Background The human gut is home for plethora of microbes including prokaryotic, eukaryotic and other microorganisms. During ageing, imbalances in the gut microbiota are associated with significant phenotypic effects for the host such as the development of metabolic disorders like changes in serum lipids levels, including general physiological decline. However, the presence of fungal communities and their possible association with host health are poorly understood. Therefore, we aim to elucidate trajectory for the progression of atherogenic dyslipidemia during ageing.

Methods The interplay between dietary intake, gut microbiota composition, plasma and fecal metabolome and clinical measurements were investigated. The gut bacterial and fungal compositions were determined by high-throughput sequencing of V3 region of 16S rRNA and internal transcribed spacer (ITS2) gene amplicons, respectively. The plasma and fecal metabolomes were determined by GC-TOF-MS. Finally, the dietary intake records and the anthropometric/body-composition measurements at baseline were taken from 75 senior citizens aged 65 years old and above (69.57 ± 3.64).

Results At phyla, the gut is home to three main eukaryotic, namely Ascomycota, Basidiomycota and Zygomycota, with genera Penicillium, Candida, and Aspergillus being particularly common. Hypertriglyceridemia group (HG) was associated with low species richness as compared to Normotryglyceridemia group (NG), indicate by α-diversity - Observed species, PD whole tree and Chao1 indices; p <0.05, and Bray-Curtis dissimilarity matrix-based analysis showed significant (p <0.05) clustering according to fasting levels of circulating plasma triglycerides (Tg). Inversely, the hypertriglyceridemia clustering based on the prokaryotic component was not observed among both groups. Higher levels of Tg significantly associates with increased relative abundance of genus Penicillium, possibly mediated by a higher dietary fat intake (ANOVA,p <0.05), and Aspergillus and Guehomyces were positively associated with short-chain fatty acids (SCFAs) groups.

Conclusions Collectively, these findings suggest that the gut mycobiome dysbiosis is associated with hypertriglyceridemia, a known risk factor for the development of cardiovascular disease among the elders.