Metabolism and bioavailability of newly developed dietary fiber materials, resistant glucan and hydrogenated resistant glucan, in rats and humans

Abstract

BackgroundResistant glucan (RG) and hydrogenated resistant glucan (HRG) are new dietary fiber materials developed to decrease the risk of metabolic syndrome and lifestyle-related diseases. We investigated the metabolism and bioavailability of RG and HRG using rats and humans.MethodsPurified RG and HRG were used as test substances. After 25 Wistar male rats (270 g) were fed with an experimental diet (AIN93M diet with the cellulose replaced by β-corn starch) ad libitum for 1 week, they were used for the experiment involving blood collection and circulating air collection. Ten participants (5 males, 22.5 y, BMI 20.4 kg/m2; 5 females, 25.8 y, BMI 20.9 kg/m2) voluntarily participated in this study. The study was carried out using a within-subject, repeated measures design. Effects of RG and HRG on the response for blood glucose and insulin and hydrogen excretion were compared with those of glucose and a typical nondigestible and fermentable fructooligosaccharide (FOS) in rats and humans. Available energy was evaluated using the fermentability based on breath hydrogen excretion.ResultsWhen purified RG or HRG (400 mg) was administered orally to rats, blood glucose and insulin increased slightly, but less than when glucose was administration (P < 0.05). Hydrogen started to be excreted 120 min after administration of RG with negligibly small peak at 180 min, thereafter excreted scarcely until 1440 min. Hydrogen excretion after HRG administration showed a larger peak than RG at 180 min, but was markedly less than FOS. RG and HRG were excreted in feces, but not urine. When purified RG or HRG (30 g) were ingested by healthy humans, blood glucose and insulin levels increased scarcely. Breath hydrogen excretion increased slightly, but remarkably less than FOS. Ingestion of purified RG or HRG (5 g) to evaluate available energy, increased scarcely glucose and insulin levels and breath hydrogen excretion. Available energy was evaluated as 0 kcal/g for purified RG and 1 kcal/g for HRG.ConclusionThe bioavailability was very low in both humans and rats, because oligosaccharide of minor component in purified RG and HRG was metabolized via intestinal microbes but major components with higher molecular weight were metabolized scarcely. Moreover, the ingestion of 30 g of RG or HRG did not induce apparent acute side effects in healthy adults. RG and HRG might potentially be used as new dietary fiber materials with low energy.

Effects of 1,5-anhydroglucitol on postprandial blood glucose and insulin levels and hydrogen excretion in rats and healthy humans

“…voluntarily participated in this study. The exclusion criteria were a history of gastrointestinal diseases, carbohydrate malabsorption, diabetes, obesity or pulmonary disease (28)(29)(30)(31)(32) . The average value of the fasting blood glucose concentration of the subjects was 4•5 ± 0•23 mmol/l and was within the normal range.…”

“…The energy supplied to the subjects was 214-232 kJ (895-970 kcal), protein was 58-65 g and carbohydrate was about 1 g on experimental days. If needed, more tea or boiled eggs were given (28)(29)(30) . In addition, each subject was given a multivitamin tablet (Nature Made; Otsuka Pharmaceutical Co. Ltd) as a supplement every day during the experimental periods.…”

“…All test substances were given in a random order at intervals of 1 w or more. Experiments were carried out under the direction of a physician and with the methods used in our previous studies (28)(29)(30)(31)(32)34) . After overnight fasting, the subjects came to our laboratory in the morning, their health status was examined and their blood pressure and pulse rate were measured.…”

“…Then, 750 ml of end-expiratory gas was collected using a collection bag (Quintron Instrument Co. Inc.) and blood (120 μl) was collected from the fingertip using a heparinised haematocrit tube. After ingesting the test substance, end-expiratory gas was collected at 1-h intervals for 14 h (28)(29)(30) , and blood (120 μl) was collected at 30-min intervals for 180 min. After 1,5-AG (10 or 20 g) was ingested by healthy subjects (n 10), urine was collected between 0 and 3, 3-6 and 6-9 h following ingestion.…”

Considerations When Using Predictive Equations to Estimate Energy Needs Among Older, Hospitalized Patients: A Narrative Review

“…Furthermore, the majority of older adults have at least one chronic condition [4, 5], which may lead to greater susceptibility of hospital-acquired infections and other complications that further contributes to decline in function [6]. Malnutrition is also a prevalent issue within the health care setting that can contribute to functional decline [7], yet estimates suggest only half of malnourished patients are recognized and treated [8, 9]. In order to appropriately inform nutrition recommendations, an accurate assessment of a patient's energy needs is required.…”