Gut Health and Blood Sugar Regulation

Written by Kathryn Davis, MS, Nutrition Specialist

The Gut-Brain-Liver Axis

If you've been around here long enough, you will hear me say (almost daily) "gut health is absolutely foundational"! It is a key pillar to all aspects of health. Today we're exploring the connection between your gut health and your blood sugar control. This two-way connection is often referred to as the gut-brain-liver axis, meaning that these systems directly interact with each other. What goes on in your gut affects your blood sugar and vice versa. Blood sugar regulation is not just about managing carbohydrate intake, the gut microbiome also strongly influences how your body processes food and responds to insulin.

Now let's back up a moment and ensure you are in the know about the gut microbiome. Inside of your digestive tract, mainly the large intestine, is a gigantic community of bacteria and other microorganisms. It's often stated that the number of bacteria organisms in your body out number your human cells - so these critters influence numerous systems. The microbial diversity of this community is what makes all the difference. Some bacteria are considered opportunistic and can harm your health when overgrown. They often crowd out the good bacteria and can increase overall inflammation. Certain bacteria like Akkermansia muciniphila and butyrate-producing species such as Faecalibacterium prausnitzii and Roseburia intestinalis are associated with better gut-barrier function, lower inflammation, and healthier glucose metabolism. However, it's important to keep in mind that probiotic effects are strain-specific, and current evidence does not support treating any single bacterium as a universal solution for insulin resistance. This is where fermented whole foods makes a huge difference!

How the Microbiome Affects Metabolism

Bacteria feed on undigested fiber. Humans lack the enzyme to break down the β-1,4 glycosidic bonds connecting glucose molecules in cellulose, a type of insoluble fiber. Your digestive enzymes can break the α-1,4 bonds in starch, but we do not produce cellulase, the enzyme needed to split cellulose’s β-1,4 bonds. Therefore, cellulose passes through the small intestine mostly undigested and feeds the bacteria in your gut microbiome. When bacteria digest these fiber, it ferments the fiber and releases short chain fatty acids (SCFA). These SCFAs include butyrate, propionate, and acetate and these 3 fatty acids are responsible for maintaining and repairing the mucosal lining in your intestine. An imbalanced microbiome, also known as dysbiosis, can interfere with these processes and largely contribute to metabolic dysfunction.

In short, short-chain fatty acids may support:

• Insulin sensitivity

• Intestinal barrier integrity

• Appetite and satiety signaling

• Glucose and fat metabolism

• Regulation of inflammation

GI Dysfunction and Insulin Resistance

Dysbiosis can cause damage to the intestinal barrier and allow bacterial components and large undigested food particles to enter the blood stream. Your immune system sees these particles as a threat and can trigger low-grade systemic inflammation, which may disrupt insulin signaling.

When cells become less responsive to insulin, the pancreas must produce more insulin to manage blood glucose. Over time, this can contribute to elevated blood sugar, increased fat storage, and a greater risk of metabolic syndrome and type 2 diabetes.

There are many GI concerns that can show up when dysbiosis is present:

• Constipation or diarrhea

• Frequent bloating

• Abdominal discomfort

• Irregular bowel movements

• Food intolerances

It's worth investigating your gut health and bacterial diversity if you experience these symptoms daily!

Fiber Fueled

One of my favorite gut health books is Fiber Fueled by Will Bulsiewicz MD. He dives deep into fiber's role in gut health and the microbiome, but I will summarize the important takeaways here.

In addition to feeding bacteria and supporting SCFA production, fiber plays an important role in blood sugar regulation by slowing down digestion and glucose absorption. When we consume soluble fiber it combines with water and forms a gel-like substance. This substance coats the inside of our intestines and helps slow the release of glucose into the blood stream. In turn, this reduces rapid post-meal blood sugar spikes.

There are so many lovely high-fiber foods. The best ones include:

• Non-starchy vegetables**

• Berries, apples, and pears

• Beans and lentils

• Nuts and seeds **

• Oats and barley

• Onions, garlic, asparagus, and artichokes (especially Jerusalem artichokes) **

**best for those with insulin resistance or blood sugar dysregulation

Tracking fiber intake is one of the best ways to support gut health and help you keep you aware of your net carb intake. As Dr. Will Bulsiewicz says in Fiber Fueled, go LOW and SLOW when introducing fiber. This is especially important if you are new to a fiber-rich diet. I often recommend tracking your current intake and then slowing increasing by 2-5g every few days until you reach 30-40g daily. It's also key to stay extra hydrated to reduce potential gas, bloating, or constipation.

Probiotics and Fermented Foods

The last top food for supporting gut and metabolic health are fermented foods. Fermented foods contain live microorganisms that support a diverse microbiome. These often contain a wide variety of live cultures and can sometimes be more beneficial than targeted supplementation to the diversity. Oftentimes people respond better to incorporating fermented foods into their diet than taking a probiotic supplement.

Some of my favorite fermented foods include:

• unsweetened yogurt from grass fed cows or organic nut milks

• kefir (water or milk based)

• kimchi

• sauerkraut

• naturally fermented pickles (Bubbies pickles are to die for)

• miso

• tempeh

• kefir

• raw cheese that contains live and active cultures

Practical Gut-Supportive Meal Ideas

Use a simple formula when building your meals to take the complexity out of your meal decisions.

An easy and effective principle to use: protein + fiber-rich plants + healthy fat + optional resistant starch.

Using this principle ensures you are supporting satiety, blood sugar control, and gut health.

Here are a few examples:

• Plain Greek yogurt or dairy-free yogurt with berries, chia seeds, walnuts, and cinnamon

• Vegetable omelet with avocado and a side of berries

• Salmon bowl with roasted vegetables, avocado, and cooked-and-cooled quinoa

• Chicken or tofu stir-fry with broccoli, cabbage, mushrooms, and a small portion of cooled-and-reheated brown rice

• Turkey or tempeh lettuce wraps with crunchy vegetables and fermented vegetables

• Bean and vegetable salad with olive oil, herbs, pumpkin seeds, and grilled protein

• Chia pudding with unsweetened milk, berries, and nut or seed butter

If digestive symptoms or blood sugar fluctuations are making it difficult to know what to eat, personalized nutrition guidance can help identify a strategy that supports both your gut and metabolic health. Consider partnering with us so we can deep-dive into your individual needs!