Nutrition for Hashimoto's and hypothyroidism - what helps the thyroid gland?

The thyroid gland is a small, butterfly-shaped organ in the neck that produces hormones and controls the metabolism. In Hashimoto's thyroiditis, the immune system attacks the thyroid gland, causing chronic inflammation that gradually leads to hypothyroidism (under-functioning). This can lead to tiredness, weight gain, sensitivity to cold, hair loss, dry skin and mood swings. Many sufferers ask themselves: What can I do through my diet to support my thyroid gland? In this article, we summarize scientific findings, show nutritional strategies and give tips for everyday life.

1 How the thyroid gland works and why Hashimoto's is different

The thyroid gland produces the hormones thyroxine (T4) and triiodothyronine (T3). These hormones control metabolism, body temperature and many other functions. Their release is regulated via the pituitary gland (hypophysis) by the thyroid stimulating hormone (TSH). In Hashimoto's, the immune system produces antibodies against the thyroid gland; antibodies against thyroid peroxidase (TPOAb) and against thyroglobulin (TGAb) are the most common. This leads to chronic inflammation and gradual destruction of the organ. This is why many sufferers need L-thyroxine for the rest of their lives. However, there is evidence that diet, micronutrients and lifestyle can influence the inflammation and support the residual function of the thyroid gland.

Important: In the EU, food supplements may only be advertised with approved health claims. Statements such as "cures Hashimoto's" or "prevents hypothyroidism" are prohibited. For each substance that does not have an officially approved claim, we therefore add the note that the link is being scientifically investigated but has not (yet) been confirmed by the European Food Safety Authority (EFSA).

2 Iodine - basic building block of thyroid hormones

Iodine is essential for the synthesis of T3 and T4. Without sufficient iodine, the thyroid gland is unable to produce hormones, resulting in hypothyroidism. In Germany, table salt with added iodine is considered the most important source of iodine; sea fish, milk and eggs provide additional amounts. According to EFSA recommendations, the daily iodine intake for adults is around 150 µg; pregnant women and breastfeeding mothers need more. An approved health claim reads: "Iodine contributes to the normal production of thyroid hormones and to normal thyroid function".

In the case of Hashimoto's, the issue of iodine is controversial: some studies show that too much iodine can increase inflammation. In areas with very high iodine intake (e.g. through algae supplements), the number of autoimmune diseases increases. Conversely, however, there must be no iodine deficiency, as this can exacerbate hypothyroidism. A moderate iodine level is the key. Salt with added iodine, sea fish once or twice a week and possibly a multivitamin are usually sufficient. High-dose algae supplements are not recommended.

3 Selenium - a protective shield for the thyroid gland

Selenium is an essential trace element. It is a component of important enzymes such as glutathione peroxidase and deiodinases, which regulate the conversion of T4 to T3. Selenium also protects the thyroid gland from oxidative stress. The EFSA allows the statement: "Selenium contributes to normal thyroid function and to the protection of cells from oxidative stress."

A large systematic review with 35 randomized studies showed that selenium supplements (often 200 µg selenomethionine daily) reduced TSH and TPO-Ab levels and lowered the oxidative stress marker malondialdehyde in people with Hashimoto's without thyroid hormone replacement [1]. At the same time, free T3/T4 levels hardly changed and there were no serious side effects. These results suggest that selenium may be helpful in Hashimoto's patients with proven selenium deficiency. However, the heterogeneity of the studies was high; experts therefore recommend determining the blood level before selenium supplementation and discussing the intake with the doctor.

Smaller studies also point in the same direction: in a pilot study, men with Hashimoto's were given either selenomethionine (200 µg/day) or vitamin D. Both groups showed low selenium levels after three months. Both groups showed lower antibody titres and a higher SPINA-GT index after three months [9]. A second pilot study, which combined gluten avoidance with selenium, also found a greater reduction in antibodies [8]. Nevertheless, the following applies: only supplement if there is a deficiency and do not permanently increase the dosage above 200 µg/day, as otherwise there is a risk of side effects.

