Obesity, Type 2 Diabetes and the Gut Flora – Is it all about Butyrate?

type 2 diabetes and the gut microbiome how to loose weight

Is obesity and type 2 diabetes being driven by bacterial infections or overgrowths in the large bowel? There seems to be an emerging pattern here. It all comes back to the gut. Today we will be exploring the connections between type 2 diabetes, metabolic syndrome and obesity and the thousand plus species of bacteria that inhabit our gut. 

Drivers of obesity leading to type 2 diabetes

Excessive weight gain, Type 2 diabetes and metabolic syndrome have been labelled a lifestyle disease. We are all at least familiar with the common causes. 

  • Poor food choices 
  • Sedentary lifestyle 
  • All leading to obesity, poor blood sugar control and eventually type 2 diabetes. 

This results in insulin resistance – the sugar being transported in the blood cannot be taken up by the cells throughout the body, and beta-cell dysfunction – the beta cells, found in the pancreas produce insulin needed to move sugar from the bloodstream into the cells. Here we see the classic ‘overfed and undernourished picture (1)’.

These common drivers resulting in insulin resistance paint the picture of poor blood sugar control. Chronically elevated blood sugar can trigger a whole range of chronic health conditions such as neuropathy, cardiovascular diseases and poor wound healing. 

Common symptoms include

  • Frequently needing to urinate
  • Exhaustion 
  • Excessive thirst
  • Excessive hunger
  • Feeling faint or dizzy
  • Poor wound healing
  • Numbness in the hands and/or feet

We know that blood sugar control is the number one factor in the development of metabolic syndrome and type 2 diabetes, but what is happening in the gut?

Gut Bugs, obesity and Type 2 Diabetes 

I will be the first to admit that I have a bias. 

My bias is that many diseases either start in the gut (from some form of imbalance, infection or overgrowth) or that gut imbalance can be a strong driver of the disease. 

There have been countless studies trying to define what a healthy human microbiome actually looks like. For many years the balance between two of the dominant phyla in the human gut was proposed. Here we saw studies suggesting that a microbiome that had more Firmicutes and fewer Bacteroidetes would drive obesity. Members of the Firmicutes phylum appear to be better at harvesting energy from the food we eat. Therefore, the more Firmicultes bugs the better you turn the food you have eaten into energy. This leads to an overabundance of energy which is stored as fat (2, 3).

It is a good theory and may be accurate but what is emerging from more recent studies into the gut microbiome tells a different story. The real answers around what type of gut flora drives obesity, type 2 diabetes and metabolic syndrome may lie just a tad deeper than looking at the picture from the phylum level (probably about as broad as we can look at it!). 

Newer studies have come to the tentative conclusion that the Firmicutes:Bacteroidetes ratio may not be the real driving factor of obesity but a lack of diversity. Diversity within our gut microbiome appears to be one of the most important factors for health and wellbeing (4).

That line of thinking is just a tad scary when you consider how frequent antibiotics are prescribed and how common cesarean sections are becoming. Both of these practices and more lead to ever dwindling gut flora. As our gut microbiome is passed from mother to child this quickly turns into a generational problem.

Getting into the specifics we can see a pattern of dysbiosis in type 2 diabetes. 

Dysbiosis.
A term for a microbial imbalance or maladaptation on or inside the body, such as an impaired microbiota. 

As diabetes progresses the microbiota changes (5, 6).

  • Beneficial butyrate producing bacteria decrease such as Akkermansia muciniphila and Faecalibacterium prausnitzii
  • Opportunistic bugs increase such as Bacteroides caccae, Clostridium hathewayi, Clostridium ramosum, Clostridium symbiosum, Eggerthella lenta and Escherichia coli
  • Sulphate-reducing bacteria such as Desulfovibrio increased – As a byproduct this particular bug produces a toxic gas called hydrogen sulfide. This gas is associated with inflammatory bowel disease and can shut down the production of butyrate (a helpful short chain fatty acid that we will discuss later in this article). These bugs also play a role in certain SIBO cases too (7).

