Metabolic phenotypes and the gut microbiota in response to dietary resistant starch type 2 in normal-weight subjects: a randomized crossover trial

Lei Zhang,Peiyuan Yin,Guangyu Wu,Qichen Fang,Li Shen,Yunfeng Xiao,Yang Ouyang,Jing Zhang,Jianping Ye,Weiping Jia,Yueqiong Ni,Guowang Xu,Gianni Panagiotou,Lingling Qian,Huating Li

doi:10.1038/s41598-018-38216-9

Abstract

Resistant starch (RS) has been reported to reduce body fat in obese mice. However, this effect has not been demonstrated in humans. In this study, we tested the effects of RS in 19 volunteers with normal body weights. A randomized, double-blinded and crossover design clinical trial was conducted. The study subjects were given either 40 g high amylose RS2 or energy-matched control starch with three identical diets per day throughout the study. The effect of RS was evaluated by monitoring body fat, glucose metabolism, gut hormones, gut microbiota, short-chain fatty acids (SCFAs) and metabolites. The visceral and subcutaneous fat areas were significantly reduced following RS intake. Acetate and early-phase insulin, C-peptide and glucagon-like peptide-1 (GLP-1) secretion were increased, and the low-density lipoprotein cholesterol (LDL-C) and blood urea nitrogen (BUN) levels were decreased after the RS intervention. Based on 16S rRNA sequencing, certain gut microbes were significantly decreased after RS supplementation, whereas the genus Ruminococcaceae_UCG-005 showed an increase in abundance. Other potential signatures of the RS intervention included Akkermansia, Ruminococcus_2, Victivallis, and Comamonas. Moreover, the baseline abundance of the genera Streptococcus, Ruminococcus_torques_group, Eubacterium_hallii_group, and Eubacterium_eligens_group was significantly associated with the hormonal and metabolic effects of RS. These observations suggest that a daily intake of 40 g of RS is effective in modulating body fat, SCFAs, early-phase insulin and GLP-1 secretion and the gut microbiota in normal-weight subjects.

Highlights

Dietary fibre is beneficial for the management of certain chronic diseases
The effects of Resistant starch (RS) on the gut microbiota were reported in obese patients with dysbiosis and in healthy human subjects[13,14], its effects on body fat were not reported in those studies
Intra-abdominal visceral and abdominal subcutaneous fat were significantly reduced by taking RS at 40 g/d in the 4-week study

Summary

Introduction

Dietary fibre is beneficial for the management of certain chronic diseases. Resistant starch (RS) is a prebiotic dietary fibre that is subject to fermentation by the gut microbiota in the intestine[1,2]. Its effects have not been carefully tested in human subjects, especially in those with normal body weights. The effects of RS on the gut microbiota were reported in obese patients with dysbiosis and in healthy human subjects[13,14], its effects on body fat were not reported in those studies. We tested the effects of 40 g/d of RS on 19 normal-weight subjects on a controlled diet in a double-blinded and crossover clinical trial. The effects of RS on body fat, glucose, fatty acid metabolism, and the gut microbiota were examined. Our results suggest that RS reduces visceral and subcutaneous fat in normal-weight subjects and induces beneficial changes in gut hormones and the microbiota

Methods

Results

Conclusion