Did you know that your gut health can impact your blood glucose levels? The health and function of your gut, or gastrointestinal (GI) tract, greatly affects various aspects of overall metabolic health, including how your body regulates glucose.
To understand how this relationship works, it’s a good idea to take a closer look at what is going on in your gut.
Read on to learn how to boost your gut health and improve your blood glucose (or blood sugar) levels.
What is the Gut?
The first thing that comes to many people’s minds when they hear the phrase “the gut” is the intestines. However, the gut is made up of a system of several different organs, including:
- Small intestine
- Large intestine
- Pancreas (an accessory organ to the digestive system)
- Liver (an accessory organ to the digestive system)
- Gallbladder (an accessory organ to the digestive system)
Some people consider the human brain part of the gut from a functional perspective due to the intimate relationship between the gut and brain.
What Makes a Healthy Gut? Unpacking the Gut Microbiota
The answer to this question isn’t as straightforward as you may think. Based on the research, while there are some common markers of a healthy GI tract, there is no one-size-fits-all for what a healthy gut looks like.
The gut microbiota, or community of microorganisms that live in and on the human body, varies from person to person.
Think of it this way: each person’s gut is like a snowflake, and no two snowflakes are the same.
Gut Bacteria Can Be Good Bacteria
And what about gut bacteria? There are trillions of bacteria in the gut, along with archaea, fungi, viruses, and eukaryotes that have co-evolved alongside humans. Of these organisms, bacteria are the most abundant—there are 38 trillion!
Having fungi hanging around on your organs may sound strange, but rest assured that these organisms (when part of a balanced community in the gut) are beneficial to your health.
A healthy gut can help with everything from glucose control (to prevent and reverse prediabetes and manage chronic diseases like type 2 diabetes) and insulin resistance to maintaining healthy cholesterol levels and preventing cardiovascular disease.
So, What’s a Healthy Gut?
But what exactly is a healthy gut? As a general rule of thumb, a healthy gut has a diverse microbiota.
Some organisms may be more beneficial when they are abundant in the gut. These include Bifidobacterium and Lactobacillus.
When certain soluble fibers, such as inulin and fructooligosaccharides, are broken down and fermented, they encourage the growth of these beneficial bacteria (more tips to increase beneficial bacteria later on in the article).
These bacteria then produce chemicals called short-chain fatty acids, or SCFAs. SCFAs strengthen the gut barrier, reduce inflammation, and improve blood glucose and blood lipid levels.
However, these bacteria may worsen conditions such as small intestinal bacterial overgrowth or SIBO.
For others, they may improve SIBO. Again, it’s important to remember the no one-size-fits-all approach.
Microbiome or Microbiota?
It’s important to note that some people use “microbiota” and “microbiome” interchangeably. But there is a technical difference. The term “microbiota” refers to the microbes (or organisms), and “microbiome” refers to their genes.
And when most people refer to the microbiome, they mean the gut microbiome. However, we do have a microbiome on the skin and in our nose, mouth, and scalp.
Although this is a very new science (it was only discovered in the 90s), researchers have found that microbes in the gut have 3.3 million genes, which is 100 times the number of human genes!
This enormous microbiome is developed at birth. But some suggest we start the microbiome in the mother’s womb. The delivery method at birth, initial feedings, and early hygiene can all dynamically shape an infant's gut microbiome.
Dysbiosis: Where Gut Health Goes Wrong
Again, there is no one ideal or perfect microbiome, and each human is unique. However, a characteristic of an unhealthy gut is dysbiosis.
Dysbiosis is when the relationship between the number of different microbes is imbalanced in a way that may promote disease.
It may include an overgrowth of potentially harmful bacteria and fewer potentially beneficial bacteria. There is no definitive answer to what specific microbes are beneficial and which are not (remember the SIBO example?).
So, what is beneficial for one may not be for someone else. It may also have more to do with ratios of microbes rather than the absolute numbers.
Causes of dysbiosis may include:
- Poor diet
- Antibiotic use
- C-section delivery
- Possibly what and how you’re fed as a baby
- Non-caloric sweeteners
- Not getting enough activity as youths
- The hygiene hypothesis and over-sterilization of the environment
- Poor sleep
- Poor gut integrity or leaky gut
- Excessive alcohol intake
- Chronic stress
How the Microbiome Impacts Your Health
With the microbial genes far outnumbering human genes, it is no surprise that the human gut plays a vital role in overall health and wellness.
The microbiome breaks down complex carbohydrates, fats, and proteins. A breakdown of these nutrients creates metabolites (such as SCFAs). These can act both locally or systemically after being absorbed into the bloodstream.