So what is the connection between poor insulin sensitivity and the altered gut microbiome seen in type 2 diabetes? As I mentioned above, insulin is needed by cells to uptake sugar in the blood. The connection between poor insulin sensitivity and our gut flora may come down to the lack of beneficial bacteria that produce incredibly helpful short chain fatty acids, most importantly butyrate. 

Butyrate – The All star Short Chain Fatty Acid 

Right now, at this very moment, the residents of your large bowel are engaged in countless different processes. One of them is the fermentation and conversion of fibre and starches into short chain fatty acids. This topic gets complicated. I’m sure it needs its own article to give it the attention it deserves. For now let’s focus on the generation of one particular short chain fatty acid and all the amazing things it does in relation to    

Butyrate can do a whole bunch of great things for people that are struggling with weight gain, type 2 diabetes or metabolic syndrome (8, 9)

  • Increase satiety meaning you will be less hungry with less food
  • Enhance energy expenditure by boosting mitochondrial function, thermogenesis and fat break down and usage
  • Improve beta-cell function – the cells in the pancreas that produce that much needed insulin (often beta cells become dysfunction in type 2 diabetes)
  • Reduce inflammation by improving gut barrier function 

Here we are only scratching the surface of all the amazing things that butyrate, produced in the large bowel, can do. We are still in the early days of working out how it has all these amazing effects on the body. 

A review paper published in 2019 helps to outline how these short chain fatty acids do what they do. 

Image taken from: Gut microbial metabolites in obesity, NAFLD and T2DM.

Let’s review those points here. 

Decreasing hunger

Butyrate can decrease hunger and regulate your energy intake by stimulating a number of interesting peptide hormones including peptide YY and glucagon-peptide 1. These hormones, generated in the gut, regulate how hungry we are. One study, cited in the review, found that increasing the release of these peptides reduces food intake by 14% in obese patients. It gets more complicated from there. The vagus nerve and the inhibitory neurotransmitter gamma-aminobutyric acid (or GABA) may be involved as well. 

Increasing Energy Expenditure

Short chain fatty acids, including butyrate, may also increase the amount of energy that you use, thus reducing weight. This is mainly seen in animal studies where lipid peroxidation and increased thermogenic capacity was seen in mice who were administered butyrate. A number of different genes were upregulated and resulted in weight loss. There have been some studies in humans that show promise but we are still trying to work out the details. Remember animal studies don’t always translate well to humans.

Butyrate and Liver Disease

The gut has a strong influence on the health and vitality of the liver. This connection is clear as day when you look at the anatomical connection between the two via the portal vein. 

Read more about how gut infections can impact your liver and lead to non-alcoholic fatty liver disease – Gut Infections – The Gut Liver Connection


Recommended reading

Learn more about how gut infections can impact your liver and lead to non-alcoholic fatty liver disease


Again we can see butyrate improving our health by improving the health of our liver. Butyrate can improve leaky gut by improving the tight junctions that keep our gut wall working smoothly (keeping the wrong things out and letting the right things in). The knock on effect here is the prevention of toxic metabolites from certain less-than-friendly gut bugs from making it through the gut wall and on towards the liver. These toxic byproducts from gram-negative bacteria are known as lipopolysaccharide (LPS) also known as endotoxins.   

Image taken from: Microbial Modulation of Insulin Sensitivity

Insteading of Guessing let’s Test

How do we assess bacterial imbalances? Each week I receive emails from people with gut test results looking for answers. It is a familiar email. I have been in the same position. Looking for answers and trying my damndest to get to the bottom of my poor gut health. In many of my reply emails I have to help the sender understand the difference between a stool test looking for specific gut infections and a stool test assessing the whole bacterial ecosystem. 

Let me take a few short paragraphs to outline the key points here.

First off the test assessing the gut for specific infections (parasites, fungal overgrowths, key bacterial infections). The best test on the market at the moment for this (in my humble opinion) is the GI-MAP stool test, which you can learn more about here. 