4 Vitamin D - immune modulator and mood booster

Vitamin D is primarily known for bone metabolism, but it also plays a role in the immune system. The EFSA allows the claim: "Vitamin D contributes to the normal function of the immune system." Many people with Hashimoto's suffer from low 25-hydroxyvitamin D levels, especially in winter or when there is little sunlight.

A recent meta-analysis of twelve randomized trials with 862 participants showed that vitamin D supplementation significantly reduced TPO-Ab and TG-Ab (standardized mean differences -1.084 and -0.996, respectively), reduced TSH levels and increased free T3/T4 levels. Active vitamin D and a duration of twelve weeks were particularly effective. The study concluded that vitamin D can have positive effects on autoimmunity in Hashimoto's [2]. A combined intake of vitamin D and selenium appears to have a synergistic effect, as a small pilot study from Poland suggests [9]. As vitamin D deficiency is widespread in our latitudes, the level (25(OH)D) should be measured and, if necessary, corrected by supplementation (e.g. 1000-2000 IU/day). Overdoses should be avoided - the normal range is around 50-75 nmol/l.

5 Iron, zinc and other micronutrients

Iron

Iron is responsible for the formation of hemoglobin, contributes to normal oxygen transport and normal energy production. It is also important for the enzyme thyroperoxidase. Studies show that iron deficiency - especially in women - is associated with low T3/T4 and elevated TSH. Combined treatment with L-thyroxine and iron leads to better symptom control than taking hormones alone. Since an official health claim is "iron helps reduce tiredness and fatigue", iron-rich foods such as red meat, pulses, millet and dark green vegetables can reduce tiredness. A blood test (ferritin) should be carried out in the case of Hashimoto's; supplementation may be useful in the event of a deficiency. However, excessive amounts of iron can be harmful.

Zinc

Zinc is a cofactor of numerous enzymes, has an antioxidant effect and supports the immune system. According to the EFSA, it contributes "to the normal function of the immune system" and "to the protection of cells from oxidative stress". Small observational studies indicate that zinc deficiency is common in hypothyroidism and that zinc supplements can improve the conversion of T4 to T3 [11]. However, the data is sparse; therefore, the relationship between zinc and thyroid function has not yet been confirmed by EFSA; further studies are needed. Good sources of zinc are oysters, meat, pumpkin seeds and oatmeal. Vegetarians should pay particular attention to their zinc intake.

Vitamin B12, B6, magnesium and omega-3 fatty acids

Vitamin B12 and B6 support energy metabolism and help to reduce fatigue. People with Hashimoto's are more likely to develop pernicious anemia (vitamin B12 deficiency), which is why a check-up is advisable. According to the EFSA, magnesium contributes to "normal muscle function and energy metabolism"; a deficiency can lead to muscle cramps, fatigue and sleep disorders. Omega-3 fatty acids (EPA and DHA) have anti-inflammatory properties; however, there is no approved claim for the thyroid gland. Fish, algae oil or high-quality supplements provide omega-3. As the link between omega-3 and Hashimoto's has not been confirmed by the EFSA, further research is needed.

6 Gluten-free diet - a blessing or a fad?

Gluten is a controversial issue in Hashimoto's. Cereals containing gluten, such as wheat, rye and barley, contain proteins that can trigger an immune reaction in people with a genetic predisposition. If coeliac disease is proven, a strict gluten-free diet is essential. But what about people who only have Hashimoto's?

A small Polish pilot study compared 34 women with Hashimoto's: half followed a gluten-free diet for six months, while the other half ate a normal diet. In the gluten-free group, anti-TPO and anti-TG antibodies decreased significantly and vitamin D levels increased slightly [8]. The SPINA-GT index, which describes thyroid production, improved. The authors concluded that a gluten-free lifestyle can reduce autoimmunity in some women. A recent systematic review from 2023 found a moderate but significant reduction in TPO-Ab and TG-Ab levels and a slight decrease in TSH in the overall analysis, while free T3 levels did not change [12]. However, the studies were heterogeneous.