The colon is the primary site where metabolites are produced. These metabolites can be beneficial or toxic, depending on the food you eat. For example, while soluble fiber increases beneficial metabolites such as SCFAs, some meat can create ammonia, which can be a harmful metabolite in excessive amounts.
Additionally, the presence of certain types of bacterial metabolites may be linked to diseases like colon cancer.
The microbiome can also synthesize specific vitamins such as vitamin K and B vitamins like biotin, cobalamin, folate, nicotinic acid, pantothenic acid, pyridoxine, riboflavin, and thiamine.
The Gut and Your Immune System
The gut also helps modulate the immune system. Inflammation is associated with high lipopolysaccharides or LPS.
LPS is an inflammatory toxin produced by gut microbes that can cause inflammation if it passes from the gut to the bloodstream.
It happens when the gut barrier is weak and becomes “leaky.” It’s important to understand enough about this because a leaky gut can play a role in diseases like Alzheimer’s and depression, and sometimes, even schizophrenia.
How the Gut Impacts Glucose Regulation: Tying It All Together
A leaky gut creates inflammation which reduces insulin sensitivity and is associated with metabolic disease.
By strengthening the gut barrier and reducing inflammation, SCFAs such as butyrate promote healthy blood sugar levels and support metabolic health.
Metabolic dysfunction has also been correlated with dysbiosis. A gut in dysbiosis will have fewer butyrate-producing microbes, which can reduce insulin sensitivity.
On the other hand, a healthy gut promotes the secretion of gut-derived metabolic hormones, including glucagons such as peptide-1 or GLP-1. This hormone increases insulin levels when there’s glucose in the blood, helping to get glucose into your cells to improve blood sugar levels. It also promotes feelings of fullness.
Improving Gut Health to Improve Glucose
Now that you’ve learned just how important the GI tract is in improving health and glucose levels, you may be eager to improve your gut health.
The first step is to take an individualized approach. There are general food choices and lifestyle habits to improve your gut health.
But there are some nuances. Remember that “beneficial” microbes are relative and what works for you may not work for another.
Lifestyle Choices for Good Gut Health
- Exercise can lead to a 50 percent reduction in intestinal blood flow, a stressor on the gut that can potentially lead to a leaky gut.
- The Nutrisense Nutrition Team recommended not eating two hours before and 45 minutes after to reduce GI symptoms.
Focusing on Your Diet
The dietary choices you make can also affect your gut, but there’s no one-size-fits-all for a healthy diet.
You may be avoiding a high-fat diet, considering intermittent fasting, practicing meal sequencing, or focusing on whole grains—it will all depend on your body’s individual needs.
It’s best to work with a dietitian to find out what works best for you. But here are a few general dietary choices to keep in mind that can help your gut thrive.
- As a general rule, you’ll want to focus on a variety of nutrient dense foods (in whole food form) and ensure you’re getting enough vitamins and minerals for you (again, working with a dietitian or nutritionist can help here) to prevent the body going into stress mode.
- You may also want to address additional dietary factors that can lead to physiological stress such as food sensitivities or intolerances (in most cases, your nutritionist or doctor may recommend avoiding such foods).
- To get into more of the specifics, research shows that a high-fiber diet improves insulin sensitivity in health and overweight men and women.
- The Nutrisense Nutrition Team also recommends limiting alcohol to three drinks (or even less for some people) since it’s known to affect the GI tract motility, absorption, and permeability.
- When it comes to prebiotics and probiotics, they may or may not be helpful for some. Some prebiotics or probiotics may be more helpful than others for you.
Additionally, some foods will be better for improving blood sugar levels than others. Sometimes, a specific food may be considered healthy but may not be optimal for your blood sugar levels.
Using a continuous glucose monitor (or CGM) alongside working with a registered dietitian or nutritionist will be very useful here.
You’ll be able to determine which foods are the best for your gut and optimize blood sugar levels even further using 24/7 glucose data.
There's so much more to learn about the gut and gut microbiome, from its interaction with weight loss and glycemic control to how it affects everything from the gastrointestinal tract to brain health. So stay tuned for more articles in this series to learn more about your gut!
Engage with Your Blood Glucose Levels with Nutrisense
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With Nutrisense, you’ll be able to track your blood glucose levels over time using a CGM, so you can make lifestyle choices that support healthy living.
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Heather is a Registered and Licensed Dietitian Nutritionist (RDN, LDN), subject matter expert, and technical writer, with a master's degree in nutrition science from Bastyr University. She has a specialty in neuroendocrinology and has been working in the field of nutrition—including nutrition research, education, medical writing, and clinical integrative and functional nutrition—for over 15 years.