Resistant starch ameliorated insulin resistant in patients of type 2 diabetes with obesity: a systematic review and meta-analysis.

BACKGROUND: Resistant starch (RS) is a starch that can be fermented by the microbial flora within gut lumen. Insulin resistance (IR) is a pathophysiological condition related to diabetes and obesity. RS could reduce blood glucose and ameliorate IR in animals, but its effect in human population is controversial. OBJECTIVE: The authors conducted a systematic literature review to evaluate the effect of RS diet supplement on ameliorating IR in patients with T2DM and simple obesity. METHODS: Databases that supplemented with RS in ameliorating IR in T2DM and simple obesity were queried for studies on or before August 15, 2018. Parameters including fasting insulin, fasting glucose, body mass index (BMI), homeostatic model assessment (HOMA) etc. were extracted from studies to systemically evaluate effects of RS. RESULTS: The database search yielded 14 parallel or crossover studies that met the inclusion criteria. The results indicated that there was no significant difference in the amelioration of BMI, HOMA-%S and HOMA-%B in T2DM patients between RS and the non-RS supplementation. However, the fasting blood glucose, fasting insulin and HOMA-IR in T2DM with obesity who supplemented RS were lower than control group, and the subgroup analysis according to the dose of RS supplementation was inconsistency. There was no significant difference between RS and non-RS supplements in patients with simple obesity. CONCLUSION: RS supplementation can ameliorate IR in T2DM, especially for the patients of T2DM with obesity, but not in simple obesity.

Carbohydrate Replacement of Rice or Potato with Lentils Reduces the Postprandial Glycemic Response in Healthy Adults in an Acute, Randomized, Crossover Trial.

Background: The postprandial blood glucose response (PBGR) following carbohydrate replacement of high-glycemic index (GI) foods with pulses, in a mixed meal, has not been accurately defined. Objective: We aimed to determine the extent to which PBGR and relative glycemic response (RGR) are lowered when half of the available carbohydrate (AC) from rice or potato is replaced with cooked lentils. Methods: Using a crossover design, 2 groups of 24 healthy adults randomly consumed 50 g AC from control white rice alone [mean ± SD body mass index (BMI, in kg/m2): 24.3 ± 0.5; mean ± SD age: 27.7 ± 1.2 y], instant potato alone (BMI: 24.0 ± 0.5; age: 27.4 ± 1.2 y), or the same starch source in a 50:50 AC combination with each of 3 types of commercially available lentils (large green, small green, split red). Fasting and postprandial blood samples were analyzed for glucose and insulin, and used to derive incremental area under the curve (iAUC), RGR, and maximum concentration (Cmax). Treatment effects were assessed with the use of repeated-measures ANOVA within the rice and potato treatments. Results: In comparison to rice alone, blood glucose iAUC and Cmax (P < 0.001) were lowered after consumption of rice with large green (P = 0.057), small green (P = 0.002), and split red (P = 0.006) lentils. Blood glucose iAUC and Cmax were also significantly lowered (P < 0.0001) after consumption of potato combined with each lentil, compared to potato alone. Plasma insulin iAUC and Cmax were significantly (P < 0.001) decreased when lentils were combined with potato, but not with rice. The RGRs of rice and potato were lowered by ∼20% and 35%, respectively, when half of their AC was replaced with lentils. Conclusions: Replacing half of the AC from high-GI foods with lentils significantly attenuates PBGR in healthy adults; this can contribute to defining a health claim for pulses and blood glucose lowering. This trial was registered at clinicaltrials.gov as NCT02426606.

Effects of pea with barley and less-processed maize on glycaemic control in diabetic dogs.