Another problem: gluten-free products are often low in fiber and micronutrients. In addition, a strict elimination diet is socially stressful. Experts therefore recommend that a gluten-free trial lasting three to six months makes sense if it is supervised by a doctor and nutritional gaps are closed. If no improvement is noticed, gluten can be reintroduced. Without coeliac disease, there is no obligation for lifelong abstinence.

7 Mediterranean, Paleo and autoimmune diets

Mediterranean diet - colorful, fresh and balanced

The Mediterranean diet is based on fruit, vegetables, pulses, fish, olive oil, nuts and whole grains. It is rich in omega-3 fatty acids, polyphenols and antioxidants. In a randomized study of 40 Hashimoto's patients, four groups were compared: Mediterranean diet, gluten-free diet, Mediterranean gluten-free diet and control group. After three months, FT3 levels increased in all intervention groups and TSH levels as well as TPO-Ab and TG-Ab levels decreased [7]. In the Mediterranean and combined Mediterranean-gluten-free groups in particular, antibodies decreased significantly and body weight was reduced [7]. These results show that a low-inflammatory diet with plenty of vegetables, fruit, fish and good fats can relieve the thyroid gland. The advantages are the variety of foods and the good supply of micronutrients.

Paleo and autoimmune protocol (AIP)

The Paleo Hashimoto's program is based on a Stone Age diet and eliminates grains, dairy products, legumes, refined sugars and processed foods. The Autoimmune Protocol (AIP) goes even further and also excludes eggs, nuts, seeds and nightshade plants. The aim is to avoid pro-inflammatory foods and identify potential triggers.

A 10-week pilot study from the USA examined 17 women with Hashimoto's who followed an AIP diet in an online lifestyle program. After ten weeks, quality of life and symptom scores improved significantly; high-sensitivity CRP (inflammatory marker) decreased by 29%, but thyroid hormones remained stable; participants lost weight slightly and some were able to reduce their medication [5]. A Polish study with 28 people tested the AIP diet over twelve weeks. FT3, FT4 and TSH levels decreased (but remained within the normal range), thyroid volume decreased, weight decreased and well-being increased. However, TPO-Ab levels increased, while TG-Ab levels decreased slightly. The authors emphasized that longer observation and individualized food choices are necessary to enhance positive effects [6].

Conclusion: AIP and Paleo diets can improve inflammation parameters and quality of life in the short term. Due to the severe restrictions, they should only be implemented for a short time and under the supervision of a nutritionist. People with Hashimoto's who want to identify new triggers can try an elimination phase of 4-8 weeks and then gradually reintroduce foods. It is important to compensate for possible nutrient deficiencies (e.g. calcium, B vitamins) with suitable foods or supplements.

8. intestinal flora and thyroid - a new research perspective

In recent years, the intestine has become the focus of thyroid research. The gut microbiome influences the immune system and possibly also the thyroid gland. A bidirectional Mendelian randomization study with 26,342 people showed that a higher proportion of the bacterial genus Akkermansia reduces the risk of hypothyroidism (odds ratio 0.84). Conversely, hypothyroidism had no significant effect on the intestinal flora [3]. The authors assume that Akkermansia strengthens the intestinal barrier and inhibits inflammation. However, the connection has not yet been confirmed by the EFSA; further clinical studies and intervention trials with probiotics are required.

Another study integrated gut microbiome and transcriptome data. It found subtle changes in microbial diversity and an increased frequency of certain bacterial strains in early Hashimoto's patients and defined nine characteristic RNA markers that, in combination with the microbiome signatures, could identify the disease with an accuracy of 85% [4]. These results underline how closely the intestinal flora and thyroid are linked. It can be deduced from this that high-fiber foods (vegetables, fruit, legumes) and fermented products (sauerkraut, yoghurt, kefir) can promote intestinal diversity. However, the connection between "leaky gut" and thyroid disease has not been conclusively proven. Therefore, the influence of intestinal flora on Hashimoto's is an exciting field of research, but further studies are needed.

