BiotiQuest® Gut Health & Probiotics Blog with Martha Carlin

The Promising Relationship Between Probiotics And Blood Sugar

Martha Carlin | Mar 30, 2023 | 8 minutes read

Diabetes is a chronic disease marked by the body’s struggle to optimally use insulin and manage elevated blood sugar levels. According to the Centers for Disease Control and Prevention (CDC), in 2021, roughly 1 in 10 people in the United States had diabetes with over 90% suffering from type 2 diabetes.

Diabetes is a progressive disease that can lead to further health complications such as hypertension, stroke, heart disease, kidney failure, and retinopathy. 

Research in recent decades continues to shed light on the intrinsic connection between gut health and metabolic conditions such as diabetes and obesity. Keep reading to learn more about the various possible connections between the gut microbiome and blood sugar. 


The relationship between insulin, blood sugar, and diabetes

Insulin is one of the most important pieces of the diabetes puzzle. To understand the hows and whys of persistent high blood sugar, let’s quickly look into how insulin works to modulate blood sugar in a typical individual and the role insulin resistance might play in the development of prediabetes and type 2 diabetes.

What is insulin?

Insulin is a hormone produced in the pancreas that signals to glucose storage sites — cells, liver, and skeletal muscle — to absorb excess blood sugar for later use.  

Your body wants to maintain an optimum level of glucose in your blood at all times. As your cells absorb and use up existing blood sugar, your blood sugar level starts to drop. Your liver responds by releasing stored glycogen (a form of glucose) to continue to maintain blood sugar levels between meals.

In a typical person, the relationship between blood sugar and insulin works like a turnstile on a need-and-response basis. It goes like this:

  • After a meal, the blood sugar goes up, insulin gets released and excess glucose is stored for later use. 
  • As blood sugar goes down, the insulin in the blood drops. 
  • The lowered insulin in the blood triggers the liver to release stored glucose to maintain the optimum sugar level in the blood. 

The problem occurs when either the pancreas stops producing insulin altogether or glucose storage sites stop responding to the insulin. These phenomena are diagnosed as Type 1 and Type 2 diabetes.

What is HbA1c?

Hemoglobin (Hb) is a protein found in red blood cells that carries oxygen from the lungs to the cells of the body. Glycated hemoglobin (HbA1c) is a compound which forms when glucose in the blood attaches to the amino group present on the hemoglobin to form a ketoamine

An average red blood cell lives for up to 120 days and HbA1C levels can be used to predict average blood glucose level for the past 2- 3 months.

What is the difference between prediabetes, type 1, and type 2 diabetes?

Type 1 diabetes is an autoimmune disease where the body’s immune system attacks itself and damages the pancreatic B-cells that produce insulin. This lack of endogenous insulin leaves the body without one of the most important tools it uses to maintain energy.

Insulin triggers glucose storage in the cells and without insulin, glucose can continue to build up and circulate in the blood without being stored or used. 

Without access to glucose, the liver starts breaking down its fat reserves to produce ketones. Your body can use ketones for energy in the absence of glucose but high levels of ketones in the blood can lead to a life-threatening complication known as diabetic ketoacidosis (DKA). 

Apart from triggering glucose storage, insulin also suppresses lipolysis (breakdown of fat). In the absence of insulin, uncontrolled lipolysis might lead to an excessive production of ketone bodies in the liver. Excessive ketone production can lead to blood acidity which when left untreated might lead to coma and death.



How does type 2 diabetes differ from type 1 diabetes?

Type 2 diabetes isn’t due to the absence of insulin production but it’s due to insulin resistance. When you become insulin resistant, the cells stop responding to insulin to store glucose. 

Dr. Jason Fung, a well known researcher and physician in the treatment of diabetes and obesity, explains insulin resistance in type 2 diabetes as the body’s response to being oversaturated with glucose. 

With time as the blood sugar rises, your body produces more and more insulin, this can leave cells desensitized to insulin and over time they might stop responding to it altogether, as they are saturated per Dr. Fung’s research. Type 2 diabetes progresses over an extended period of time and it can be a result of years of silently building insulin resistance. 

Prediabetes is the stage when you’re beginning to have a higher blood sugar level than is typical, but it isn’t high enough yet to be diagnosed as type 2 diabetes. It can be a critical stage where intervention through diet and lifestyle choices can potentially put off the progression to type 2 diabetes.

