The Gut–Thyroid Connection: What You May Be Missing About Hypothyroidism
🕒 7-8 min read
Pressed for time? Here’s the short and sweet scoop:
Supporting your gut health can unlock better thyroid function, boosting your energy, mood, digestion, and overall balance.
Start by including protein, healthy fats, and fiber at every meal to help balance blood sugar and reduce thyroid stress.
Ready to deepen your journey? Explore my blog posts linked throughout to nourish your thyroid and gut naturally.
This blog is for you if you’re tired of unexplained fatigue, brain fog, or digestive issues and want a practical path to support your thyroid beyond medication.
📌 Keep reading - or save this post to learn how healing your gut can help restore your thyroid balance.
You might have heard about hypothyroidism before, or even been diagnosed, but understanding what it really means for your body can feel confusing.
Maybe you’ve been making healthy changes like eating well, moving more, cutting sugar, but still feel stuck with fatigue, brain fog, or weight that won’t budge. Maybe you’ve focused mostly on medication alone. But supporting your thyroid often means looking deeper.
I see this often as a holistic nutritionist, and it’s an important conversation because your thyroid health is connected to many parts of your body: your gut, immune system, and even your brain.
Over my 12+ years working as a nutritionist and gut health expert, I’ve found that educating my clients about the interconnectedness of the body is essential. I’ve also seen how a holistic approach can support thyroid function and help you feel more like yourself.
Let’s explore what hypothyroidism really is, how it’s linked to your gut health, and what steps you can take to support your body’s balance.
What Is Hypothyroidism?
Your thyroid is a small, butterfly-shaped gland that sits at the base of your neck. But don’t let its size fool you, this little gland plays a big role in how you feel every day. It helps regulate your metabolism, energy levels, body temperature, mood, digestion… the list goes on.
When your thyroid is functioning properly, it releases TSH (thyroid stimulating hormone), which in turn helps produce two key hormones: T4 (inactive) and T3 (active).
Your thyroid produces about 90% T4 and only 10% T3. That means your body relies heavily on its ability to convert T4 into T3, the form that actually tells your cells to produce energy and function well.
What many people don’t realize is that most of that conversion doesn’t happen in your thyroid. It happens in your gut, liver, brain, muscles, and kidneys. So if any of those systems are out of balance, your thyroid can’t do its job, even if your lab results look “normal.”
This is why you can still feel tired, foggy, and stuck…even when your thyroid is technically producing hormones.
Now if your thyroid isn’t making enough hormones, or if your body isn’t converting them properly, you’re dealing with hypothyroidism, also known as an underactive thyroid.
And often, the root of the issue isn’t just the thyroid itself. It’s that your body isn’t able to activate or use those hormones properly.
But once you start looking at your thyroid through a more holistic lens…that’s where the deeper healing begins.
Looking at your thyroid through a more holistic lens opens the door to deeper healing, bringing clarity to the connections beyond just the gland itself.
What Causes Hypothyroidism? (It’s More Than Just Your Thyroid)
There are many reasons why your thyroid might be underperforming and most of them involve systems outside your thyroid itself.
Because the root cause can be different for everyone, it’s important to look at the whole picture. Here are seven of the most common factors that may be contributing to thyroid dysfunction:
Blood Sugar Imbalance
When your blood sugar swings too high or too low, from insulin resistance or a diet high in sugar and refined carbs, it puts stress on your hormonal signaling. That includes your thyroid. These imbalances can suppress your body’s ability to convert T4 into active T3, the hormone that helps regulate how your cells use energy.Chronic Stress
Ongoing stress increases cortisol, which can lower TSH and reduce your ability to convert T4 into T3. So even if your thyroid is technically doing its job, chronic stress can make it harder for your body to use those hormones properly leaving you with all the symptoms of hypothyroidism.Gut Dysfunction
Your gut doesn’t just digest food, it also converts roughly 20% of your T4 into active T3. It’s also where key nutrients like selenium, zinc, magnesium, and iodine get absorbed. If you're dealing with digestive issues like leaky gut or microbiota dysbiosis, it can interfere with how well your thyroid functions.Liver Overload
Your liver is another major site for thyroid hormone conversion. But if it’s overburdened by toxins, inflammation, or a poor diet, that conversion process can slow down. So even if your thyroid is making hormones, your body may not be activating them efficiently.Micronutrient Deficiencies
Low levels of selenium, zinc, magnesium, or vitamin D can make it harder for your body to produce, convert, and use thyroid hormones. These nutrients also help regulate inflammation and support immune function, two key players in thyroid health.Hidden Inflammation or Autoimmunity
Chronic inflammation from processed foods, food sensitivities, infections, or long-standing gut issues can disrupt thyroid function over time. It also raises your risk for autoimmune thyroid conditions like Hashimoto’s, one of the most common causes of hypothyroidism.Misleading Lab Results
Most doctors test only TSH to assess your thyroid health. While TSH is an important marker, it reflects how much active thyroid hormone (T3) is reaching your pituitary, not the rest of your body. That means your TSH can look “normal,” even while your other cells are still running on empty.