9 Lifestyle: stress management, exercise and sleep

It is not only diet that plays a role in chronic diseases, but also lifestyle. Stress can impair the immune system and promote inflammatory processes. Chronic stress increases cortisol levels, which in turn can inhibit the conversion of T4 to T3. Doctors therefore recommend methods of stress management: Yoga, meditation, breathing exercises and moderate exercise.

A systematic review of eight clinical trials found that yoga improves TSH, T3 and T4 levels, optimizes the lipid profile, increases heart rate variability, reduces anxiety and depression and improves quality of life. However, the studies were very heterogeneous, so that further randomized control studies are needed [10]. In addition to yoga, walking, cycling, swimming and strength training are also suitable. It is important not to overload yourself: in cases of severe hypothyroidism, a stress test should be carried out before starting more intensive training.

Sleep also plays a role: too little sleep increases inflammation markers and can slow down the metabolism. Make sure you get 7-8 hours of sleep per night. Avoiding alcohol, smoking and excessive sugar also has a positive effect. Sugar spikes put a strain on the pancreas and promote inflammation, which is why a sugar-free or low-sugar diet can relieve the thyroid gland.

10 Practical nutrition tips and recipes

Alkaline and low-inflammatory foods

• Vegetables and fruit: broccoli, spinach, carrots, beet, blueberries, apples - colorful and rich in antioxidants.

• High-quality proteins: Fish (e.g. salmon, mackerel), lean meat, pulses, tempeh and eggs.

• Healthy fats: Extra virgin olive oil, avocado, nuts, seeds (chia, linseed) and oily fish provide omega-3.

• Gluten-free whole grain products: Millet, buckwheat, quinoa, amaranth and gluten-free rolled oats.

• Fermented foods: sauerkraut, kimchi, kombucha and yoghurt support the intestinal flora.

Foods that some sufferers avoid

• Raw soy and cruciferous vegetables: Soybeans, raw cabbage, Brussels sprouts and rapeseed contain goitrogens, which can inhibit iodine absorption in large quantities. They are unproblematic when well cooked.

• Overly processed foods: Ready meals, sausages and snacks often contain trans fats, additives and lots of sugar.

• Excessive seaweed products: Some seaweeds (kombu, wakame) contain extremely high amounts of iodine. A portion of nori or wakame once a week is sufficient.

Ideas for the diet

Many people ask for "Hashimoto's recipes". Here are some simple examples:

• Breakfast: Gluten-free oatmeal with oat milk, chia seeds, blueberries and a spoonful of almond butter. Sweeten with cinnamon if required.

• Lunch: Colorful Buddha bowl: quinoa, steamed broccoli, roasted sweet potato cubes, chickpeas, avocado, red cabbage, olive oil and lemon dressing.

• Snack: plain yogurt or coconut yogurt with fermented sauerkraut or a handful of nuts.

• Dinner: Baked salmon with herbs, served with oven vegetables (peppers, zucchini, pumpkin) and a salad of rocket and radishes.

The dishes can also be modified to be gluten-free, lactose-free or paleo. If you are following an autoimmune diet, you can, for example, leave out nightshades (tomatoes, peppers, eggplants) and replace nuts with coconut products.

11. food supplements and product recommendations

Food supplements can be helpful if certain micronutrients are missing in the blood or if the diet does not cover all nutrients. It is important to determine the status (e.g. selenium, vitamin D, B12, ferritin) in the blood in advance and to discuss the intake with a doctor. The market offers numerous "Hashimoto supplements" or "thyroid balance" products. Look out for transparent declarations, moderate dosages and EU health claims.

