Thyroid Health and Digestion: How Thyroid Dysfunction Impacts Gut Health, Energy, and Hormones
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Table of Contents
Why Thyroid Health Deserves Attention
What is Thyroid Dysfunction?
Common Symptoms of Thyroid Imbalances
How Thyroid Dysfunction Affects Digestion, Weight, and Hormones
Evidence-Based Nutrition and Lifestyle Support
Nutrition Strategies
Supplements: What to Consider (and What to Avoid)
Lifestyle & Practical Tips
Final Thoughts & How Katie Chapmon Nutrition Can Support You
References
Why Thyroid Health Deserves Attention
January is Thyroid Awareness Month, making it the perfect time to talk about a small gland that has a big impact on how your body functions — including digestion.
If you’ve been struggling with bloating, constipation, fatigue, stubborn weight changes, or feeling “off” despite doing many of the right things, your thyroid may be part of the picture. Thyroid dysfunction often shows up subtly and can be overlooked, especially when symptoms overlap with stress, gut issues, or hormonal changes.
This article will:
Explain how thyroid dysfunction affects digestion, energy, weight, and hormones
Clarify the gut–thyroid connection
Share actionable, evidence-based nutrition strategies
Outline how Katie Chapmon Nutrition can support thyroid and digestive health together
What Is Thyroid Dysfunction?
The thyroid is a butterfly-shaped gland located in the neck that produces hormones responsible for regulating metabolism, energy production, body temperature, digestion, and hormone signaling throughout the body.
The most common types of thyroid dysfunction include:
Hypothyroidism: an underactive thyroid (low thyroid hormone production)
Hyperthyroidism: an overactive thyroid (excess thyroid hormone production)
Autoimmune thyroid conditions, such as Hashimoto’s thyroiditis or Graves’ disease
Hypothyroidism, particularly autoimmune-related, is the most common form and disproportionately affects women.
According to the American Thyroid Association, approximately 20 million Americans have some form of thyroid disease, and up to 60% may be undiagnosed.
Common Symptoms of Thyroid Imbalances
Thyroid dysfunction can affect nearly every system in the body. Common symptoms include:
Fatigue or low energy
Constipation or slowed digestion
Bloating or abdominal discomfort
Unexplained weight gain or difficulty losing weight
Cold intolerance
Hair thinning or hair loss
Dry skin
Irregular menstrual cycles
Brain fog or difficulty concentrating
Because many of these symptoms overlap with gut or hormone concerns, thyroid health is often missed unless specifically evaluated.
How Thyroid Dysfunction Affects Digestion, Weight, and Hormones
The thyroid does not operate in isolation — it works closely with the digestive system, adrenal glands, and reproductive hormones.
Thyroid Health and Digestion
Thyroid hormones play a direct role in gut motility, or how quickly food moves through the digestive tract.
Low thyroid hormone levels can slow digestion, contributing to constipation, bloating, and discomfort.
Slower motility can also impact the gut microbiome, potentially leading to bacterial imbalances.
Additionally, adequate stomach acid is necessary for proper digestion and nutrient absorption. Thyroid dysfunction has been associated with reduced stomach acid, which may contribute to bloating, reflux, or nutrient deficiencies.
Thyroid Health and Weight
Weight changes associated with thyroid dysfunction are often misunderstood.
While thyroid hormones do influence metabolism, weight gain or loss is rarely caused by thyroid hormones alone. Factors such as gut health, blood sugar balance, inflammation, and stress hormones all play a role.
Supporting digestion, muscle mass, and metabolic health holistically is often more effective than focusing on calorie restriction.
Thyroid Health and Hormones
The thyroid closely interacts with:
Cortisol (stress hormone)
Estrogen and progesterone
Insulin and blood sugar regulation
Imbalances in one system can create a ripple effect, making a whole-body approach essential — especially for long-term symptom improvement.
Evidence-Based Nutrition and Lifestyle Support
Nutrition Strategies for Thyroid and Gut Health
Rather than restricting how you eat, thyroid support focuses on nutrient adequacy and digestive support.
Prioritize protein
Protein supports thyroid hormone production, blood sugar balance, and muscle mass. Aim for a protein source at each meal.
Support micronutrient intake
Key nutrients involved in thyroid health include:
Iodine (found in seafood, dairy, iodized salt)
Selenium (Brazil nuts, seafood, eggs)
Zinc (meat, shellfish, seeds)
Iron (meat, legumes, leafy greens)
Nutrient deficiencies are common in people with thyroid dysfunction and they can both contribute to symptoms and make them harder to improve.
