From gut to glucose: the potential of probiotics in diabetes care

Type 2 diabetes is a metabolic disorder characterised by high blood sugar levels due to insulin resistance or insufficient insulin production. It's a growing global health concern. While diet, exercise and medication form the cornerstone of diabetes management, researchers are continually exploring new avenues to improve blood sugar control. One such area gaining traction is the use of probiotics that can alter gut and metabolic health. But can these tiny microorganisms make a meaningful difference for people with type 2 diabetes? That’s what I explore in this episode.

Links referred to in the podcast

• Review of the effects of probiotics on glucose control in T2DM https://pubmed.ncbi.nlm.nih.gov/39349104

Episode transcript
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Transcript

Type 2 diabetes is a metabolic disorder characterised by high blood sugar levels due to insulin resistance or insufficient insulin production. It's a growing global health concern. While diet, exercise and medication form the cornerstone of diabetes management, researchers are continually exploring new avenues to improve blood sugar control. One such area gaining traction is the use of probiotics that can alter gut and metabolic health. But can these tiny microorganisms make a meaningful difference for people with type 2 diabetes? Let’s dive into the latest research.

The gut microbiome is one of the hottest of research topics today. It seems almost that daily we are learning more about how what is happening in our gut, and the microbes that have colonised it, can affect our health. One of these metabolic health links that has emerged is glucose metabolism.

People with type 2 diabetes often show alterations in their gut microbiota composition, with a decrease in beneficial bacteria and an increase in potentially harmful ones. This dysbiosis as its called can contribute to inflammation, insulin resistance and impaired glucose regulation. All the classic hallmarks of type 2 diabetes. Probiotics aim to restore this balance.

Probiotics, which are defined as live microorganisms that confer a health benefit when taken in adequate amounts, have shown promise in modifying the gut microbiome. By introducing beneficial bacteria, probiotics may help restore balance to the gut ecosystem and potentially improve metabolic parameters such as glucose regulation. I won’t delve too much into just how they may do this as there are many pathways involved. But one such mechanism is through compounds produced by these bacteria when they metabolise prebiotics that are called short-chain fatty acids which influence insulin sensitivity, inflammation and even appetite. 

So how strong is the evidence for use of probiotics in managing the dysregulated blood sugars seen in type 2 diabetes? A recently published systematic review and meta-analysis set out to answer this question by examining the effects of probiotic supplementation on glycaemic control in adults with type 2 diabetes. The researchers scoured multiple databases to find relevant randomised controlled trials that could help to address the question.

All up, the analysis included 32 studies with a total of over 1,900 participants with type 2 diabetes. The probiotic interventions varied across studies, with different strains, dosages and durations of supplementation. In most of the trials though, the probiotics given were from the Lactobacillus or Bifidobacterium genera.

The primary outcomes of interest were changes in fasting blood glucose, HbA1c or glycosylated haemoglobin (which is a measure of long-term blood sugar control) and fasting insulin levels. And I’ll link to the study in the show notes. https://pubmed.ncbi.nlm.nih.gov/39349104

So, what did they find? The results were quite promising. Probiotic supplementation significantly reduced fasting blood glucose levels compared to placebo, with an average decrease of 0.7 mmol/L. There was also a significant reduction in HbA1c, with an average decrease of 0.44 percentage points. Fasting insulin levels showed a trend towards reduction, but this didn't reach statistical significance.

But there’s nuance in the results. For a start, dose and duration mattered with longer interventions greater than 12 weeks showing strong reductions in fasting glucose levels. And it seems that strains mattered with mixtures of Lactobacillus and Bifidobacterium performing best, but results varied.

It's important to note that while these results are encouraging, they should be interpreted with some caution. The quality of evidence varied across studies, and there was significant variation in the probiotic formulations used. This makes it challenging to pinpoint exactly which strains and dosages might be most effective.

So, should someone with type 2 diabetes try probiotics? The data is promising but not definitive. Here’s what to consider. Firstly, strain selection. Look for products containing Lactobacillus or Bifidobacterium species and which showed the most consistent benefits in the research. And patience pays as benefits emerged after 8–12 weeks, so consistency is key. And importantly, individual responses vary. Gut microbiome composition differs between people, so a probiotic that works for one person might not for another.

And the final and most important point is that probiotics are not a standalone fix, but instead should be a complementary strategy, not a replacement for diet, exercise or prescribed medications. Anyone with diabetes considering adding probiotics to their diabetes management plan should consult with their healthcare provider to ensure they're selecting an appropriate product and using it safely, especially if they are already taking medications designed to lower blood sugars.

So, let’s wrap all this. While probiotics show promise as a complementary approach to improving glycaemic control in type 2 diabetes, they're not a magic bullet. The foundation of diabetes management still rests on a healthy diet, regular physical activity and appropriate medication use. Because those first two factors of diet and exercise will also positively influence the gut microbiome on their own – it’s all related. Probiotics may offer an additional tool to support these efforts, but they should be viewed as part of a comprehensive approach to metabolic health, not a standalone solution.

So that’s it for today’s show. You can find the show notes either in the app you’re listening to this podcast on, or else head over to my webpage www.thinkingnutrition.com.au and click on the podcast section to find this episode to read the show notes.

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I’m Tim Crowe and you’ve been listening to Thinking Nutrition.