Managing diabetes with probiotics and synbiotics

By Dr. Sanchari Sinha Dutta, Ph.D.Reviewed by Benedette Cuffari, M.Sc.Apr 16 2024

In a recent study published in the journal Clinical Nutrition, researchers reviewed data obtained from randomized clinical trials (RCTs) that have investigated the effects of prebiotics and synbiotics on glycemic control in patients with type 1 and type 2 diabetes (T1D).

Study: Probiotics and synbiotics for glycemic control in diabetes: A systematic review and meta-analysis of randomized controlled trials. Image Credit: Helena Nechaeva / Shutterstock.com

Advancing diabetes treatment methods

The global prevalence of both T1D and T2D continues to rise each year. Current estimates indicate that about 465 million adults between 20 and 79 years of age throughout the world are currently living with diabetes, with up to 578 and 700 million projected to be diagnosed by 2030 and 2045, respectively.

Despite recent advancements in anti-diabetic treatments, a significant proportion of patients continue to experience suboptimal glycemic control. Among various novel strategies for glycemic control, targeting the gut microbiota through probiotics and other therapeutics has been proposed as a novel approach to managing diabetes.

In T1D, which refers to insulin deficiency, and T2D, which occurs due to insulin resistance, specific alterations in the composition and function of the gut microbiota, which are collectively referred to as gut dysbiosis, have been reported. Probiotics are live microorganisms are associated with numerous health benefits through their ability to restore gut microbiota homeostasis, improve the integrity of the gastrointestinal (GI) tract, and reduce inflammation.

Synbiotics, which are combinations of probiotics and prebiotics, are also gaining attention in the field of diabetes management to increase the growth and functions of beneficial microorganisms present within the GI tract.

Study design

For the current review, researchers utilized various electronic databases to identify relevant RCTs that included adult patients with diabetes who were being treated with probiotics or synbiotics in addition to their specific anti-diabetic treatments. RCTs that compared these interventions with other treatments, placebo, or standard diabetic treatment in the context of glycemic control were included in the meta-analysis.

A total of 41 RCTs, which involved a total of 2,991 patients, were included in the final analysis. The different parameters that were assessed to measure glycemic control included glycated hemoglobin (HbA1C), fasting plasma glucose, and serum insulin levels.

Study findings

The current meta-analysis revealed that probiotic and synbiotic supplementation is associated with significant improvements in fasting plasma glucose, serum insulin, and HbA1C levels.  

The sub-group analysis demonstrated that the efficacy of tested interventions varies between the type of microbial strains used and between countries.

Multispecies formulations were associated with superior effectiveness in improving HbA1C levels compared to monospecies formulations. This observation emphasizes the importance of multispecies formulations in achieving persistent glycemic control.

Comparatively, monospecies formulations were associated with more consistent effects across different outcomes, thus suggesting their broader applicability in the management of diabetes. Synbiotics were also associated with greater efficacy than probiotics in improving serum insulin levels.

Regarding the different types of bacterial species used in probiotic formulations, certain Lactobacillus strains and Bifidobacterium lactis were associated with pronounced effects, especially in multispecies formulations. Thus, the therapeutic efficacy of probiotic interventions for managing diabetes may be strain-specific.

Study limitations

Moderate heterogeneity was observed across the selected RCTs, which could be attributed to variations in the study designs, participants’ characteristics, and intervention protocols. Importantly, this heterogeneity may restrict the generalizability of the findings.  

Additionally, most of the selected RCTs were conducted in Iran, thereby restricting the generalizability of these findings to other populations with different genetic and environmental factors.

The current study also could not separately determine the efficacy of these interventions for each type of diabetes. T1D and T2D have distinct pathophysiologies, treatment modalities, and therapeutic outcomes; therefore, the effects of both probiotics and synbiotics on glycemic control may vary between patients with these different types of diabetes.

Conclusions

The study findings emphasize the potential importance of both probiotics and synbiotics as complementary interventions in diabetes management. Nevertheless, future studies that consider multiple variables, such as strain types and geographical factors, are needed to better understand the efficacy of probiotics and synbiotics in the management of T1D and T2D.

While probiotics and synbiotics show promise as add-on therapies, they are not a standalone solution in diabetes care…Incorporating probiotics or synbiotics into treatment plants as complementary might be a viable strategy for enhancing glycemic control, although more tailored research is needed.”