.37, 81.67, 72.33, 66.66, and 61.43 g/100 g, respectively). TS for beef and dairy cattle, pig, and calf feeds, ranged from 30.26 to 34.46 g/100 g. Plantain/green banana flour, as a feed ingredient, exhibited RS absolute and relative contributions of 37.04 g/100 g and 53.89%, respectively. Products with a higher TS content included banana flour, green plantain flour, japonica rice, and cassava flour (62.87, 63.10, 72.90, 83.37 g/100 g). The primary RS sources in the Costa Rican diet are, in absolute terms, green plantain and malanga (50.41 and 56.59 g/100 g). Depending on a person's food habits, these sources may contribute in the range of 20-30 grams of RS per day. TS and RS intake may vary considerably among ingredients, and the contribution of RS may be of nutritional importance for specific individuals.

Usual Dietary Intake of Resistant Starch in US Adults from NHANES 2015-2016

BACKGROUND

Resistant starch (RS) confers many health benefits, mostly due to nonenzymatic human digestion and gut microbiota fermentation capacity. The usual intake of naturally occurring dietary RS in US adults is unclear.

OBJECTIVES

This study estimated usual daily RS intake in grams per 1000 kcal in US adults by sex, age, and ethnic group, as well as the most frequent food category contributing to RS intake using data from the NHANES 2015-2016.

METHODS

RS content of foods consumed was matched with Food and Nutrient Database for Dietary Studies food codes. The National Cancer Institute method was used to estimate adults' usual RS intake from 2 24-h dietary recalls. Day 1 RS contribution from food groups to overall RS intake was ranked for the total sample, across age-sex categories, and across ethnic groups.

RESULTS

In total, 5139 US adults (48.4% male) had a mean daily usual intake of RS of 1.9 ± 0.0 g/(1000 kcal⋅d). Males and females had a similar intake of RS [2.0 ± 0.0 g compared with 1.9 ± 0.0 g/(1000 kcal⋅d)] with no differences between sexes within the same age category. When comparing ethnic groups within each age category, the non-Hispanic white males and females had significantly lower RS intake than all other ethnic groups [range: 1.7-1.8 compared with 2.1-2.3 g RS/(1000 kcal⋅d), respectively], with no differences among the other ethnic groups. French fries and other fried white potatoes, rice, and beans, peas, and legumes were the most frequently consumed food categories contributing to RS intake in all adults.

CONCLUSIONS

US adults should improve the intake of natural RS food sources. Increasing RS intake will improve gastrointestinal health as a prebiotic and potentially increase insulin sensitivity with adequate consumption (e.g., ∼15 g/d).