Medical guidance required: Thyroid conditions require proper diagnosis and treatment from your GP or endocrinologist. Diet can support thyroid health but cannot replace medication if you have hypothyroidism or Hashimoto's. Always work with your healthcare team.
Your thyroid is a small butterfly-shaped gland in your neck that punches well above its weight. It produces hormones that regulate metabolism, energy, body temperature, heart rate, and dozens of other functions. When it's not working properly, you feel it everywhere.
Hashimoto's thyroiditis - an autoimmune condition where your immune system attacks the thyroid - is the most common cause of hypothyroidism (underactive thyroid) in the UK. It affects women far more than men and often runs in families.
While medication (levothyroxine) remains the cornerstone of treatment, nutrition plays a genuine supporting role. Here's what the research actually shows.
Key Nutrients for Thyroid Function
Your thyroid needs specific nutrients to produce hormones. Deficiencies in any of these can impair thyroid function, even if your thyroid itself is healthy.
Iodine
Your thyroid uses iodine to make T3 and T4 hormones. The UK population is borderline iodine deficient, particularly young women.
- Dairy products
- Fish and seafood
- Eggs
- Seaweed (in moderation)
Selenium
The thyroid contains more selenium per gram than any other organ. It's crucial for converting inactive T4 to active T3.
- Brazil nuts (1-2 daily)
- Fish and shellfish
- Meat and poultry
- Eggs
Zinc
Zinc is needed for thyroid hormone production and helps your cells respond to those hormones properly.
- Meat and shellfish
- Legumes and beans
- Nuts and seeds
- Dairy
Iron
Iron deficiency is common in hypothyroidism and can worsen symptoms. The enzyme that produces thyroid hormones requires iron.
- Red meat
- Beans and lentils
- Spinach (with vitamin C)
- Fortified cereals
The Brazil nut strategy: Just 1-2 Brazil nuts daily provides your entire selenium requirement. Some studies show selenium supplementation may reduce thyroid antibodies in Hashimoto's patients, though more research is needed.
Hashimoto's-Specific Considerations
Because Hashimoto's is an autoimmune condition, the dietary approach differs slightly from general thyroid support. The goal is reducing inflammation and potentially calming immune system overactivity.
What Some Hashimoto's Patients Find Helpful
These aren't universal recommendations - individual responses vary significantly:
- Anti-inflammatory eating: Mediterranean-style diet rich in omega-3s, vegetables, and olive oil
- Gluten consideration: Some (not all) Hashimoto's patients have coeliac disease or gluten sensitivity - worth testing if you have gut symptoms
- Blood sugar stability: Balanced meals prevent energy crashes that can worsen fatigue
- Gut health focus: Emerging research links gut microbiome health to autoimmune conditions
The Gluten Question
You'll see a lot of advice online telling Hashimoto's patients to go gluten-free. The reality is more nuanced.
There IS an established link between Hashimoto's and coeliac disease - having one autoimmune condition increases risk of others. If you have unexplained gut symptoms, getting tested for coeliac disease makes sense.
For Hashimoto's patients without coeliac disease, the evidence for gluten-free eating is mixed. Some people report feeling better; controlled studies haven't consistently shown benefit. If you want to try it, do so for 3-4 months and assess honestly whether you feel different.
Foods That Support Thyroid Health
Prioritise These
The Goitrogen Question
Goitrogens are compounds in certain foods that can interfere with thyroid function. They're found in cruciferous vegetables (broccoli, cauliflower, cabbage, Brussels sprouts, kale) and soy products.
Should you avoid them? Almost certainly not.
The Reality About Goitrogens
The goitrogen concern is largely overblown for most people:
- Cooking reduces goitrogens significantly - steaming, boiling, and sautéing all help
- You'd need to eat enormous amounts of raw cruciferous vegetables to affect thyroid function
- The nutritional benefits far outweigh risks - these vegetables are excellent for overall health
- Exception: If you're severely iodine deficient AND eating large amounts raw, there could be an issue
Bottom line: Eat your broccoli. Just don't juice entire heads of raw cabbage daily.
Soy and Thyroid
Soy contains both goitrogens and compounds that may interfere with thyroid medication absorption. The practical advice:
- Moderate soy consumption is fine for most people with thyroid conditions
- If taking levothyroxine, separate it from soy products by at least 4 hours
- Fermented soy (tempeh, miso) may be better tolerated
- Very high soy intake (multiple servings daily) may warrant monitoring
Medication Timing Matters
If you take thyroid medication, when and how you take it affects absorption significantly:
- Take on empty stomach: At least 30-60 minutes before breakfast
- Avoid calcium supplements nearby: Separate by 4 hours - calcium binds thyroid medication
- Same for iron supplements: Take at a different time of day
- Coffee delays absorption: Wait at least 30 minutes after taking medication
- Consistency matters: Take at the same time daily for stable levels
High-fibre timing: Very high-fibre meals can reduce medication absorption. If you eat a lot of fibre, be consistent about it so your dose accounts for this.
Weight Management Challenges
Weight gain is a frustrating symptom of hypothyroidism, and losing weight can feel impossible until thyroid levels are optimised. Some realities:
- Get levels optimised first: Weight loss is genuinely harder with untreated hypothyroidism
- Metabolism does slow: But typically by 100-300 calories daily, not thousands
- Protein is particularly important: Helps maintain muscle mass and supports metabolism
- Be patient: Weight may redistribute as thyroid levels normalise
- Strength training helps: Building muscle supports metabolic rate
Sample Day of Eating
What thyroid-supportive eating might look like in practice:
- Breakfast: Eggs with spinach and smoked salmon, wholegrain toast (rich in iodine, selenium, iron)
- Lunch: Grilled chicken salad with mixed greens, quinoa, olive oil dressing, and pumpkin seeds (zinc, anti-inflammatory fats)
- Snack: Greek yoghurt with berries and 1-2 Brazil nuts (selenium, iodine, antioxidants)
- Dinner: Baked cod with roasted vegetables and brown rice (iodine, fibre, balanced nutrition)
Notice what this isn't: restrictive, complicated, or requiring special "thyroid foods." It's simply balanced eating with attention to key nutrients.
The bottom line: Thyroid health is supported by adequate iodine, selenium, zinc, and iron - nutrients best obtained through varied, balanced eating. Avoid extreme diets, ensure key nutrient intake, take medication correctly, and work with your healthcare team. The thyroid responds better to consistency than perfection.
References
- Ventura, M., et al. (2017). Selenium and Thyroid Disease: From Pathophysiology to Treatment. International Journal of Molecular Sciences
- Rayman, M.P. (2019). Multiple nutritional factors and thyroid disease. Best Practice & Research Clinical Endocrinology & Metabolism
- Chahardoli, R., et al. (2020). Gluten-free diet and Hashimoto's thyroiditis: a systematic review. Journal of Endocrinological Investigation
- British Thyroid Foundation. (2023). Diet and the Thyroid.
- NHS. (2024). Underactive thyroid (hypothyroidism).