According to Dr. Fung, reversing prediabetes and type 2 diabetes is entirely possible via lifestyle changes such as losing weight, eating whole foods and avoiding processed foods. 

He also recommends eating a low carbohydrate diet such as a ketogenic diet as well as by practicing intermittent fasting as a way to improve insulin sensitivity. You can learn more about Dr. Fung’s approach on how to manage type 2 diabetes and prediabetes here.

What is insulin resistance?

Insulin resistance occurs when the cells, muscles, and liver stop responding to insulin. In response to this resistance and to maintain the optimum blood sugar level, the pancreas has to release more and more insulin into the blood over time to lower blood sugar. 

Over months and years, the pancreas gets exhausted and cannot keep up with the body's demand for more insulin to manage its blood sugar level. At this point, the blood sugar starts to rise again and if left unchecked can lead to severe health complications. 


Gut microbiome and Dysbiosis

The age-old adage that you are what you eat makes its truth felt with every new connection that’s found between the gut and health. Gut dysbiosis, an imbalance between beneficial and pathogenic bacteria, is considered to be a central cause of several metabolic and cardiovascular health conditions. Whether you have good gut health (eubiosis) or bad gut health (dysbiosis), it can be traced back to diet, lifestyle, and genetics. 

Is gut bacteria linked to diabetes?

Your gut microbiome consists mainly of 6 types of bacterial phyla - Firmicutes, Bacteroidetes, Actinobacteria, Proteobacteria, Fusobacteria, and Verrucomicrobia. Of these six phyla, Firmicutes and Bacteroidetes make up about 90% of the microbial ecosystem. The ratio between these two dominant phyla may play a crucial role in maintaining gut eubiosis.

Several studies have pointed out that there’s a difference in the gut microbiome of diabetic patients as they host a higher bacteroidetes to firmicutes ratio in their gut. 

In prediabetic patients, it’s possible that the difference in the gut microbiome may already be seen when compared to non-diabetic subjects. Patients with type 2 diabetes may have fewer butyrate (SCFA) producing bacteria when compared to non-diabetic patients. Butyrate has been associated with glucose homeostasis and increased insulin sensitivity. 

Can you influence your gut diversity with diet and probiotic supplements?

Fiber intake has been highlighted as a source of microbial stability and higher microbial diversity. Fermentation of fiber by beneficial bacteria such as F. prausnitzii and B. bifidum in the gut produces SCFAs such as butyrate. High fiber and butyrate-rich foods such as greens and butter can have a positive effect on gut diversity and glucose metabolism. 

Probiotic supplements are increasingly being considered to potentially strengthen gut barrier integrity, enhance butyrate production, increase gut microbial diversity, and reduce proinflammatory markers.

The connection between the gut microbiome, insulin sensitivity, and glucose homeostasis is being explored as a potential support in diabetes symptoms management. Clinical studies suggest a possible positive association with the prevention and management of diabetes by modulating the gut microbiome.


Research connecting blood sugar and probiotics

Let’s take a look at recent studies that explore the effect probiotics might have on enhancing insulin sensitivity and improving SCFA production in the gut.

Do probiotics affect serum HbA1c?

A meta-analysis of 32 randomized clinical trials conducted by Kocsis, T. et al. (2020) published in Nature studied the effect of probiotic supplements on cardiovascular and metabolic health markers such as BMI, total cholesterol levels, LDL, triglycerides, HDL, CRP (C-reactive protein, an inflammatory marker), HbA1c levels, fasting glucose, fasting insulin levels, systolic and diastolic blood pressure in type 2 diabetes. 

The analysis suggests a significant positive correlation between probiotic supplementation and a reduction in total cholesterol, triglyceride levels, CRP, HbA1c, fasting plasma glucose, fasting insulin levels, and both systolic and diastolic blood pressure, and an increase in HDL (good cholesterol). 

Which are the best probiotics for blood sugar?

Studies on the effect of probiotics on blood sugar have leaned towards exploring the effects of lactobacillus and bifidobacterium strains, such as Lactobacillus acidophilus, Lactobacillus casei, and Bifidobacterium bifidum.

Do probiotic supplements lower blood sugar?

According to this systematic review and meta-analysis, the subset of trials conducted independently from food industry funding found a significant change in serum HbA1c in favor of probiotics containing bifidobacterium strains. Other strains used in trials included lactobacillus strains and streptococcus. 

