Can fasting improve diabetes outcomes? Ramadan offers insights

Discover how religious fasting reveals powerful yet fleeting health benefits, emphasizing the importance of consistent dietary strategies for managing type 2 diabetes.

In a recent study published in the journal Clinical Nutrition Open Science, researchers used the month-long Ramadan fasting period as a proxy to investigate the impacts of intermittent fasting (IF) on several aspects of liver health, gut microbiota composition, and metabolic biomarkers, particularly in patients living with type 2 diabetes (T2DM).

Study findings indicate that IF can promote substantial weight loss in this cohort and improve liver health. Notably, calorie intake was consistent across fasting and non-fasting groups, underscoring that these improvements were driven by the fasting pattern rather than reduced calorie consumption. However, these improvements were found to be temporary, with post-fasting increases in liver apoptosis marker M30 levels observed.

Together, this study contributes to our understanding of the benefits and caveats of IF and similar weight-loss dietary regimes, paving the way for potentially optimized diet-based anti-T2DM interventions.

Background

Intermittent fasting (IF) is a dietary plan that involves alternating periods of ad libitum eating with extended fasting (energy deficit) periods.

First developed as a weight-loss dietary intervention, IF is increasingly popular amongst health-conscious individuals and those aiming to alleviate unwanted weight gain.

While observed to be highly successful in achieving weight targets and improving obesity-associated comorbidity outcomes, a mechanistic understanding of the program remains elusive.

Intermittent fasting is a relatively recent concept. However, similar fasting patterns have been followed across several religions, including Lent in Christianity and the Holy Month of Ramadan in Islam.

Ramadan, in particular, requires Muslim believers to abstain from food and beverage consumption between sunrise and sunset. Following sunset, food and drinks may be consumed ad libitum. Ramadan, hence, presents an ideal opportunity to investigate the impacts of IF-like fasting patterns on medical and physiological outcomes.

Type 2 diabetes mellitus (T2DM) patients are a target group of IF interventions, with previous research suggesting that these interventions can promote weight loss compared to ad libitum eating patterns, albeit without affecting glycemic homeostasis. This study further investigated whether such interventions influence other T2DM-related parameters, such as liver health and gut microbiota composition.

Unfortunately, controlled investigations of the mechanisms underpinning these outcomes remain lacking. The effects of time-limited calorie intakes and their subsequent impacts on T2DM patients would allow clinicians and nutritionists to optimize their non-invasive T2DM treatment options, improving patient outcomes.

About the Study

Unwelcome weight gain has been reported to significantly alter the gut microbial composition, damage liver tissue, and trigger dysfunction in glucose homeostasis, which are hallmarks of T2DM genesis and progression.

The present study aims to unravel the impacts of short-term (4 weeks) IF fasting (herein, Ramadan fasting) on these hallmarks in a cohort of T2DM patients, using non-fasting T2DM patients as controls.

Study data were acquired from voluntary recruits from Bochum University Hospital Knappschaftskrankenhaus's Department of Internal Medicine. The study was conducted to coincide with the 2021 Ramadan season (12 April to 12 May) and included both fasting (n = 21) and non-fasting (n = 17) participants. Herein, fasting was defined as "abstinence from food and drinks from sunrise to sunset" (~14 hours fasting) interspersed with a 10-hour-long ad libitum meal interval. Participants with malignant disease or chronic inflammatory bowel syndrome were excluded from the study.

Data collection included blood and stool samples used for biochemical and gut microbial investigations. Biomarkers of liver function, such as M30 and adiponectin, were analyzed alongside metabolic and stress-associated markers. DNA extracted from participants' fecal samples was sequenced using the Illumina platform for high-throughput gut microbiome characterization (composition and relative abundance). Liver steatosis was measured using transient elastography measurement (TEM) and bioelectrical impedance analysis (BIA).

Statistical comparisons between fasting and non-fasting participants were conducted using the Wilcoxon matched-pairs signed rank test, a robust non-parametric method.

Study Findings

Routine anti-T2DM medication (antidiabetics/Metformin/GLP-1 receptor agonists) was similar between both fasting and non-fasting cohorts, with both groups exhibiting elevated body mass indices (BMIs) and high liver fibrosis risk.

Biochemical assays revealed normal transaminase, alkaline phosphatase, and LDH levels in fasting participants. However, comparisons revealed significant weight loss in the fasting group compared to non-fasting participants over the 4-week study. This weight loss was accompanied by reductions in body fat mass, cortisol, and serum triglycerides, although cholesterol levels remained unchanged.

Notably, the liver tissue apoptosis marker (M30) showed substantially lower levels in the fasting group than in the non-fasting group. Gut microbiota analysis revealed an increase in species richness (Chao1 index), but broader shifts in bacterial composition were minimal.

Unfortunately, some of these observed benefits diminished rapidly after the fasting period, with post-fasting increases in M30 levels suggesting a transient benefit.

Conclusions

Intermittent fasting was demonstrated to have a positive effect on participants' weight loss, liver health, and gut microbial richness, validating its recommendation to T2DM patients. However, the durability of these effects appears limited, with non-compliance or cessation of fasting reversing key benefits.

Future research is required to ascertain patient-specific fasting-to-feeding ratios and investigate underlying mechanisms, including disruptions in circadian rhythms. This study marks a step forward in T2DM research and may form the basis for future non-pharmacological interventions against diabetes and its comorbidities.

Journal reference:

• Sydor, S., Engin, E., Wittek, S., Lemmer, P., Best, J., Steinmetz, M., Figge, A., Jähnert, A., Özcürümez, M., Broecker-Preuss, M., Syn, W., Canbay, A., & Manka, P. (2024). Religious Intermittent Fasting: Effects on Liver Health, Metabolic Markers, and Gut Microbiota in Type 2 Diabetes Patients. Clinical Nutrition Open Science. DOI: 10.1016/j.nutos.2024.11.001, https://www.sciencedirect.com/science/article/pii/S266726852400113X