Many factors can contribute to hypothyroidism. Taking time to reflect and explore possibilities like stress, gut health, and nutrient imbalances is a powerful first step toward clarity and relief.
How to Support Your Thyroid and Gut Naturally
These are the steps I come back to again and again with clients because they truly help. Backed by science and guided by real-life experience, each one is designed to support your body in a way that feels nourishing, not punishing.
1. Balance Your Blood Sugar
One of the easiest and most effective ways to support your thyroid is to keep your blood sugar steady. Aim to include protein, healthy fat, and fiber at each meal. This helps stabilize insulin release, reduce physiological stress, sustain your energy, and create a more thyroid-friendly environment.
Looking for simple ways to balance your blood sugar? Check out my blog: [4 Tools for Blood Sugar Balance]
2. Heal Your Gut
Your gut is home to 70% of your immune system and plays a key role in thyroid hormone conversion. When you reduce inflammatory foods and support healthy gut microbes, you also support your thyroid. Work toward more whole foods, including some fermented options like sauerkraut or kefir, and you’ll improve nutrient absorption, reduce inflammation, and boost T4 to T3 conversion.
Curious how your gut microbiota influence your energy, digestion, and overall well-being? Dive into my blog: [Why Your Gut Microbiota Matter]
3. Nourish with Key Nutrients
Certain nutrients are essential for thyroid hormone production and conversion, and many people are unknowingly low. You can test your levels with your doctor, but even without labs, you can begin nourishing your thyroid by adding more of these foods:
Selenium: Brazil nuts, wild salmon, pasture-raised eggs
Zinc: Pumpkin seeds, beef, lentils
Magnesium: Leafy greens, almonds, bananas
Vitamin D: Sunlight, salmon, egg yolks
Vitamin C: Strawberries, cantaloupe, sweet potatoes
Food first is always the goal, but if you’re significantly deficient, targeted supplementation may be helpful under professional guidance.
Cruciferous veggies like broccoli, cabbage, and Brussels sprouts are packed with nutrients that support thyroid health. You don’t need to avoid them, just cook them gently to keep all the goodness and support your thyroid at the same time.
4. Cook Your Cruciferous Veggies
Broccoli, kale, cabbage, and Brussels sprouts are nutrient-dense, anti-inflammatory, and full of fiber. For some people with thyroid issues, raw forms may contribute goitrogens: natural compounds that interfere with iodine uptake. But there's no need to skip them. Lightly cooking these veggies reduces goitrogens while keeping all their benefits intact.
Curious about simple ways to include these veggies in your diet? Read my blog: [How Cruciferous Veggies Support Your Health]
5. Manage Stress Daily
Chronic stress is one of the most overlooked disruptors of thyroid function. Even just five minutes of deep breathing, a walk outside, or a few pages in your journal can help regulate your nervous system and reduce the impact of cortisol on thyroid hormones.
Looking for easy ways to balance your nervous system and reduce stress? Check out my blog: [Balancing Your Nervous System for Better Digestion]
6. Support Your Liver
Your liver helps convert T4 into active T3 while also clearing out what your body no longer needs. Support it by staying hydrated, loading up on leafy greens (especially cruciferous veggies), and limiting alcohol or ultra-processed foods when you can.
Want tips on supporting your liver naturally? Read my blog: [How to Support Liver Detox Naturally]
Supporting your liver (and by extension, your thyroid) doesn’t have to be bland or boring. Colorful, nutrient-packed meals like a purple cabbage salad with pomegranate and walnuts, can be both healing and delicious.
7. Get a Full Thyroid Panel
TSH alone doesn’t give the full picture. If you haven’t already, ask your provider for a more comprehensive panel that includes:
Free T3
Free T4
Reverse T3
TPO and TG antibodies (to screen for autoimmune thyroid disease)
If your provider isn’t open to deeper testing, a functional or integrative practitioner may be a better fit to help you get the full picture you deserve.
Final Thoughts: Real Healing Is Possible
If you’ve been told your only option is medication or felt dismissed when you asked why your thyroid isn’t working the way it should, know this: there’s more to the story.
Your thyroid doesn’t exist in a vacuum. It’s connected to your gut, your liver, your stress levels, and your nutrient status.
And every one of those areas can be supported.
I’ve seen it over and over again: when you support your gut and your body, the benefits ripple outward.
And guess what? It doesn’t take a complete overhaul.
Simple, sustainable shifts are where the real magic happens. You don’t need to be perfect. You just need to be curious and consistent.
No matter which of these steps you try, remember this:
Your path may be unique…but healing is absolutely possible.
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RESOURCES
Armstrong M, Asuka E, Fingeret A. Physiology, Thyroid Function. Updated March 13, 2023. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan–. Available from: https://www.ncbi.nlm.nih.gov/books/NBK537039/
© Stephanie Walsh and Walsh Approach, 2025. I pour a lot of care into creating this content, so please don’t copy or reuse it without permission. You’re always welcome to share excerpts or links if you give clear credit back to Stephanie Walsh and Walsh Approach.