Slower thyroid function can reduce stomach acid, digestive enzyme output, and gut motility. This makes it harder to break down and absorb key nutrients from food. In addition, chronic inflammation, gut imbalances, restrictive eating, and long-term stress can further impair absorption and increase nutrient needs.
When nutrients like iron, selenium, vitamin D, or B vitamins are low, symptoms such as fatigue, hair thinning, cold intolerance, constipation, and brain fog may worsen. This is why identifying and addressing deficiencies – rather than guessing or supplementing blindly – is so important.
Include gut-supportive fiber
Fiber plays a key role in supporting the gut microbiome, regulating digestion, and promoting regular bowel movements – all of which can be impacted in hypothyroidism.
That said, fiber can be a double-edged sword. For some people, especially those with slowed digestion, bloating, or constipation, adding large amounts of fiber too quickly can worsen symptoms. This may happen because food is moving more slowly through the gut or because the microbiome is not yet able to tolerate certain fibers.
A more personalized approach matters. Gradually increasing fiber, choosing easier-to-digest sources (such as cooked vegetables, oats, chi, or ground flax), and pairing with adequate fluids and protein can make it more supportive rather than irritating.
Limit ultra-processed foods
Highly processed foods can contribute to inflammation, blood sugar dysregulation, and gut imbalance. These factors may interfere with thyroid hormone signaling and worsen symptoms like fatigue, cravings, and digestive discomfort.
Focusing on mostly whole, minimally processed foods helps support stable energy, gut health, and hormone balance – without needing to be overly restrictive.
Supplements: What to Consider (and What to Avoid)
Supplements can be helpful — but only when individualized. More is not always better, and the goal is to support the body, not overwhelm it.
Potentially supportive supplements may include:
These may be helpful for some individuals, depending on labs, symptoms, and overall health:
Selenium (typically 100-200 mcg/day): Supports thyroid hormone conversion and antioxidant activity. Higher doses are not always better and should be avoided unless guided by a professional. )
Vitamin D: Low levels are common and may impact immune and thyroid health. Dosage should ideally be based on blood levels.
Iron (only if deficient): Iron deficiency can impair thyroid hormone production and worsen fatigue. Supplementation should always be guided by labs.
Probiotics: May support digestion and regularity when gut motility is sluggish or digestion feels irregular, though strains and timing matter.
Supplement needs vary widely. What works for one person may not be appropriate for another.
What to avoid:
High-dose iodine supplementation without medical guidance
“Thyroid booster” supplements containing undisclosed or hormone-like ingredients
Excessive restriction of entire food groups without a clear clinical reason
Always consult with a qualified healthcare professional before starting any new supplement.
Lifestyle & Practical Tips
Thyroid health is deeply influenced by daily habits.
Manage stress: Chronic stress can impair thyroid hormone conversion
Support sleep: Poor sleep disrupts hormone signaling
Eat consistently: Skipping meals may worsen fatigue and blood sugar swings
Move gently: Over-exercising can be counterproductive in thyroid dysfunction
Sustainable routines support both thyroid function and digestive health over time.
Final Thoughts & How Katie Chapmon Nutrition Can Support You
Thyroid dysfunction can impact digestion, energy, weight, and hormones in complex ways — but support doesn’t have to be overwhelming or restrictive.
At Katie Chapmon Nutrition, we take a whole-body, gut-forward approach to thyroid health by:
Addressing digestion and nutrient absorption
Supporting sustainable nutrition habits
Evaluating whether gut microbiome testing or other functional tools may be helpful
Creating personalized plans that fit real life
If you’re navigating thyroid symptoms and want clarity:
Sign up for our newsletter for thyroid and gut health insights
Book a free 30-minute meet & greet consultation
Learn more about gut microbiome testing and individualized support
Your thyroid doesn’t work alone — and neither should your care.
References
American Thyroid Association. (n.d.). Thyroid information. https://www.thyroid.org
Harvard T. H. Chan School of Public Health. (n.d.). Thyroid and nutrition. https://www.hsph.harvard.edu
National Institutes of Health. (n.d.). Thyroid diseases. https://www.niddk.nih.gov
Virili, C., Centanni, M., Santaguida, M. G., Gargano, L., Brusca, N., De Vito, C., Capriello, S., Donato, G., & Gargano, L. (2019). Gut microbiota and thyroid interaction. Frontiers in Endocrinology, 10, 287. https://doi.org/10.3389/fendo.2019.00287
Published: January 28th, 2026
This blog post was written by Ella Holmes, an administrative assistant at Katie Chapmon Nutrition. Ella works closely with Katie Chapmon and Amanda Sikkema, Registered Dietitians who are currently accepting new clients.
