The modulatory effect of pea resistant starch on hyperlipidemia in high fat diet-induced obese mice is related to their supramolecular structural features.

Abstract

Background: Resistant starch (RS) has gained attention for its potential in managing metabolic disorders. This study aimed to compare the supramolecular structure and anti-hyperlipidemia effects of RS isolated from native pea starch (NP-RS) and autoclaved pea starch (AP-RS) in high-fat diet (HFD)-induced obese mice. The structural characteristics of NP-RS and AP-RS were analyzed, and their impacts on obesity-related conditions, gene expression, and gut microbiota were evaluated.

Results: The crystalline polymorph of AP-RS shifted from a C-type to a B-type, with significantly higher long- and short-range crystallinity and double helix levels compared to NP-RS, as determined by X-ray diffraction and solid-state carbon-13 nuclear magnetic resonance (¹³C-NMR) analyses. Small-angle X-ray scattering analysis demonstrated a higher α value for AP-RS, suggested enhanced structural compactness. In vivo experiments revealed that both NP-RS and AP-RS alleviated obesity-related conditions, including body weight control, oxidative stress inhibition, inflammatory response alleviation, and liver function regulation, with AP-RS exhibiting more pronounced effects. These effects were associated with the down-regulation of gene expression levels of liver type glycogen synthase-2 (GYS2), enzyme glycogenin-1 (GYG1), sterol regulatory element binding protein-1 (SREBP-1), fatty acid synthase (FAS) and the up-regulation of insulin induced gene-1 (Insig-1), Insig-2, and acetyl-CoA oxidase 1 (Acox1). Additionally, 16S rDNA sequencing analysis indicated that both NP-RS and AP-RS mitigated HFD-induced gut dysbiosis by increasing the abundance of beneficial bacteria, such as Allobaculum and Bifidobacterium.

Conclusion: The resistant characteristics of AP-RS, marked by increased crystallinity and a higher content of double helices, exhibit greater stability. This stability likely leads to differences in accessibility and fermentability between NP-RS and AP-RS substrates in vivo across various intestinal segments, resulting in different physiological responses in obese mice. These findings highlight the potential for designing novel RS-based supplements with tailored metabolic effects to promote health benefits. © 2025 Society of Chemical Industry.