Persistent fatigue, weight gain, mood swings… When the thyroid functions poorly, many look for solutions in terms of diet, sometimes by following “special” diets found on the Internet. But what do scientific studies really say?
A large analysis published in 2026 in a journal specializing in endocrinology reviewed twenty years of research on the link between diet and thyroid health. Objective: to check whether these restrictive diets (gluten-free, lactose-free, soy-free, etc.) are of real benefit.
Main conclusion: yes, diet plays a role. But no, extreme diets are not the miracle solution. The dietary model that emerges the most favorable is well known: the Mediterranean diet.
What science says about diet and thyroid
The researchers first point out an essential point: iodine is essential for the proper functioning of the thyroid, because it makes it possible to produce thyroid hormones.
But be careful, it’s all a question of balance. The contributions follow what is called a “U-shaped curve”:
- Not enough iodine: risk of goiter, nodules or hypothyroidism;
- Too much iodine: May trigger hyperthyroidism or an autoimmune disease in some people.
The recommended intakes are approximately:
- 150 mcg per day for an adult;
- 250 mcg during pregnancy and breastfeeding.
Other nutrients also play a key role:
- Selenium, iron and zinc help activate thyroid hormones;
- Vitamins D and B12 are often low in people with autoimmune diseases.
But important point: taking food supplements is only useful if a deficiency is confirmed. Otherwise, the benefit is not proven, and it may even be useless or even risky.
The Mediterranean diet, an ally for the thyroid
Among all the dietary models studied, one clearly stands out: the Mediterranean diet.
It is based on:
- Lots of fruits and vegetables;
- Whole grains;
- Fish;
- Olive oil;
- Few processed products.
According to researchers, this type of diet is associated with:
- Less inflammation in the body;
- Fewer antibodies attacking the thyroid;
- Better hormonal indicators.
Conversely, a so-called “Western” diet (rich in industrial products, sugars and saturated fats) promotes chronic inflammation and imbalances in the immune system.
A small study carried out in patients with Hashimoto’s thyroiditis goes in the same direction: after three months of a diet close to the Mediterranean model (with the addition of avoiding gluten), the participants showed:
- An improvement in their thyroid hormones;
- A drop in antibodies;
- Weight loss.
But be careful: this study involves a few people and over a short period of time. It is therefore impossible to draw definitive conclusions.
Should we eliminate gluten, lactose or soy?
This is a common question. The researchers’ answer is clear: among people who are not intolerant, these exclusions are not justified.
Very restrictive diets can even cause problems by causing nutritional deficiencies.
Another misconception: certain foods are “bad” for the thyroid, such as:
- Soy.
- Cabbage, broccoli and other cruciferous vegetables.
In reality, consumed in normal quantities, they do not pose a problem if the iodine intake is sufficient.
In practice: what to remember?
No need to change your diet or follow drastic diets. The recommendations are simple:
- Favor a varied and balanced diet.
- Take inspiration from the Mediterranean diet.
- Avoid ultra-processed products.
- Only take food supplements on medical advice.
And above all, remember an essential point: diet does not replace medical treatment of the thyroid. It can accompany it, but not replace it.
In summary, rather than looking for radical solutions, it is better to return to solid… and lasting foundations.