The source of starch may interfere with glycaemic control in dogs, but few studies have evaluated these aspects in diabetic dogs. This study compared the effects of two isonutrient diets with different starch sources, peas and barley (PB) v. maize (Mi), on diabetic dogs. The Mi diet was processed in order to generate a lower starch gelatinisation index. In all, fifteen adult diabetic dogs without other conditions were included. The animals were fed two dry extruded rations with moderate levels of fat and starch and high levels of protein and fibre using a random, double-blind cross-over design. Glycaemic curves over 48 h were developed via continuous glucose monitoring after 60 d on each diet and with the same neutral protamine Hagedorn (NPH) insulin dosage. The following were compared: fasting, mean, maximum and minimum blood glucose, maximum and minimum glycaemia difference, glycaemic increment, area under the glycaemic curve, area under the glycaemic increment curve and serum fructosamine concentration. Paired t tests or Wilcoxon signed-rank tests were used to compare the amount of food and nutrients ingested and the dietary effects on glycaemic variables between the diets. Dogs fed the PB diet presented a lower average mean interstitial glucose (P=0·01), longer mean hypoglycaemic time (P<0·01), shorter mean hyperglycaemic time (P<0·01) and smaller difference between maximum and minimum blood glucose levels (P=0·03). Thus, the processing applied to the Mi diet was not sufficient to achieve the same effects of PB on glycaemic control in diabetic dogs.

Polyphenol- and fibre-rich dried fruits with green tea attenuate starch-derived postprandial blood glucose and insulin: a randomised, controlled, single-blind, cross-over intervention.

Polyphenol- and fibre-rich foods (PFRF) have the potential to affect postprandial glycaemic responses by reducing glucose absorption, and thus decreasing the glycaemic response of foods when consumed together. A randomised, single-blind, cross-over study was conducted on sixteen healthy volunteers to test whether PFRF could attenuate postprandial blood glucose in healthy volunteers when added to a source of carbohydrate (starch in bread). This is the first study to examine the effects of a meal comprised of components to inhibit each stage of the biochemical pathway, leading up to the appearance of glucose in the blood. The volunteers were fasted and attended four visits: two control visits (bread, water, balancing sugars) and two test visits (single and double dose of PFRF) where they consumed bread, water and PFRF. Blood samples were collected at 0 (fasted), 15, 30, 45, 60, 90, 120, 150 and 180 min after consumption. The PFRF components were tested for α-amylase and α-glucosidase inhibitory potential in vitro. Plasma glucose was lower after consumption of both doses compared with controls: lower dose, change in mean incremental areas under the glucose curves (IAUC)=-27·4 (sd 7·5) %, P<0·001; higher dose, IAUC=-49·0 (sd 15·3) %, P<0·001; insulin IAUC was also attenuated by-46·9 (sd 13·4) %, P<0·01. Consistent with this, the polyphenol components of the PFRF inhibited α-amylase (green tea, strawberry, blackberry and blackcurrant) and α-glucosidase (green tea) activities in vitro. The PFRF have a pronounced and significant lowering effect on postprandial blood glucose and insulin response in humans, due in part to inhibition of α-amylase and α-glucosidase, as well as glucose transport.

Resistant starch and protein intake enhances fat oxidation and feelings of fullness in lean and overweight/obese women.

BACKGROUND: Diets high in either resistant starch or protein have been shown to aid in weight management. We examined the effects of meals high in non-resistant or resistant starch with and without elevated protein intake on substrate utilization, energy expenditure, and satiety in lean and overweight/obese women. METHODS: Women of varying levels of adiposity consumed one of four pancake test meals in a single-blind, randomized crossover design: 1) waxy maize (control) starch (WMS); 2) waxy maize starch and whey protein (WMS+WP); 3) resistant starch (RS); or 4) RS and whey protein (RS+WP). RESULTS: Total post-prandial energy expenditure did not differ following any of the four test meals (WMS = 197.9 ± 8.9; WMS+WP = 188 ± 8.1; RS = 191.9 ± 8.9; RS+WP = 195.8 ± 8.7, kcals/180 min), although the combination of RS+WP, but not either intervention alone, significantly increased (P <0.01) fat oxidation (WMS = 89.5 ± 5.4; WMS+WP = 84.5 ± 7.2; RS = 97.4 ± 5.4; RS+WP = 107.8 ± 5.4, kcals/180 min). Measures of fullness increased (125% vs. 45%) and hunger decreased (55% vs. 16%) following WP supplemented versus non-whey conditions (WMS+WP, RS+WP vs. WMS, RS), whereas circulating hunger and satiety factors were not different among any of the test meals. However, peptide YY (PYY) was significantly elevated at 180 min following RS+WP meal. CONCLUSIONS: The combined consumption of dietary resistant starch and protein increases fat oxidation, PYY, and enhances feelings of satiety and fullness to levels that may be clinically relevant if maintained under chronic conditions. This trial was registered at clinicaltrials.gov as NCT02418429.

