Nutrients recently published a special issue entitled “Dietary Fructose and Glucose: The Multifaceted Aspects of their Metabolism and Implication for Human Health” which included fifteen papers relating to these monosaccharides. Staff has identified articles of interest to the Working Group and has provided a summary of each, including points of consideration as necessary.
The article “The Effect of Short-Term Dietary Fructose Supplementation on Gastric Emptying Rate and Gastrointestinal Hormone Responses in Healthy Men” by Yau, et al., describes findings from a research study in which 10 healthy men (mean ± standard deviation, age 26 ± 7 years, body mass index 25.3 ± 3.1 kg/m2, and estimated body fat 23.2% ± 8.1%) were provided beverages to consume for 3 days prior to evaluating the gastric emptying rate and gastrointestinal hormone responses to equicaloric fructose and glucose solutions. Participants were asked to consume either four 500 mL bottles of water (control trials) or four 500 mL solutions, each containing 30 g fructose (supplement trials) per day over a 3-day dietary maintenance period followed by experimental trials that included ingestion of 595 mL of a fructose solution (36 g dissolved in water and prepared to a volume of 600 mL) or an equicaloric glucose monohydrate solution (39.6 g dissolved in water and prepared to a volume of 600 mL). Following beverage intake, blood samples were collected at 10, 20, 30, 45 and 60 min post ingestion and ratings of appetite (hunger, fullness, prospective food consumption) were assessed at baseline and at 10-min intervals following drink ingestion for 60 min. Gastric emptying was assessed using the 13C-acetate breath method and breath samples were analyzed by non-dispersive infra-red spectroscopy. Concentrations of glucose, fructose, lactate, triglyceride, acylated ghrelin, insulin, GIP, leptin, and total GLP-1 were reported. Gastric emptying rates for fructose ingestion was accelerated after the 3-day period of dietary fructose supplementation compared to the water control (Fructose Control, 59 ± 13 min vs. Fructose supplement, 51 ± 10 min; p = 0.004) while gastric emptying T1/2 for glucose ingestion did not change with fructose supplementation (Glucose Control, 75 ± 18 min vs. Glucose Supplement, 68 ± 16 min; p = 0.245). The gastric emptying results of this study are in agreement to previous findings showing a monosaccharide-specific adaptation in gastric emptying rate following short-term dietary supplementation of fructose. While differences in gastric emptying would be expected to impact glycemic and insulinemic responses neither serum glucose or fructose differed among treatments and similar lactate concentrations also suggest that the capacity to metabolize fructose into glucose is not altered. The authors conclude “The adaptability of the gut and the mechanisms responsible for this should be further investigated with both short- and longer-term studies, along with the subsequent effects on food intake.”