Our product tip: XTRA FUEL Thyroid Balance capsules. These capsules contain a balanced combination of iodine, selenium, zinc, vitamin D and B vitamins in moderate doses. The micronutrients contained support the normal function of the thyroid gland and the immune system according to EFSA approved health claims (e.g. "Iodine contributes to the normal production of thyroid hormones", "Selenium contributes to normal thyroid function", "Vitamin D contributes to the normal function of the immune system"). Please note: Food supplements are not a substitute for a balanced diet and cannot replace medical treatment.

12. experience reports and dealing with expectations

Many sufferers share their Hashimoto's experience reports in forums and blogs. Some report a drastic improvement after going gluten-free, others swear by the autoimmune protocol, some hardly notice any changes. This spectrum makes it clear: Hashimoto's is individual. The genetic disposition, intestinal flora, stress level and life situation influence how the body reacts. Reports can provide suggestions, but they are no substitute for medical advice. A food diary helps to identify individual triggers (e.g. dairy products, nightshades, gluten). Anyone trying out drastic diets should only do so for a limited period of time and seek professional support to prevent deficiency symptoms.

13 Hashimoto's and the gut - how to understand Leaky Gut & Co.

The term "leaky gut" describes a permeable intestinal barrier. Some hypotheses assume that Hashimoto's causes increased intestinal bacteria, food components or endotoxins to enter the bloodstream, which activates the immune system. The above-mentioned study on integrative microbiome and transcriptome analysis, for example, found an imbalance in the gut microbiota and evidence of immune and infection pathways [4]. Nevertheless, it remains unclear whether "leaky gut" is the cause or consequence of autoimmunity. There is no approved health claim for "leaky gut" in the EU. Therefore, the link between intestinal permeability and thyroid disease has not yet been confirmed by the EFSA; further studies are required. If you want to support your gut health, you should integrate a high-fiber diet, fermented foods and stress-reducing measures.

14 Treatment and medical support

Hashimoto's treatment usually consists of the substitution of L-thyroxine if the thyroid gland does not produce enough hormones. The dose is adjusted individually based on TSH, fT3/fT4 and symptoms. Some doctors also use nutritional supplements or recommend dietary changes. It is important to have regular blood checks, to keep the medication level constant (tablet taken in the morning on an empty stomach, 30 minutes before breakfast) and to discuss potential interactions (e.g. taking calcium, iron or soy products) with the doctor.

Alternative therapies such as detoxification, "thyroid detox" or high-dose vitamins are advertised on the internet, but have no scientific basis and involve risks. Detoxification of the thyroid gland in the sense of a radical cure is not necessary; the liver and kidneys take care of detoxification processes. There are also no authorized statements that "Hashimoto's cure" is possible through certain detoxification cures.

15 Summary and outlook

A change in diet can improve the quality of life in Hashimoto's and hypothyroidism, reduce inflammation and compensate for micronutrient deficiencies. Scientific studies show that:

• Selenium supplementation in moderate doses lowers TSH and antibody levels [1].

• Vitamin D can reduce autoimmunity and improve metabolism [2].

• A gluten-free diet leads to lower antibody titres in some women [8].

• A Mediterranean or Mediterranean-gluten-free diet has a positive effect on hormone balance and weight [7].

• AIP or Paleo programs can increase quality of life and lower inflammatory markers in the short term [5], [6].

• The gut microbiome plays a role, but the connections are not yet fully understood [3], [4].

• Yoga and stress reduction improve thyroid hormones and well-being [10].

There is no "miracle diet" for Hashimoto's. Instead, an individualized approach is recommended: balanced, preferably unprocessed foods, sufficient intake of iodine, selenium, vitamin D, iron and zinc, avoidance of nutrient deficiencies, moderate exercise and stress management. If you want to try out certain diets, you should do so for a limited time and in cooperation with medical professionals. This is the best way to support the thyroid gland in Hashimoto's and hypothyroidism.

Last but not least: Please always discuss your diet and supplements with your doctor or nutritionist. This article is for information purposes only and does not replace medical advice.