Comparing effects of carbohydrate (CHO) blockers and trivalent chromium on CHO-induced insulin resistance and elevated blood pressure in rats.

OBJECTIVE: In Sprague-Dawley rats (SD), we compared two categories of natural dietary supplements that influence carbohydrate (CHO) metabolism via different basic mechanisms to ameliorate insulin resistance (IR) and elevated blood pressure (BP) associated with heavy sugar/starch consumption. Two dietary supplements (bean extract and l-arabinose) are often referred to as carb blockers (CBs), because they slow the gastrointestinal absorption of CHO. Trivalent chromium (CR) falls into a group of so-called insulin sensitizers, because its major effect is to enhance peripheral insulin sensitivity. METHOD: We divided 48 mature male SD into 4 groups of 12. The first group received powdered baseline diet alone (Con). The remaining 3 SD groups (groups 2-4) ingested regular rat chow containing 20% w/w sucrose and 20% w/w rice starch. The second group received only this CHO-enriched chow. To the high-CHO diets of the remaining two groups, either CB to slow CHO absorption (CHO + CB) (group 3) or an insulin sensitizer, trivalent CR (CHO + CR; group 4), was added. RESULTS: Compared to Con group 1, adding high CHO content to the diet of group 2 significantly increased circulating glucose levels and systolic BP (SBP). Addition of CB or CR to the feed of groups 3 and 4 overcame the perturbations that occurred with high CHO challenge in group 2; that is, they lowered circulating glucose concentrations to Con levels, enhanced response to exogenous insulin, and overcame the gradual elevation of SBP. Compared to group 2, the two treatment groups (3 and 4) also showed decreased renin-angiotensin system activity, decreased serum angiotensin-converting enzyme activity, and enhanced nitric oxide activity. CONCLUSIONS: Our data indicate that high doses of CB and CR, despite their different mechanisms of action, can completely overcome CHO-induced IR and BP elevations. The data further suggest that CB and CR affect only the changes brought on by heavy CHO ingestion, because IR and SBP in groups 3 and 4 mirrored Con values (group 1), never producing values lower than baseline. Earlier use of CB and CR in the life cycle appears more effective in overcoming CHO-induced perturbations than later use.

Reformulating cereal bars: high resistant starch reduces in vitro digestibility but not in vivo glucose or insulin response; whey protein reduces glucose but disproportionately increases insulin.

