Biology subjects

Wilhelmi de Toledo, F.

Publications and source records attributed to Wilhelmi de Toledo, F..

2 recordsLinked to original sources

bioRxiv2026

Effects of long-term fasting: longitudinal epigenetic responses in humans

Prolonged fasting induces marked metabolic adaptations, but whether such time-limited yet intensive interventions engage molecular processes related to biological aging in humans remains unclear. To address this, we investigated physiological and epigenetic responses to a 12-day medically supervised fasting intervention with longitudinal follow-up in 32 participants. Fasting elicited coordinated systemic physiological changes across metabolic and hematological parameters, with partial persistence at one month. Genome-wide DNA methylation analyses revealed modest but detectable CpG-level changes, primarily emerging at follow-up and distributed across genomic contexts. In parallel, epigenetic aging clocks showed clock-specific and time-dependent responses, with substantial inter-individual variability. Lower baseline epigenetic age acceleration was consistently associated with greater fasting-induced weight loss, suggesting a link between epigenetic state and metabolic responsiveness. Together, these findings indicate that prolonged fasting induces coordinated physiological adaptations alongside structured changes in epigenetic aging measures that are not captured by conventional clinical biomarkers. This study highlights epigenetic clocks as integrative molecular readouts for probing aging-related responses to short-term metabolic interventions, while also delineating their current interpretive limits.

genomics↗

bioRxiv2024

Long-term fasting remodels gut microbial metabolism and host metabolism

Long-term fasting has become a promising research subject for its potential of treating and preventing metabolic diseases. However, little is known about its impact on the functional capacity of the gut microbiome and the combined effect on the serum metabolome. Here, we demonstrate extensive remodelling of the gut microbial ecosystem in humans (n=92) after an average of 9.8 days of fasting ([~]250 kcal / day). Fasting transiently affected the relative abundance of the majority of bacterial species (306 decreased and 210 increased out of 772). Species changes could largely be explained by their genomic repertoire of carbohydrate-active enzymes (CAZymes), which were investigated here for the first time. Fasting induced extensive abundance changes in CAZyme families, depleting families with dietary fibre substrates and increasing families with host-derived glycan substrates. Likewise, we observed extensive changes in the serum metabolome, with 382 out of 721 metabolites significantly affected (246 increased and 136 decreased). In-depth metagenome-metabolome co-variation analysis suggested Oscillibacter species to be key producers of indole-3-propionic acid, a crucial metabolite for cardiometabolic health. Together, our results provide an unprecedented view on the impact of long-term fasting on gut microbiome composition and function.

microbiology↗