When your body works against itself

What is Hashimoto's thyroiditis?

Hashimoto's thyroiditis, also called autoimmune thyroiditis, is an autoimmune disease of the thyroid gland. The immune system mistakenly targets the body's own glandular tissue, producing specific antibodies that can damage the thyroid. A distinction is made between cases in which patients show symptoms and those in which autoantibodies are present without impaired thyroid function.

The immune reaction leads to inflammation of the tissue, inhibiting the production of important hormones that regulate metabolism. Because the thyroid works closely with the hypothalamus and pituitary gland, damage to the tissue also affects the hormonal feedback loop responsible for hormonal balance. For this reason, Hashimoto's is one of the most common causes of hypothyroidism.

What types of Hashimoto's are there?

There are two main courses of Hashimoto's thyroiditis. In the atrophic form, the thyroid shrinks as tissue is progressively destroyed. In contrast, the thyroid enlarges in the hypertrophic form, for example to compensate for an iodine deficiency. Tissue damage can ultimately lead to reduced thyroid function in both forms.

Symptoms: how does Hashimoto's thyroiditis present?

Hashimoto's thyroiditis can present with a wide range of symptoms, which vary depending on the course of the disease. Initially, the thyroid inflammation often remains unnoticed because hormone secretion is still adequate. In the hypertrophic form, an enlarged thyroid or goitre may occur, sometimes causing difficulty swallowing or a feeling of tightness in the neck.

In some cases, a temporary overactive thyroid (hyperthyroidism) occurs. This is characterised by symptoms such as nervousness, palpitations, sweating, hair loss and weight loss, even though appetite is normal or increased.

As the disease progresses, the thyroid may no longer be able to maintain its function, resulting in underactive thyroid (hypothyroidism). This is associated with typical signs such as pronounced fatigue, sensitivity to cold, weight gain and reduced concentration. Symptoms like dry skin, hair loss, constipation and depressive moods may also occur.

Cognitive and emotional impairments, including memory problems and mood swings, are common. Occasionally, neurological symptoms such as tingling and numbness appear. Because these symptoms are so varied, diagnosis is often delayed.

What causes Hashimoto's thyroiditis?

Hashimoto's thyroiditis is caused by a misdirected immune response. Immune cells attack and destroy thyroid cells. Although the thyroid is affected, it is a disease of the immune system whose exact causes are not yet fully understood.

Genetic predisposition plays a significant role, as the disease runs in families and is often seen together with other autoimmune conditions such as type 1 diabetes or celiac disease. It is also suspected that a high iodine intake – for example through an iodine-rich diet or contrast agents used in medical imaging – may promote disease development in predisposed individuals.

In addition, hormonal changes during periods such as puberty or menopause, infections, and psychological stress may act as triggers. The consumption of nicotine and alcohol is also discussed as a possible risk factor. It is believed that the interplay of genetic disposition and external triggers ultimately activates immune cells, which then produce antibodies against the thyroid and cause inflammation.

The higher prevalence in women may be linked to the influence of sex hormones. Oestrogens are thought to promote the condition, while testosterone may have a protective effect.

How serious is Hashimoto's thyroiditis?

Untreated Hashimoto's thyroiditis can have serious health consequences, especially if it leads to hypothyroidism. Such hypothyroidism increases the risk of cardiovascular disease and, in severe cases, can lead to neurological complications such as seizures and altered consciousness. The development of thyroid cancer has also been associated with inadequately treated autoimmune thyroiditis. 

The situation is particularly critical during pregnancy: if hypothyroidism is not adequately corrected, the risk of miscarriage or preterm birth increases. Long-term developmental problems in the child may also occur. In addition to treating thyroid function, it is important to monitor for associated autoimmune conditions.

How is Hashimoto's thyroiditis diagnosed?

To diagnose Hashimoto's thyroiditis, the physician initially performs a physical examination. The neck is palpated to assess size, tenderness and the presence of nodules in the thyroid. Complementary ultrasound imaging can be used to visualise tissue changes, particularly if nodules are palpable or irregularities are suspected. Both size changes and characteristic patterns can be detected, varying by disease stage.

A key part of the diagnostic work-up are laboratory tests measuring thyroid hormones thyroxine (T4) and triiodothyronine (T3) as well as the stimulating hormone TSH in the blood. This allows assessment of thyroid function. At the same time, the presence of specific autoantibodies, especially against the enzyme thyroid peroxidase (TPO) and thyroglobulin, is investigated. Elevated levels of these autoantibodies are an important indication of an autoimmune disease. 

Because hormone levels can change over time, multiple blood tests are often required. Additional tests may be performed to exclude or confirm accompanying autoimmune diseases. A reliable diagnosis generally requires medical evaluation, as self-tests are not sufficient.

What a suitable diet for Hashimoto's can look like: practical tips

• Since Hashimoto's is associated with chronic inflammation of the thyroid, an anti-inflammatory diet is recommended. Prefer foods such as fish, nuts, seeds and high-quality vegetable oils like olive or rapeseed oil, as they provide healthy fatty acids that can help reduce inflammation.
• Also avoid frequent consumption of fatty meats, processed meats and high-fat eggs, as their arachidonic acid content can increase the production of inflammatory substances in the body and negatively affect the disease course.
• Sugar and refined carbohydrates, for example white bread and baked goods made with white flour, should be consumed only in moderation. They cause blood sugar fluctuations that promote inflammation and can worsen symptoms.
• Try to avoid products containing hydrogenated vegetable oils and trans fats whenever possible. These are found mainly in convenience foods, crisps and certain baked goods and are associated with increased chronic inflammation.
• Reduce consumption of gluten-containing cereals if you are sensitive. Gluten-free alternatives include pseudo-cereals like buckwheat, amaranth and quinoa, as well as millet and rice, which do not further fuel inflammatory processes.
• Also include plenty of foods rich in omega-3 fatty acids in your diet. These polyunsaturated fatty acids have anti-inflammatory effects and are found, for example, in oily fish such as salmon, as well as in walnuts, flaxseeds and hemp seeds.
• Ensure a daily supply of natural sources of anti-inflammatory vitamins such as vitamin C from bell peppers, Brussels sprouts or citrus fruits, vitamin E from nuts or seeds, and beta-carotene from carrots, pumpkin or tomatoes. This helps reduce oxidative stress in your body.
• Use the power of phytochemicals to strengthen your immune defences and reduce inflammation. Flavonoids are found in berries, apples and onions, glucosinolates in cabbage and radishes, and curcumin in turmeric. Curcumin is particularly effective when combined with black pepper.
• High-fibre foods such as oats, legumes, flaxseeds and psyllium help by producing butyric acid in the gut, which can lower pH and thus counteract inflammation and oxidative stress.
• Be cautious with iodine. An adequate intake via iodised salt, dairy products or eggs is important. Highly iodine-rich foods such as certain seaweeds or iodine supplements should only be consumed after consultation with your doctor.
• Selenium is an essential nutrient that supports thyroid function and has antioxidant properties. You can find selenium mainly in Brazil nuts, fish and eggs. Just one to two Brazil nuts a day can cover the requirement well.
• If you have concomitant autoimmune gastritis, avoid very spicy, fatty or heavily seasoned foods as well as coffee and smoked products. A glass of lemon water before meals can aid digestion.
• Consistently avoid alcohol and tobacco, as these substances promote inflammation and can impair thyroid function. 

Hashimoto's thyroiditis often requires considerable patience, but with targeted treatment and a conscious lifestyle, symptoms can be alleviated and well-being improved.