BACKGROUND: Resistant starch (RS) and whey protein are thought to be effective nutrients for reducing glycemic responses. OBJECTIVE: We aimed to determine the effect of varying the sucrose, RS, and whey protein content of cereal bars on glucose and insulin responses. DESIGN: Twelve healthy subjects [mean ± SD age: 36 ± 12 y; mean ± SD body mass index (in kg/m2): 24.9 ± 2.7] consumed 40 g available-carbohydrate (avCHO) portions of 5 whole-grain cereal bars that contained varying amounts of RS and whey protein concentrate [WPC; 70% protein; RS:WPC, %wt:wt: 15:0 (Bar15/0); 15:0, low in sucrose (Bar15/0LS); 15:5 (Bar15/5); 10:5 (Bar10/5); and 10:10 (Bar10/10)] and 2 portion sizes of a control bar low in whole grains, protein, and RS [control 1 contained 40 g avCHO (Control1); control 2 contained total carbohydrate equal to Bar15/0LS (Control2)] on separate days by using a randomized crossover design. Glucose and insulin responses in vivo and carbohydrate digestibility in vitro were measured over 3 h. RESULTS: Incremental area under the curve (iAUC) over 0-3 h for glucose (min × mmol/L) differed significantly between treatments (P < 0.001) [Bar15/0LS (mean ± SEM), 169 ± 14; Control2, 164 ± 20; Bar15/0, 144 ± 15; Control1, 140 ± 17; Bar10/5, 117 ± 12; Bar15/5, 116 ± 9; and Bar10/10, 100 ± 9; Tukey's least significant difference = 42, P < 0.05], but insulin iAUC did not differ significantly. Higher protein content was associated with a lower glucose iAUC (P = 0.028) and a higher insulin-to-glucose iAUC ratio (P = 0.002) All 5 RS-containing bars were digested in vitro ∼30% more slowly than the control bars (P < 0.05); however, in vivo responses were not related to digestibility in vitro. Glucose and insulin responses elicited by high-RS, whey protein-free bars were similar to those elicited from control bars. CONCLUSIONS: The inclusion of RS in cereal bar formulations did not reduce glycemic responses despite slower starch digestion in vitro. Thus, caution is required when extrapolating in vitro starch digestibility to in vivo glycemic response. The inclusion of whey protein in cereal bar formulations to reduce glycemic response requires caution because this may be associated with a disproportionate increase in insulin as judged by an increased insulin-to-glucose iAUC ratio. This trial was registered at clinicaltrials.gov as NCT02537587.

Preparation of a novel starch-derived three-dimensional ordered macroporous carbon for improving the dissolution rate and oral bioavailability of water-insoluble drugs.

In our study, soluble starch was applied as a novel carbon source for preparing three-dimensional ordered macroporous carbon (3DOMC) using monodisperse silica nanospheres as the hard template. The 3DOMC was used as an insoluble drug carrier when it was found that it could markedly improve the water solubility of felodipine (FDP). The structural features of 3DOMC were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The 3DOMC structure was found to have a higher drug loading than microporous and mesoporous structures, and the interconnected nanostructure effectively inhibited the formation of drug crystals. FDP, belonging to the Biopharmaceutics Classification System II (BCSII), was chosen as the model drug and was loaded into the 3DOMC structure by solvent evaporation. The state of FDP in the 3DOMC structure was characterized by powder X-ray diffractometry (PXRD), differential scanning calorimetry (DSC) and Fourier-transform infrared spectroscopy (FTIR). The results obtained showed that FDP was present in the pores in an amorphous or microcrystalline state. In vivo and in vitro experiments indicated that 3DOMC could significantly improve the drug dissolution rate, but the FDP-3DOMC self-made common tablets had the disadvantage of a burst effect. For this reason, osmotic pump technology was used to control the drug release rate. We developed a potentially useful insoluble drug carrier for pharmaceutical applications.

Impact of cyclodextrins on postprandial glycemia: evaluation in experimental animal model using the real-time continuous glucose monitoring system.

The impact of cyclodextrins (CDs) on postprandial glycemic response employing the real-time continuous glucose monitoring system (RT-CGMS) was investigated. For this purpose, α-CD, ß-CD, γ-CD, HP-ß-CD, curdlan, and dextrin at doses of 10 and 100 mg/kg were orally administered in rats. The RT-CGMS was efficient to evaluate the impact of CDs on postprandial glycemia. The results showed that α-CD, ß-CD, dextrin, and curdlan did not reduce the glycemic response after the administration of starch. In contrast, the HP-ß-CD (100 mg/kg) attenuated the rise in glycemia. Moreover, the γ-CD blunts the postprandial glycemic excursion at doses of 10 and 100 mg/kg. Therefore, γ-CD could attenuate the rise in glycemia promoted by oral administration of starch. Considering that the treatment of postprandial hyperglycemia is necessary to prevent type 2 diabetes, this study opens the perspective of better control of postprandial glycemia by the addition of γ-CD in food.