This test uses DNA based technology to screen for top gut infections. It will also give you key markers around inflammation in the gut, digestive function and even gluten sensitivity markers too! Pretty darn impressive. While the GI-MAP does give you a brief snapshot of what the whole microbial ecosystem is doing, it doesn’t actually spell it out for you. An experienced gut savvy clinician can help to fill in the blanks and make educated guesses on the bacterial balances and whole ecosystem composition, but they are still simply guessing. 

Onto the second type of stool test looking at the ecosystem as a whole. The best one on the market (again in my humble opinion) is the Ubiome explorer. This test is DNA based (imperative!) and will give you the 10,000 foot view of the bacterial makeup of your large bowel. Why is this different from the test above? Well for starters it doesn’t screen for fungal, viral or parasitic infections. Sounds like you could be missing some vital information here right? What you are trading off for here is a very valuable insight into the whole bacterial gut makeup. Something that I have come to look at as an ecosystem wide assessment of the gut. Insights from this test have incredible and astounding implications on health and disease. Something we are exploring today in relation to type 2 diabetes.

The third type of stool test is the old-fashioned culture and microscopy. Some health professionals still rely on these tests to find and treat gut infections. They are very much a thing of the past. They rely on a lab technician looking into a microscope to identify something tiny and easy to miss. A lecturer who spent years as a lab tech described this as looking for one specific needle in a pile of needles. Needless to say, a hard job.

How to choose the right stool test? 

Here we need to take a thorough case history and work backwards towards the best test for you. There isn’t a right or wrong answer here, only the best test to get to the bottom of your health issues.

Ok, now back to the subject at hand. Type 2 diabetes and the gut. 

Beneficial Bugs versus Bacterial overgrowths

Again and again we can see bacterial overgrowths and imbalances in the gut as a result from poor dietary and lifestyle choices. Here we have outlined that the shift in the gut microbiome could actually be a driver of obesity, type 2 diabetes and metabolic syndrome. 

“Manipulation of gut microbiota through the administration of prebiotics or probiotics could reduce intestinal low grade inflammation and improve gut barrier integrity, thus ameliorating metabolic balance and promoting weight loss.”

Gut microbiota and metabolic syndrome

That pretty much sums it all up. We can reference all the new fancy research there it is but it all comes back to healthy diet and lifestyle choices. Choosing fiber rich foods that feed our beneficial gut bugs can help to shift the gut back towards a healthier balance. The knock on effect of indigestible carbohydrates being fermented by butyrate producing bugs can help with satiety, increase energy expenditure and even decrease the toxic load on your liver! 

Now over to you. Have you experimented with adding prebiotics into your diet? What were the results? Share your thoughts in the comments below. 

References and Resources 

  1. The relative contributions of insulin resistance and beta-cell dysfunction to the pathophysiology of Type 2 diabetes
  2. Use of pyrosequencing and DNA barcodes to monitor variations in Firmicutes and Bacteroidetescommunities in the gut microbiota of obese humans
  3. Association between body mass index and Firmicutes/Bacteroidetes ratio in an adult Ukrainian population
  4. Understanding the Role of the Gut Microbiome and Microbial Metabolites in Obesity and Obesity-Associated Metabolic Disorders: Current Evidence and Perspectives 
  5. A metagenome-wide association study of gut microbiota in type 2 diabetes 
  6. Understanding the Role of the Gut Microbiome and Microbial Metabolites in Obesity and Obesity-Associated Metabolic Disorders: Current Evidence and Perspectives 
  7. Toxicity of hydrogen sulfide toward sulfate-reducing bacteria Desulfovibrio piger Vib-7
  8. Understanding the Role of the Gut Microbiome and Microbial Metabolites in Obesity and Obesity-Associated Metabolic Disorders: Current Evidence and Perspectives 
  9. Enhanced translocation of bacteria across metabolically stressed epithelia is reduced by butyrate.
  10. Gut microbial metabolites in obesity, NAFLD and T2DM
  11. Gut microbiota and metabolic syndrome

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