6 Foods That Negatively Affect Your Thyroid – What to Avoid or Limit

Soy contains isoflavones (such as genistein), which are phytoestrogens — plant compounds that can:

Blocks thyroid peroxidase (TPO) , an enzyme necessary for the production of thyroid hormones
Interferes with the absorption of thyroid medications
Increased risk of hypothyroidism , especially in people with low iodine intake

This is particularly concerning in the case of:

People with Hashimoto’s thyroiditis
People taking levothyroxine (wait 4 hours after taking the medication before consuming soy)

🟢 Tip:
Fermented soybeans (e.g., miso, tempeh, natto ) are less problematic in moderation.
Limit your intake of unfermented soybeans if you have thyroid issues
❌ 3. Gluten

Food products worth paying attention to:

Bread, pasta, cereals, baked goods, beer (anything with wheat, barley, rye)

For people with Hashimoto’s disease (the most common cause of hypothyroidism), gluten may be a major trigger .

Why?
The gluten protein, gliadin , looks similar to thyroid tissue.
In sensitive individuals, the immune system can attack the thyroid through molecular mimicry .

Research shows a strong link between celiac disease and autoimmune thyroid disease .
🟢 Tip:
Even if you don’t have celiac disease, trying a gluten-free diet (for 4-6 weeks) can reduce inflammation and improve thyroid antibody levels.
❌ 4. Refined sugar and processed foods