Changes in the molecular composition of circulating hydroxyethyl starch.

1. Hydroxyethyl starch (HES) of molecular weight 450,000 has been extensively investigated as a plasma volume expander and HES of molecular weight 60,000 has been proposed for use as a cryoprotective agent in the freezing for preservation of red blood cells. In these applications considerable amounts of HES may be injected intravenously and it is therefore desirable to understand its behaviour in vivo.2. After intravenous injection into rabbits, plasma levels of HES and clinical dextrans were determined using anthrone. HES persisted longer in the circulation than did the dextrans.3. HES was recovered from the bloodstream of rabbits and shown by gel filtration to be of a narrower molecular size distribution than the injected material. Smaller molecules were removed, presumably by filtration at the glomerulus. Larger molecules may have been removed by cells of the reticuloendothelial system or possibly through the action of amylase.4. The amylase in saliva was shown to break down HES into molecules of intermediate size with very little production of maltose units.

Passage of particles through the wall of the gastrointestinal tract.

In the normal process of digestion, not only substances in solution are absorbed. Solid, undissolved particles in macrocorpuscular form, are "kneaded" into the mucosa during their passage through the digestive tract. These particles in the micrometer size range pass between the epithelial cells into the subepithelial layer. From here they are transmitted both by the lymph vessels and by the mesenteric veins into the circulation, where they remain for a considerable time. This phenomenon, termed persorption, was investigated in detail.

Biodegradable microspheres. IV: Factors affecting the distribution and degradation of polyacryl starch microparticles.

Polyacryl starch microparticles have been suggested as lysosomotropic drug carriers. In this paper we report the study of the distribution and elimination of polyacryl starch microparticles after intravenous administration in mice. The half-life of the particles in the circulation is short (less than 5 min) and they are efficiently taken up by the reticuloendothelial (RES) system, mainly in the liver (50-90%). The stability of the particles, as studied both in vitro (with serum and lysosome preparations) and in vivo (via the elimination from the liver), depends on two factors, the amount of initiator of the polymerization process (N,N,N',N'-tetramethylethylenediamine, TEMED) and the degree of derivatization of the starch. TEMED, used for the polymerization of the acryl groups forming the hydrocarbon chains, determines the number and the length of the cross-links between the starch molecules. The results indicate that large amounts of TEMED induce the formation of particles with many and short cross-links, which are easily degraded and dissolved in serum and more rapidly eliminated from the liver. The stability in serum can be improved by coadministration of soluble starch. Prolonged treatment of the starch with acrylic acid glycidyl ester leads to a high degree of derivatization and, consequently, to less degradable particles remaining in the lysosomes of the RES. The extent of biodegradation of the polyacryl starch particles could be anticipated from in vitro degradation of the monomers (acryloylated starch) with amyloglucosidase.

Comparison of hypertonic saline/dextran versus hypertonic saline/hetastarch for resuscitation of hypovolemia.

In the present study, we compare resuscitation of bled sheep with hypertonic saline/dextran or hypertonic saline/hetastarch. Unanesthetized sheep were subjected to 2 h of hemorrhagic hypotension and then resuscitated with 200 ml of 7.5% NaCl solution made up to include either 6% dextran 70 (Macrodex) or 6% hetastarch (Hespan). Both solutions provided an immediate and sustained improvement in arterial pressure and cardiac output. The hypertonic saline/dextran provided a slightly better overall response as mean arterial pressure, cardiac output and central venous pressure were higher in the dextran group at all times post resuscitation. However, only the differences in arterial pressure and initial plasma volume expansion were statistically significant. The somewhat better response to hypertonic saline/dextran may be explained by the higher oncotic pressures generated by dextran compared to equal concentrations of hetastarch.

