The Thyroid-Gut Connection: How Low Thyroid Function Impacts Bloating, Constipation & Digestion

If you’ve ever felt like no matter what you eat, you still end up bloated, constipated, exhausted, and frustrated—you're not alone. So many women I work with have “done all the things”: tried cutting out gluten, dairy, or FODMAPs, taken probiotics, done endless lab work… and still feel like their body is fighting them.

Here’s a piece of the puzzle that’s often overlooked: your thyroid and how it connects to your gut.

Let’s dive in.

💛 What Is the Thyroid & What Does It Do?

Your thyroid is a small, butterfly-shaped gland at the base of your neck. It may be tiny, but it plays a massive role in your health—especially when it comes to digestion, metabolism, energy, and even mood.

The thyroid produces two key hormones:

• T4 (thyroxine) – your storage hormone

• T3 (triiodothyronine) – your active hormone (aka the one that actually does stuff in your body)

T4 gets converted to T3, mostly in your liver and gut. So if your gut isn’t functioning well, guess what? Your thyroid hormones may not be either.

🌿 Gut Health = Immune Health

Over 70% of your immune system lives in your gut (yep—that much). Your gut lining is meant to act as a barrier: letting in nutrients, keeping out toxins and pathogens.

But when stress, food sensitivities, infections, or inflammation hit hard, that lining can become more permeable—this is often called leaky gut.

When the gut becomes “leaky,” your immune system gets triggered. This chronic immune activation can:

• Lead to autoimmune conditions like Hashimoto’s (a common cause of hypothyroidism in women)

• Interfere with thyroid hormone conversion and absorption

• Create more inflammation, which slows digestion and leads to—you guessed it—more bloating and constipation

😣 The Stress Factor

Let’s talk about stress. I know, easier said than done, but it seriously matters.

Chronic stress messes with your cortisol levels (your main stress hormone), which:

• Slows down digestion

• Decreases your stomach acid (hello maldigestion + gas)

• Impairs thyroid hormone production and conversion

• Worsens leaky gut and inflammation

Stress also makes your nervous system stay in “fight or flight” mode instead of “rest and digest” mode. And guess what? You literally can’t poop properly in fight or flight.

🚽 Constipation + Low Thyroid: A Vicious Cycle

If you’re dealing with constipation, your thyroid might be at the root of it. Low thyroid function slows down your digestive motility—aka how fast food moves through your system. This leads to:

• Feeling “not empty” after a bowel movement

• Bloating and gas

• Toxins being reabsorbed (gross but true)

• Estrogen not getting cleared properly (which messes with hormones even more)

And get this: slow digestion can also worsen thyroid function by creating more inflammation and nutrient depletion. It’s a cycle—and it’s exhausting.

🥦 Nutrients That Matter (and Why You're Probably Not Absorbing Them)

Your thyroid needs certain nutrients to function, including:

• Selenium (helps convert T4 to T3)

• Zinc (supports immune health + hormone production)

• Iron (needed for energy + thyroid hormone synthesis)

• Vitamin A, D, and B12

• Iodine (only in proper balance—too much or too little can be problematic)

But here’s the catch: if you have leaky gut, low stomach acid, or dysbiosis (imbalanced gut bacteria), you’re probably not absorbing these nutrients well—no matter how clean you eat.

🧪 The Truth About Thyroid Testing

Most standard thyroid tests only look at TSH (thyroid stimulating hormone). But that’s just one piece. To really understand what’s going on, you need a full thyroid panel, including:

• TSH

• Free T4

• Free T3

• Reverse T3

• Thyroid antibodies (TPO and TGAb) to check for autoimmune thyroid disease

And even if your labs are “normal,” that doesn’t mean your body is functioning optimally. You deserve better than being told, “everything looks fine” when you clearly don’t feel fine.

✨ Ready to Get to the Root?

If you’re reading this and thinking, “This is me,”—you’re not alone. And no, you're not crazy or broken.

Inside my signature program, The Bloat-Free Method, we go deep into gut-healing, thyroid support, and hormone balance—with realistic steps and a clear plan. You’ll get the tools, testing, and personalized guidance you need to finally feel like yourself again.

🌿 If you’re ready to dig deeper and feel better, apply here to work with me inside The Bloat Free Method Program.