Introduction

Probiotic fermented milk could play a valuable role in helping to tackle Type 2 diabetes. Although yet to be confirmed, early research suggests that consuming fermented milk may be linked to improvements in several key health markers of Type 2 diabetes mellitus (T2DM), including indicators of blood sugar control (1).

As such, consuming fermented milk products may offer a helping hand in delaying the progression and reducing complications of this chronic disease.

It’s welcome news for scientists as they struggle to stem the tide of the diabetes epidemic that is sweeping across the world and placing a huge burden on individuals and society as a whole.

What is probiotic fermented milk?

Fermented milk products, such as yogurt or kefir, contain live bacteria used in fermentation that may improve gut health. They can also be enriched with probiotics – additional live bacteria that confer further health benefits. Fermented milk products have properties that help the survival and growth of these probiotics in the gut (2).

Scientists have proposed that improving gut health might help manage T2DM by affecting how the body processes sugars and fats. Mounting evidence suggests that composition of the gut bacteria may have a role in the development of T2DM by influencing insulin sensitivity, inflammatory regulation, and lipid metabolism (3). Modulating the composition of the gut microbiota through consumption of probiotics has therefore been proposed as a potential therapy for T2DM.

With this in mind, researchers set out to investigate whether probiotic fermented milk can improve key health indicators in people with T2DM, including measures of glucose and lipid metabolism and inflammatory markers. They analysed the results of ten randomised controlled trials studying the effects of probiotic-enriched fermented milk in over 250 adults with T2DM.

Probiotic fermented milk has potential to benefit the health of people with T2DM

Based on their analysis of randomised controlled trial results, the meta-analysis concluded that probiotic-enhanced fermented milk has the potential to have positive impacts on certain health markers in people with T2DM, when compared with conventional fermented milk products.

• Blood sugar control:
  Consuming probiotic fermented milk was associated with significantly reduced markers of blood sugar levels, including a fall in fasting plasma glucose by an average of 17 mg/dL and glycosylated haemoglobin (HbA1c) by 0.5%. These reductions suggest improvements in blood sugar management.
• Cholesterol levels:
  Total cholesterol levels were reduced significantly by 5.15 mg/dL in association with fermented milk consumption, indicating potential cardiovascular health benefits for people with T2DM. The effects on other lipid markers, such as triglycerides, low-density lipoprotein (LDL) cholesterol and high-density lipoprotein (HDL) cholesterol, were not significant.
• Inflammation reduction:
  The analysis found a significant decrease in levels of the inflammatory marker C-reactive protein (CRP), suggesting a potential anti-inflammatory effect associated with probiotic fermented milk. This could be a valuable finding, since inflammation plays a crucial role in the progression of T2DM and the development of complications (4).

Beneficial effects of probiotic fermented milk in T2DM may be mediated through the gut microbiota

The exact mechanisms behind the beneficial effects of probiotic fermented milk in people with T2DM are not fully understood and probably involve several factors. The authors highlight that one explanation for such benefits might be the change to the composition of the gut microbiota caused by probiotics.

An imbalance in gut microbiota composition is common in people with T2DM, and can lead to increased intestinal permeability, allowing bacterial toxins to enter the circulation, causing inflammation and raising levels of cholesterol and blood sugar (5,6). Probiotics can restore balance to the gut microbiota by promoting the growth of beneficial bacteria and inhibiting the number of harmful bacteria (7,8).

What further research is needed?

While probiotic fermented milk shows promise in helping to manage blood sugar, cholesterol, and inflammation in people with T2DM, further research is needed to confirm these benefits.

The number of studies and participants included in the analysis was relatively small, which limits the strength of the conclusions. The trials included also varied in terms of their study design and duration, as well as the probiotic strains and comparators used, making it difficult to compare results accurately across studies. The researchers propose that larger, more standardized trials are needed to determine whether probiotic fermented milk can become a reliable part of T2DM management.

“The present findings provide a crude indication of the potential benefits of probiotic fermented milk supplementation in improving glucose and lipid metabolism and inflammation in patients with T2DM. However, more robust evidence is needed to determine the clinical significance of probiotic fermented milk in the management of T2DM.”

Zhong H, et al., 2024

References

1. Zhong H, Wang L, Jia F, et al. Effect of Probiotic Fermented Milk Supplementation on Glucose and Lipid Metabolism Parameters and Inflammatory Markers in Patients with Type 2 Diabetes Mellitus: A Meta-Analysis of Randomized Controlled Trials. Biology (Basel). 2024 Aug 21;13(8):641. doi: 10.3390/biology13080641. PMID: 39194579
2. Khorshidian N., Yousefi M., Mortazavian, A.M. Fermented milk: The most popular probiotic food carrier. Adv. Food Nutr. Res. 2020, 94, 91–114
3. Gurung M., et al. Role of gut microbiota in type 2 diabetes pathophysiology. EBioMedicine 2020, 51, 102590
4. Goldberg R.B. Cytokine and cytokine-like inflammation markers, endothelial dysfunction, and imbalanced coagulation in development of diabetes and its complications. J. Clin. Endocrinol. Metab. 2009, 94, 3171–3182
5. Zhou Z., Sun B., Yu D., Zhu C. Gut Microbiota: An Important Player in Type 2 Diabetes Mellitus. Front. Cell. Infect. Microbiol. 2022, 12, 834485
6. Cani P.D., et al. Metabolic endotoxemia initiates obesity and insulin resistance. Diabetes 2007, 56, 1761–1772
7. Wang Y., Dilidaxi D., Wu Y., Sailike J., Sun X., Nabi X.H. Composite probiotics alleviate type 2 diabetes by regulating intestinal microbiota and inducing GLP-1 secretion in db/db mice. Biomed. Pharmacother. 2020, 125, 109914
8. Markowiak-Kopec P., Slizewska K. The Effect of Probiotics on the Production of Short-Chain Fatty Acids by Human Intestinal Microbiome. Nutrients 2020, 12, 1107