Persorption of raw starch: a cause of senile dementia?

Intact starch granules in food can pass through the intestinal wall and enter the circulation. They remain intact if they have not been cooked for long enough in the presence of water. Some of these granules embolise arterioles and capillaries. In most organs the collateral circulation suffices for continued function. In the brain, however, neurones may be lost. Over many decades the neuronal loss could be of clinical importance. To test this hypothesis, there is a need to examine brains for the presence of embolised starch granules. Examining tissues polariscopically clearly distinguishes starch granules from other objects of similar appearance.

Iron uptake and ferrokinetics in healthy male subjects of an iron-based oral phosphate binder (SBR759) labeled with the stable isotope (58)Fe.

SBR759 is a novel polynuclear iron(III) oxide-hydroxide starch·sucrose·carbonate complex being developed for oral use in chronic kidney disease (CKD) patients with hyperphosphatemia on hemodialysis. SBR759 binds inorganic phosphate released by food uptake and digestion in the gastro-intestinal tract increasing the fecal excretion of phosphate with concomitant reduction of serum phosphate concentrations. Considering the high content of ∼20% w/w covalently bound iron in SBR759 and expected chronic administration to patients, absorption of small amounts of iron released from the drug substance could result in potential iron overload and toxicity. In a mechanistic iron uptake study, 12 healthy male subjects (receiving comparable low phosphorus-containing meal typical for CKD patients: ≤1000 mg phosphate per day) were treated with 12 g (divided in 3 × 4 g) of stable (58)Fe isotope-labeled SBR759. The ferrokinetics of [(58)Fe]SBR759-related total iron was followed in blood (over 3 weeks) and in plasma (over 26 hours) by analyzing with high precision the isotope ratios of the natural iron isotopes (58)Fe, (57)Fe, (56)Fe and (54)Fe by multi-collector inductively coupled mass spectrometry (MC-ICP-MS). Three weeks following dosing, the subjects cumulatively absorbed on average 7.8 ± 3.2 mg (3.8-13.9 mg) iron corresponding to 0.30 ± 0.12% (0.15-0.54%) SBR759-related iron which amounts to approx. 5-fold the basal daily iron absorption of 1-2 mg in humans. SBR759 was well-tolerated and there was no serious adverse event and no clinically significant changes in the iron indices hemoglobin, hematocrit, ferritin concentration and transferrin saturation.

Determination of cyclodextrins and branched cyclodextrins by reversed-phase chromatography with pulsed amperometric detection and a membrane reactor.

A high-performance liquid chromatographic method has been developed for the determination of cyclodextrins (CDs) and branched CDs. The method involves their separation on a reversed-phase column using a mixture of water and acetonitrile as an eluant, eluant pH modification with a cation-exchange membrane reactor surrounded by 1.5 M sodium hydroxide solutions, and pulsed amperometric detection with a gold working electrode. The calibration graphs constructed by peak height versus injected amount were linear over the ranges 50-1000 pmol. The detection limits for CDs and branched CDs were about 1-5 pmol at a signal-to-noise ratio of 3. The method was successfully applied to the assay of beta-CD in serum samples.

[Safe use of microcrystalline cellulose in low-calorie foods]. / Zur Frage der Unbedenklichkeit bei der Verwendung von mikrokristalliner Cellulose für kalorienreduzierte Lebensmittel

The problems arising in using microcrystalline cellulose in the food industry are outlined. Like starch granules, microcrystalline cellulose is also persorbed by the human and animal organism. As long as the problem persists whether persorption is a normal, everyday process or a process which is detrimental in the long run, the statement that the use of greater amounts of microcrystalline cellulose for foods and pharmaceutical products is absolutely safe should be carefully examined.