Naito et al. found a positive relationship between Lactobacillus casei strain Shirota (LcS) supplementation in obese mice and improved insulin resistance and a decrease in LPS, a bacterial toxin that triggers inflammation when in the bloodstream.

According to results published in Scientific Reports of a randomized, double-blinded, placebo-controlled trial with 68 type-2 diabetes patients conducted over a period of 9 months with L. reuteri strains ADR-1 and ADR-3, the group that was given the live strain of L. reuteri ADR- 1 displayed a significant reduction of blood serum HbA1C.


Ways probiotics might play a role in lowering blood sugar levels

Researchers have explored various mechanisms that might explain the positive association of probiotics with improved glucose homeostasis and insulin sensitivity symptoms. The gut flora produces metabolites such as short chain fatty acids (SCFAs) and secondary bile acids (SBAs) that can either lead to homeostasis or inflammation. Let's look at how some of these metabolites might affect serum HBA1c and insulin sensitivity.

LPS and Inflammation

Research shows that people with diabetes have higher concentrations of Lipopolysaccharide (LPS) in the blood. LPS is a bacterial toxin produced in the gut and it can pass through a weakened gut barrier into the bloodstream. The presence of LPS in the bloodstream evokes a proinflammatory response by your immune system which has been associated with several metabolic disorders including type 2 diabetes. LPS-induced inflammation has been associated with increased insulin resistance.

A healthy and diverse gut microbiome has been credited with maintaining gut barrier integrity, which doesn’t allow for bacterial toxins to pass through the gut barrier. 

BSH activity of probiotics supports GLP-1 release

Primary bile acids (BAs) produced in the liver are released into the intestine after a meal. BAs facilitate the absorption of lipids and fat-soluble vitamins in the intestine. Probiotics break down and convert primary bile acids into secondary bile acids (SBAs) through Bile Salt Hydrolases (BSH) activity. BSH is produced by various strains of lactobacillus and bifidobacterium. 

The conversion of primary BAs into SBAs plays a vital role in regulating bile acid synthesis, and cholesterol homeostasis in the body. BAs and SBAs trigger the release of GLP-1 (glucagon-like peptide-1) which is responsible for insulin secretion and lowering blood sugar.


What are the potential side effects of probiotics?

Different people react to different foods and supplements differently. It's best to consider some of the possible side effects of probiotics before adding a dietary supplement or any other probiotic food to your diet.

  • Patients with immunodeficiency or immunocompromised disorders might be at risk of developing complications due to probiotics use.
  • There’s a potential risk of antibiotic resistance transfer from probiotics to pathogens, if the organisms have not been properly screened and selected.
  • Sensitive individuals might undergo an allergic response. 

Probiotics and Blood Sugar

Our gut microbiome interacts with the body in countless ways through the production of by-products such as SCFAs or SBAs that then trigger and enhance essential processes like insulin sensitivity, glucose homeostasis, and lipid metabolism. 

Biotiquest’s probiotic supplements such as the Sugar shift are enriched with strains such as Bifidobacterium longum, Bifidobacterium bifidum, Lactobacillus plantarum, Lactobacillus casei, Lactobacillus reuteri, and more, and might just be the perfect ally you need in reaching your health goals. 

With gratitude,

Martha Carlin photo Martha Carlin, is a “Citizen Scientist”, systems thinker, wife of Parkinson’s warrior, John Carlin, and founder of The BioCollective , a microbiome company expanding the reach of science and BiotiQuest, the first of it’s kind probiotic line. Since John’s diagnosis in 2002, Martha began learning the science of agriculture, nutrition, environment, infectious disease, Parkinson’s pathology and much more. In 2014, when the first research was published showing a connection between the gut bacteria and the two phenotypes of Parkinson’s, Martha quit her former career as a business turnaround expert and founded The BioCollective to accelerate the discovery of the impact of gut health on all human disease. Martha was a speaker at the White House 2016 Microbiome Initiative launch, challenging the scientific community to “think in a broader context”. Her systems thinking background and experience has led to collaborations across the scientific spectrum from neuroscience to engineering to infectious disease. She is a respected out of the box problem solver in the microbiome field and brings a unique perspective to helping others understand the connections from the soil to the food to our guts and our brains.

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