Metabolic Profiling Reveals Differences in Plasma Concentrations of Arabinose and Xylose after Consumption of Fiber‐rich Pasta and Wheat Bread with a Differential Rate of Systemic Appearance of Starch‐derived Glucose in Healthy Men

Abstract

Consumption of starchy products with slowly digestible starch is implicated with a lower risk of metabolic diseases. Previously, it has been shown that pasta consumption resulted in a lower rate of appearance of exogenous glucose (RaE) and lower glucose clearance rate quantified with a dual isotope technique, which was in accordance with a lower insulin and GIP response after pasta intake. To get more insight in the acute metabolic consequences of the intake of products with differential rate of appearance of starch‐derived glucose, plasma metabolic profiles in 9 healthy men were analyzed after consumption of wheat bread and pasta, both enriched with wheat‐bran.Differences in postprandial responses of 134 plasma metabolites were analyzed using a GC‐MS ‐based metabolomic approach. Six samples were analyzed per subject; one baseline sample and 30, 60, 90, 120 and 180 min after consumption. A two‐way ANOVA was used to analyze the effect of time, treatment, and their interaction. Additionally, pathway analysis was performed.The observed differences occurred primarily in pathways related to protein and energy metabolism. Profiles of various amino acids had similar postprandial patterns and showed lower and attenuated responses after pasta, which could be explained by a slower absorption (parallel to the lower RaE) as well as the lower insulin response after pasta. Metabolites of glucose metabolism showed similar profiles as RaE, whereas metabolites of lipid metabolism were suppressed for a longer time after pasta intake. Remarkable higher plasma concentrations of arabinose (A) and xylose (X) after consumption of pasta were found. A and X are derived from arabinoxylans (AX), which are important components of wheat bran. The higher bioavailability of A and X coincided with a lower rate of appearance of glucose and amino acids. This is possibly due to higher viscosity of AX in the small intestine after pasta consumption, which is hindering absorption. The lower rate of glucose appearance is thus apparently not caused by slow starch digestion, but by slow absorption of starch‐derived glucose. As both food products contained the same amount of AX, different methods of processing may explain the difference in viscosity. It is speculated that the higher bioavailability of A and X after pasta is due to higher degradation of AX by small intestinal microbiota, facilitated by higher viscosity of AX after pasta. These results suggest that also wheat bran, depending of processing, may increase viscosity of the meal bolus in the small intestine and interfere with macronutrient absorption, thereby influencing postprandial glucose and insulin response.Support or Funding InformationThe project was supported by UMCG, TNO, TIFN and ZON‐MW