Abstract
BACKGROUND: The relationship between consuming Thai desserts-predominantly composed of carbohydrates-and gut microbiome profiles remains unclear. This study aimed to evaluate the effects of consuming various Thai desserts with different GI values on the gut microbiomes of healthy volunteers. METHODS: This open-label, parallel randomized clinical trial involved 30 healthy individuals aged 18 to 45 years. Participants were randomly assigned to one of three groups: Phetchaburi's Custard Cake (192 g, low-GI group, n = 10), Saraburi's Curry Puff (98 g, medium-GI group, n = 10), and Lampang's Crispy Rice Cracker (68 g, high-GI group, n = 10), each consumed alongside their standard breakfast. Fecal samples were collected at baseline and 24 h post-intervention for metagenomic analysis of gut microbiome profiles using 16S rRNA gene sequencing. RESULTS: After 24 h, distinct trends in the relative abundance of various gut microbiota were observed among the dessert groups. In the high-GI dessert group, the abundance of Collinsella and Bifidobacterium decreased compared to the low- and medium-GI groups, while Roseburia and Ruminococcus showed slight increases. Correlation analysis revealed a significant negative relationship between sugar intake and Lactobacillus abundance in the medium- and high-GI groups, but not in the low-GI group. Additionally, a moderately negative association was observed between Akkermansia abundance and sugar intake in the high-GI group. These bacteria are implicated in energy metabolism and insulin regulation. LEfSe analysis identified Porphyromonadaceae and Porphyromonas as core microbiota in the low-GI group, whereas Klebsiella was enriched in the high-GI group, with no predominant bacteria identified in the medium-GI group. CONCLUSIONS: The findings suggest that Thai desserts with varying GI levels can influence specific gut bacteria, though these effects may be temporary.