List of sources

1. Huwiler, V. V., Maissen-Abgottspon, S., Stanga, Z., Mühlebach, S., Trepp, R., Bally, L., & Bano, A. (2024). Selenium Supplementation in Patients with Hashimoto Thyroiditis: A Systematic Review and Meta-Analysis of Randomized Clinical Trials. Thyroid, 34(3), 295-313. DOI: 10.1089/thy.2023.0556.

2. Tang, J., Shan, S., Li, F., & Yun, P. (2023). Effects of vitamin D supplementation on autoantibodies and thyroid function in patients with Hashimoto's thyroiditis: A systematic review and meta-analysis. Medicine (Baltimore), 102(52), e36759. DOI: 10.1097/MD.0000000000036759.

3. Shi, C., Chen, J., He, S., Zhang, Y., Zhang, Y., & Yu, L. (2024). Cross-talk between the gut microbiota and hypothyroidism: a bidirectional two-sample Mendelian randomization study. Frontiers in Nutrition, 11, 1286593. DOI: 10.3389/fnut.2024.1286593.

4. Li, M., Chen, K., Chen, Y., Zhang, L., Cui, Y., Xiao, F., Liu, Z., et al. (2024). Integrative analysis of gut microbiome and host transcriptome reveal novel molecular signatures in Hashimoto's thyroiditis. Journal of Translational Medicine, 22(1), 1045. DOI: 10.1186/s12967-024-05876-3.

5. Abbott, R. D., Sadowski, A., Alt, A. G., & colleagues (2019). Efficacy of the Autoimmune Protocol Diet as Part of a Multi-disciplinary, Supported Lifestyle Intervention for Hashimoto's Thyroiditis. Cureus, 11(4), e4556. DOI: 10.7759/cureus.4556.

6. Ihnatowicz, P., Gębski, J., & Drywień, M. E. (2023). Effects of Autoimmune Protocol (AIP) diet on changes in thyroid parameters in Hashimoto's disease. Annals of Agricultural and Environmental Medicine, 30(3), 513-521. DOI: 10.26444/aaem/166263.

7. Ülker, M. T., Arıtıcı Çolak, G., & Baş, M. (2023). Evaluation of the effect of gluten-free diet and Mediterranean diet on autoimmune system in patients with Hashimoto's thyroiditis. Food Science & Nutrition, 12(2), 1180-1188. DOI: 10.1002/fsn3.3833.

8. Krysiak, R., Szkróbka, W., & Okopień, B. (2019). The effect of gluten-free diet on thyroid autoimmunity in drug-naïve women with Hashimoto's thyroiditis: A pilot study. Experimental and Clinical Endocrinology & Diabetes, 127(7), 417-422. DOI: 10.1055/a-0653-7108.

9. Krysiak, R., Szkroba, W., & Okopień, B. (2019). The effect of vitamin D and selenomethionine on thyroid antibody titers, hypothalamic-pituitary-thyroid axis activity and thyroid function tests in men with Hashimoto's thyroiditis: A pilot study. Pharmacological Reports, 71(2), 243-247. DOI: 10.1016/j.pharep.2018.10.012.

10. Bhandari, R. B., & Mahto, P. K. (2024). Effect of Yoga Therapy on Hypothyroidism: A Systematic Review. Annals of Neurosciences, 32(3), 207-218. DOI: 10.1177/09727531241282516.

11. Shulhai, A.-M., Rotondo, R., Petraroli, M., Patianna, V., Predieri, B., Iughetti, L., & Esposito, S. (2024). The Role of Nutrition on Thyroid Function. Nutrients, 16(15), 2496. DOI: 10.3390/nu16152496.

12. Piticchio, T., Frasca, F., Malandrino, P., Trimboli, P., Carrubba, N., Tumminia, A., Vinciguerra, F., & Frittitta, L. (2023). Effect of gluten-free diet on autoimmune thyroiditis progression in patients with no symptoms or histology of celiac disease: a meta-analysis. Frontiers in Endocrinology, 14, 1200372. DOI: 10.3389/fendo.2023.1200372.