We all know that a healthy, balanced diet should include vitamins and macronutrients, such as proteins and carbohydrates. What's sometimes overlooked are essential minerals, which play a fundamental role in maintaining the body's balance. This is the case with iodine—a micronutrient essential for proper thyroid function, and a deficiency in which can have serious consequences. Let's explore its importance in depth, understand what iodine is for, identify the main signs of deficiency, and introduce you to the best dietary sources.

What is the role of iodine in the body?

Iodine is essential for the synthesis of thyroid hormones—specifically thyroxine (T4) and triiodothyronine (T3)—produced by the thyroid . ¹ These hormones regulate basal metabolism, that is, how our body produces and uses energy. They are also essential for growth, cognitive development (especially in early life), heart function, body temperature regulation, and even mood.

By ensuring proper thyroid and metabolic function, iodine also plays an indirect antioxidant role: it contributes to a more balanced cellular environment, helping to reduce oxidative stress and protect cells against premature aging and damage caused by free radicals — ^unstable molecules that can accelerate degenerative processes and increase the risk of chronic diseases.

Signs and risks of iodine deficiency

When the body doesn't receive enough iodine, imbalances arise with significant health impacts. Iodine deficiency can manifest in a variety of ways, and one of the most common symptoms is goiter ^. — a visible increase in the thyroid in the neck region, which results from the gland's effort to compensate for the lack of this mineral.

Other common signs include persistent fatigue, feeling cold even in warm environments, difficulty concentrating, mood swings (including irritability and depression), hair loss, and dry skin . ³ In prolonged cases, iodine deficiency can also translate into metabolic problems, leading to unexplained weight gain and a general feeling of physical and mental sluggishness, accompanied by memory difficulties . ⁴

Risk Phases

At some critical stages of life, iodine deficiency can have particularly serious implications, which is why it requires extra attention:

- During pregnancy and breastfeeding , iodine deficiency can compromise the neurological development and nervous system of the fetus, with lasting impacts on the child's health ⁴ ;

- In childhood , it can result in growth retardation and learning and concentration difficulties, affecting school performance and general well-being ⁴ ;

- In old age , when there is a greater risk of thyroid dysfunction, it may be indirectly associated with cardiovascular and metabolic diseases ⁵ .

Food sources of iodine

Ensuring adequate iodine intake isn't complicated, and in most cases, a varied and balanced diet is sufficient. The most important dietary sources include ⁶ :

• Iodized salt , the most common source, especially in countries with iodine-poor soil, should be used in moderation, as excessive salt consumption can have other negative effects, such as increased blood pressure;

• Fish and shellfish , especially mussels, clams, cod, sea bream, snapper, shrimp and horse mackerel, which also provide other important nutrients such as omega-3 ;

• Seaweed , such as nori, wakame or kombu (which require moderation, due to their high iodine content);

• Dairy products (particularly low-fat Flemish cheese) and eggs (especially yolks) . Although iodine is present in smaller quantities, and always dependent on the animal's diet, they are significant for daily consumption;

From this list, it's easy to adopt some simple strategies to ensure adequate iodine intake—from moderate use of iodized salt to regular consumption of fish and eggs (one or two per week is enough), to the occasional addition of seaweed to your diet. Seaweed can be added to salads or soups and is a good opportunity to experiment with influences from cuisines like Japanese, where it's highly valued.

As a general rule, it's always worth prioritizing fresh, minimally processed foods: many processed foods contain high amounts of sodium, but don't use iodized salt in their composition, which means they increase the salt content in the diet without contributing to iodine intake.

Recommended doses of iodine

The recommended daily intake of iodine is about 150 micrograms for healthy adults . ⁷ During pregnancy and breastfeeding, these needs increase to 200 micrograms per day . ⁷ These are small amounts that are easy to achieve with a varied diet.

There are, however, situations that require special attention. Very restrictive diets (such as a poorly planned vegan diet), intestinal absorption problems, high exposure to pollutants, or excessive alcohol and tobacco consumption can compromise ^iodine availability . Aging and intense physical exercise also increase the need for antioxidants .

In these cases, supplementation can be an effective response, but always under the guidance of a health professional, since excess iodine can cause unwanted effects such as nausea, headaches, metallic taste in the mouth, changes in thyroid function and coagulation problems.

Conclusion

Iodine is a mineral that's easy to underestimate, but essential for the body's balance: it's directly involved in hormone production, metabolic regulation, cognitive development, and even cellular defense.

While adequate iodine intake is, in most cases, easily achieved through a balanced diet, it's crucial to be alert to signs of deficiency—especially when risk factors are present—and consider supplementation as a valid option, always under professional supervision. Ensuring adequate iodine levels is a long-term investment in health, contributing to a more balanced, resilient body with the energy to face everyday challenges.

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