Effects of one month of intermittent fasting on the blood microbiome in healthy volunteers (OMIF): A randomized controlled crossover study protocol

This is the authors' abstract. We don't add key points for this paper.

BACKGROUND: It is hypothesized that the presence of microorganisms in the gut is reflected in circulating blood through small DNA fragments resulting from the degradation of these organisms. Cross-sectional studies have not yet provided a definitive answer regarding the validity of this hypothesis, and the potential presence of a so-called common blood-microbiome remains highly controversial. Both bioinformatical pipelines (which may produce false-positive results) and environmental contamination may obscure the less than 5 % microbial DNA that is postulated to be present within the total blood DNA. METHOD/DESIGN: This study aims to validate the existence of the blood microbiome using one month of intermittent fasting (OMIF). Through a prospective, randomized, controlled cross-over trial, we will evaluate the effect of OMIF on the composition and function of the blood microbiome in healthy volunteers, with secondary outcomes on clarifying the relationship between the gut and blood microbiome. Healthy volunteers aged 18-65 will be enrolled. All volunteers will undergo OMIF, a washout period and an ad libitum diet for another month, with the order of the interventions assigned randomly. We will assess the dynamics in blood microbiome in response to OMIF versus those seen during an ad libitum diet, using shotgun sequencing. Physiological changes will be monitored A dietary recall interview will be conducted during the trial to evaluate energy intake, and movement data collected from Health App will be used to assess changes in physical activity. CONCLUSION: If successful, this trial provides a proof-of-concept study documenting the existence of a bona fide blood microbiome. CLINICAL TRIAL REGISTRATION: NCT06678516.