Tsuneyuki Oku, Kenichi Tanabe, Norihisa Hamaguchi, Fumio Shimura and Sadako Nakamura
Institute of Food, Nutrition & Health, Jumonji University, Japan
Resistant glucan (RG) and hydrogenated resistant glucan (HRG) are new dietary fibre materials developed to decrease the risk of metabolic syndrome and lifestyle-related diseases. This study investigated the bioavailability and available energy of purified RG and HRG in rats and humans. The human study used a within-subject, repeated measures design. Effects of RG and HRG on blood glucose and insulin levels and hydrogen excretion were compared with those of resistant maltodextrin (RMD) and fructooligosaccharide (FOS). Available energy was evaluated from breath hydrogen excretion. When rats ingested RG or HRG (400 mg), blood glucose and insulin levels increased slightly. Hydrogen started to excrete about 120 min after administration of RG with a small peak at 180 min, thereafter scarcely excreted until 1440 min. Hydrogen excretion after HRG administration showed a larger peak than RG at 180 min, but much smaller than FOS. RG and HRG were excreted in faeces, but not urine. When RG or HRG (30 g) was ingested by humans, glucose and insulin levels increased scarcely. Breath hydrogen excretion increased slightly, but much less than FOS. After RG or HRG (5 g) ingestion to evaluate available energy, glucose and insulin levels and breath hydrogen excretion increased scarcely. Available energy was 0 kcal/g for RG and HRG. Although oligosaccharides (minor component of RG and HRG) were only slightly digested and fermented slightly, high molecular weight carbohydrates (main component) were digested scarcely and fermented barely in humans. RG and HRG could be used as new dietary fibre materials with low energy.
Keywords: Bioavailability, available energy, dietary fibre materials, resistant glucan, hydrogenated resistant glucan.