Understanding the Thyroid: Your Guide to Gut and Thyroid Health

OlaKrawczyk
Aug 13
3 min read

Updated: Sep 24

Your thyroid might be small, but it plays a powerful role in your overall health. This butterfly-shaped gland in your neck regulates metabolism, energy levels, temperature, digestion, and hormone balance.

When your thyroid isn’t functioning well — whether it’s underactive (hypothyroidism) or overactive (hyperthyroidism) — you might notice symptoms across multiple systems of your body. One area that’s deeply connected to thyroid health is your gut.

Common Signs Your Thyroid May Be Struggling

Thyroid dysfunction can be sneaky. It often develops slowly and shows up through a mix of physical, digestive, and emotional symptoms.

You might experience:

Fatigue or low energy
Weight gain or difficulty losing weight
Constipation, bloating, reflux, or IBS-like symptoms
Brain fog, poor memory, forgetfulness
Anxiety, low mood, or irritability
Heart palpitations
Dry skin, hair loss, or thinning hair
Cold hands and feet
Muscle aches and joint pain
Frequent colds or low immunity

How Your Gut Influences Your Thyroid

The relationship between your gut and thyroid is a two-way street:

Nutrient Absorption: Your gut is where you absorb key nutrients for thyroid hormone production, including iodine, selenium, zinc, iron, and B vitamins. If gut health is compromised (due to inflammation, dysbiosis, or leaky gut), you may not absorb these effectively.
Immune Regulation: Around 70% of your immune system lives in your gut. Autoimmune thyroid conditions such as Hashimoto’s thyroiditis or Graves’ disease are influenced by immune activity, which can be modulated by your gut microbiome.
Inflammation Control: Chronic gut inflammation can drive systemic inflammation, affecting thyroid hormone conversion and signaling.
Hormone Conversion & Detoxification: Most inactive thyroid hormone (T4) is converted to its active form (T3) in the liver, which also plays a central role in detoxification. Additionally, the gut plays an important role in thyroid hormone conversion — healthy gut bacteria help convert T4 into T3 and also influence the balance of other thyroid-related compounds, such as reverse T3 (rT3).

For optimal thyroid function, both liver health and gut health need to be supported. Disruptions in either can reduce T3 production and contribute to symptoms of low thyroid function.

How Thyroid Dysfunction Impacts Gut Health

Just as gut health can influence the thyroid, thyroid issues can disrupt gut function:

Slower digestion in hypothyroidism can lead to constipation, bloating, and microbial imbalances.
Faster transit time in hyperthyroidism can cause diarrhea and nutrient deficiencies.
Altered stomach acid levels can change the gut environment, impacting digestion and microbiome balance.

Supporting Your Gut–Thyroid Axis

A tailored approach can help support both thyroid function and digestive health:

Eat nutrient-dense whole foods: Include sources of selenium (Brazil nuts), zinc (pumpkin seeds), iodine (seaweed, fish), and anti-inflammatory omega-3s.
Support your microbiome: Include a variety of fibre-rich plant foods and fermented foods (unless contraindicated).
Identify food triggers: For some people, gluten or dairy can drive inflammation; a structured elimination and reintroduction approach may help.
Manage stress: High stress impacts both gut and thyroid health via the HPA axis.
Test, don’t guess: Comprehensive thyroid panels and microbiome testing (such as metagenomic analysis) can uncover imbalances and guide personalised strategies.

The Bottom Line

If you’ve been experiencing a combination of digestive issues and symptoms of thyroid dysfunction, it’s worth looking at both together. The gut–thyroid connection means that by supporting one, you often help the other.

💬 I help clients improve both their gut and thyroid health using evidence-based, personalised nutrition plans.

📅 Book a consultation here and take the first step towards restoring your energy, digestion, and hormone balance.