Intermittent Fasting Induces Weight Loss, but the Effects on Cardiometabolic Health are Modulated by Energy Balance

Gut microbiome in diabetic retinopathy: A systematic review and meta-analysis

CONTEXT

Changes in the gut microbiome are linked with Type 2diabetes mellitus (T2DM) development, but alterations in patients with diabetic retinopathy (DR) are still being debated.

OBJECTIVE

To investigate the differences in biodiversity and relative abundance of gut microbiome between patients with DR and T2DM.

METHODS

A comprehensive search was performed in five electronic databases (PubMed, EMBASE, Cochrane Central Register of Controlled Trials, Web of Science, and CNKI) from the inception of each database through to August 2023. The standardized mean difference (SMD) and its 95% confidence interval (CI) were estimated using Stata 15.1. Furthermore, the alpha diversity index and relative abundance of the gut microbiome were calculated. The Egger test determined publication bias in the literature.

RESULTS

Seven case-control studies were included in the final dataset, comprising 195 patients with DR and 211 patients with T2DM. Compared to T2DM patients, patients in the DR group had a reduced but not significantly different α-diversity. The analysis of microbial composition at the phylum level revealed a marked increase in the relative abundance of Bacteroidetes(ES = 23.27, 95%CI[8.30, 38.23], P = 0.000) and a decline in Firmicutes(ES = 47.05, 95%CI[36.58, 57.52], P = 0.000), Proteobacteria (ES = 11.08, 95%CI[6.08, 16.07], P = 0.000) and Actinobacteria (ES = 10.43, 95%CI[1.64, 19.22], P = 0.001) in patients with DR when compared to those with T2DM.

CONCLUSIONS

An association exists between alterations in the gut microbiome of T2DM and the development and progression of DR. This suggests that re-establishing homeostasis of the gut microbiome could be a potential way to prevent or treat DR and requires further confirmation in future studies.

REGISTRATION DATABASE

Prospero.

REGISTRATION NUMBER

CRD42023455280.

Facilitators and barriers of infectious diseases surveillance activities: lessons from the Global Polio Eradication Initiative - a mixed-methods study

OBJECTIVES

To document lessons from the Global Polio Eradication Initiative (GPEI) by determining factors associated with successful surveillance programme globally as well as at national and subnational levels. The process of conducting surveillance has been previously recognised in the literature as important for the success of polio surveillance activities.

DESIGN

A cross-sectional survey with closed and open-ended questions.

SETTINGS

Survey of persons involved in the implementation of surveillance activities under the GPEI at the global level and in seven low-income and middle-income countries.

PARTICIPANTS

Individuals (n=802) with ≥12 months of experience implementing surveillance objective of the GPEI between 1988 and 2019.

MAIN OUTCOME MEASURES AND METHODS

Quantitative and qualitative analyses were conducted. Logistic regression analyses were used to assess factors associated with implementation process as a factor for successful surveillance programme. Horizontal analysis was used to analyse qualitative free-text responses on facilitators and barriers identified for conducting surveillance activities successfully.

RESULTS

Overall, participants who reported challenges relating to GPEI programme characteristics had 50% lower odds of reporting implementation process as a factor for successful surveillance (adjusted OR (AOR): 0.50, 95% CI: 0.29 to 0.85). Challenges were mainly perceptions of external intervention source (ie, surveillance perceived as 'foreign' to local communities) and the complexity of surveillance processes (ie, surveillance required several intricate steps). Those who reported organisational challenges were almost two times more likely to report implementation process as a factor for successful surveillance (AOR: 1.89, 95% CI: 1.07 to 3.31) overall, and over threefolds (AOR: 3.32, 95% CI: 1.14 to 9.66) at the national level.

CONCLUSIONS

Programme characteristics may have impeded the process of conducting surveillance under the GPEI, while organisational characteristics may have facilitated the process. Future surveillance programmes should be designed with inputs from local communities and frontline implementers.

Mental and Behavioural Responses to Bahá'í Fasting: Looking behind the Scenes of a Religiously Motivated Intermittent Fast Using a Mixed Methods Approach

Background/Objective: Historically, fasting has been practiced not only for medical but also for religious reasons. Bahá’ís follow an annual religious intermittent dry fast of 19 days. We inquired into motivation behind and subjective health impacts of Bahá’í fasting. Methods: A convergent parallel mixed methods design was embedded in a clinical single arm observational study. Semi-structured individual interviews were conducted before (n = 7), during (n = 8), and after fasting (n = 8). Three months after the fasting period, two focus group interviews were conducted (n = 5/n = 3). A total of 146 Bahá’í volunteers answered an online survey at five time points before, during, and after fasting. Results: Fasting was found to play a central role for the religiosity of interviewees, implying changes in daily structures, spending time alone, engaging in religious practices, and experiencing social belonging. Results show an increase in mindfulness and well-being, which were accompanied by behavioural changes and experiences of self-efficacy and inner freedom. Survey scores point to an increase in mindfulness and well-being during fasting, while stress, anxiety, and fatigue decreased. Mindfulness remained elevated even three months after the fast. Conclusion: Bahá’í fasting seems to enhance participants’ mindfulness and well-being, lowering stress levels and reducing fatigue. Some of these effects lasted more than three months after fasting.

A Muscle-Centric Perspective on Intermittent Fasting: A Suboptimal Dietary Strategy for Supporting Muscle Protein Remodeling and Muscle Mass?

Muscle protein is constantly “turning over” through the breakdown of old/damaged proteins and the resynthesis of new functional proteins, the algebraic difference determining net muscle gain, maintenance, or loss. This turnover, which is sensitive to the nutritional environment, ultimately determines the mass, quality, and health of skeletal muscle over time. Intermittent fasting has become a topic of interest in the health community as an avenue to improve health and body composition primarily via caloric deficiency as well as enhanced lipolysis and fat oxidation secondary to attenuated daily insulin response. However, this approach belies the established anti-catabolic effect of insulin on skeletal muscle. More importantly, muscle protein synthesis, which is the primary regulated turnover variable in healthy humans, is stimulated by the consumption of dietary amino acids, a process that is saturated at a moderate protein intake. While limited research has explored the effect of intermittent fasting on muscle-related outcomes, we propose that infrequent meal feeding and periods of prolonged fasting characteristic of models of intermittent fasting may be counter-productive to optimizing muscle protein turnover and net muscle protein balance. The present commentary will discuss the regulation of muscle protein turnover across fasted and fed cycles and contrast it with studies exploring how dietary manipulation alters the partitioning of fat and lean body mass. It is our position that intermittent fasting likely represents a suboptimal dietary approach to remodel skeletal muscle, which could impact the ability to maintain or enhance muscle mass and quality, especially during periods of reduced energy availability.

The Gut-Eye Axis: Lessons Learned from Murine Models

A healthy gut microbiota is essential in maintaining the human body in a homeostatic state by its functions in digestion and immune tolerance. Under states of aberrant microbial composition or function (dysbiosis), the gut microbiota induces systemic inflammation that can lead to the onset of many diseases. In this review, we describe some evidence, largely from rodent studies, that supports the possible role of a dysbiotic gut microbiota in the onset and exacerbation of ocular diseases, primarily diabetic retinopathy, age-related macular degeneration, choroidal neovascularization, and uveitis. Furthermore, we examine several potential therapeutic measures that show promise in restoring the gut microbiota to a eubiotic state, preventing the aforementioned disease pathologies.