Everything You Need To Know About Your Serotonin + Gut Health Connection

by | Sep 21, 2022 | Dr Will Cole, Wellness


Moving into the fall and winter season means cozy sweaters and pumpkin everything. But with the seasonal shift, our immune systems are working overtime to fight back against the bugs that crop up as we spend more time indoors and the temp drops.

Keeping our immune system strong takes more than popping a few doses of vitamin C. If we dig a little deeper, we can see that a responsive immune system is dependent on our microbiome health. In some ways, this shouldn’t come as a big surprise, right? We know that our gut bacteria are instrumental in so many aspects of our health. But their role in our immune system may top the list.

The microbiome is like a rainforest. We need to feed it with plant-based carbohydrates for our bacteria to thrive. Plus, plants are full of fiber, antioxidants, polyphenols, minerals, and vitamins that our immune systems depend on to function at their best. The more plants you eat every day, the more resilient and powerful your immune system will be.

It Starts with Fiber

You probably know that fiber is good for you. And you also probably know that veggies are a good source. But what exactly is fiber? Fiber is the part of plants we can’t digest. It’s found in fruits, vegetables, and whole grains. It’s a carbohydrate, but it doesn’t raise blood sugar as quickly as other carbs for most people.

There are two types of fiber: soluble and insoluble. Soluble fiber dissolves in water, forming a gel-like material that slows digestion and the absorption of sugar into your bloodstream. For soluble fiber, think oat bran, nuts, seeds, apples, citrus and beans.

The other type, insoluble fiber, doesn’t dissolve in water. It adds bulk to stools, making them softer and easier to pass through your gut. It basically acts like a scrubbing brush that cleans things out as it moves through your body. Insoluble fiber includes fruit and veggies (we love raw, unpeeled carrots for their healthy dose of hormone-balancing insoluble fibers!), whole grains like brown rice or barley, wheat bran, and nuts to name a few.

high fiber

Why is Fiber so Good for You?

The list of reasons why fiber is just so amazingly powerful at keeping us well is long. It helps with blood sugar control by slowing down digestion so that glucose enters your bloodstream gradually instead of all at once after a meal. This reduces peaks and valleys in our energy levels throughout the day and gives us more stable moods and fewer cravings for sugary snacks.

Whole foods should be your first choice. Wholefoods are food in their entire or very minimally processed form. Examples include strawberries, beans, eggs, and extra virgin olive oil. Each whole food contains various nutrients: vitamins, minerals, phytonutrients (plant nutrients), fatty acids, amino acids, and more. We can only isolate what we understand; there is likely so much to learn about each food and how nutrients work in synergy.

Food is information. Food relays information to our body about our environment and interacts with our genes. Nutrigenomics is the study of this interaction. Beyond calories, food influences inflammation, hormone balance, fertility, perimenopausal symptoms, and everything else.

Nutrition is very personal. We are each unique in our nutrition needs. What foods our body needs for optimal health will differ from pregnancy to lactation to menopause. In addition, nutrition approaches that feel best for your body will likely change over time. Part of using food as medicine is tuning in and adapting.

My Principles of Using Food as Medicine

Your gut microbiome is your intestinal flora. It’s made up of trillions of bacteria, fungi, and viruses that live in your digestive tract. The microbiome helps us fight back against infections, digest our food, balance hormones, and synthesize vitamins. It also helps balance our mood, stress response and basically contributes to all areas of our health.

Why does fiber matter for your microbiome? Because your gut bacteria feed on all that fiber that you can’t digest. And more fiber is associated with a critical piece of gut health: diversity. While we still have so much more to learn about the microbiome, we do know that diversity, or how many different types of bacteria you have in your gut, is a requirement for a healthy gut.

So diversity is vital on both sides. Plant diversity or eating many different types of fiber-rich carbohydrates boost your microbiome diversity.

How Does Your Microbiome Impact Immunity?

The microbiome regulates our immune system. And how well it does this is closely tied to the diversity of plant foods in our diet.

But how does that work? How do bacteria help us fight off viruses or infections?

To start, nearly 80% of your body’s immune cells reside in your gut, impacting your immune system in several ways.

First, your gut lining acts as a defensive barrier that keeps things like pathogens or large proteins from entering your bloodstream that could otherwise trigger an inflammatory response. And here’s where it gets super interesting – within the mucosa of your gut, live immune-supporting tissues, cells, and proteins like gut-associated lymphoid tissue, aka GALT, specialized mucosal immune cells, antimicrobial peptides, secretory IgA, and more.

All of these are critical pieces of your immune system that help your body recognize and fight back against threats to your health. So the mucosal lining helps balance your immune response, keeping not just your gut healthy but your entire body.

But dysbiosis or an imbalance of healthy gut bacteria can alter the health of the entire gut, including the gut lining. That’s why it’s critical to support your microbiome with plant fiber. And the impact of plant diversity isn’t just about the bacteria itself. It’s about what those bacteria do when they ferment fiber-rich carbs and make short-chain fatty acids (SCFAs).

We’ll dive into just how SCFAs keep you healthy and tips to make it easier for you to meet your daily fiber needs in part two (hint: our Paleo and Ketotarian do all the work for you).

And in the meantime please reach out with any questions or concerns, we love hearing from you. Stay tuned!

Tricia Williams

Tricia Williams

Tricia Williams is a talented Chef recognized as a leader in the fields of Nutrition and Holistic Health. Some years ago, Tricia founded Food Matters, a boutique, nutritionally-sound meal delivery service. Closely collaborating with her clients’ coaches, integrative physicians, and nutritionists, Tricia was able to successfully tailor meal plans that met both their taste preferences and their health goals.

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