Iodine in foods: The best dietary sources to know

Why is iodine important for the body?

Iodine is a micronutrient that the body needs in very small amounts, but its role is crucial. It contributes to:

• normal production of thyroid hormones and normal thyroid function;
• normal cognitive function and normal functioning of the nervous system;
• normal energy metabolism;
• the maintenance of normal skin.

Even though iodine requirements are low, a sufficient daily intake remains essential to ensure the body has the necessary amount for these various functions to operate correctly.

Why eat iodine-rich foods?

Diet is the primary way to naturally provide the body with iodine. Unlike some nutrients that the body can store in large quantities, iodine must be supplied regularly through dietary habits.

That's why it's essential to adopt a varied and balanced diet, including different dietary sources of iodine to help maintain sufficient daily intake. A diet poor in iodine-rich foods can limit intake, especially for some people with specific dietary habits or an undiversified diet.

What foods are rich in iodine?

Iodine-rich foods are an important source for contributing to the daily intake of this essential trace element. However, not all foods contain the same amount of iodine. Their content can vary depending on several factors, such as the origin of the products, their production environment, farming conditions, or the techniques used during their processing.

It is therefore interesting to know the main categories of foods that can naturally contribute to iodine intake and to incorporate them into a varied and balanced diet.

Seafood: the main dietary sources of iodine

Foods from the marine environment are among the most interesting natural sources of iodine.

This is simply explained: iodine is naturally present in the oceans. Marine organisms can therefore accumulate it in their tissues.

1. Iodine-rich fish

Certain saltwater fish can contribute significantly to iodine intake, notably:

• cod;
• pollock;
• saithe;
• certain white fish.

These foods also have other nutritional benefits:

• rich in quality protein;
• source of vitamins and minerals;
• presence of interesting fatty acids depending on the species.

In a balanced diet, regularly incorporating fish can therefore be an interesting strategy to diversify micronutrient sources.

2. Seafood: a natural source of iodine

Seafood also contains natural iodine.

Notably, this includes:

• mussels;
• shrimp;
• crustaceans.

Beyond their iodine content, they also provide protein and various minerals.

However, as with all foods, their benefit depends on the overall balance of the diet. No single food can meet all nutritional needs.

Seaweed: foods particularly concentrated in iodine

Seaweeds are among the most naturally iodine-rich foods. As they grow in a marine environment, they can accumulate this trace element in significant quantities. However, their iodine content varies greatly depending on the species, their origin, and harvesting conditions.

Among edible seaweeds that naturally contain iodine, we find notably:

• Kelp: a group of brown seaweeds belonging notably to the Laminaria and Saccharina genera. Widely used in Asian cuisine and as dietary supplements, kelp is particularly known for its high iodine concentration. However, its consumption must remain moderate, as some varieties can provide very large amounts of iodine;

• Kombu (or konbu): a brown seaweed widely used in Japanese cuisine, particularly known for its high iodine concentration;
  
  
• Wakame: a brown seaweed frequently consumed in Asian soups and salads;
  
  
• Nori: a red seaweed used notably to prepare the seaweed sheets wrapped around sushi;
  
  
• Dulse: a red seaweed consumed dried or as a condiment;
  
  
• Sea lettuce (ulva): a green seaweed appreciated for its richness in minerals;
  
  
• Himanthalia elongata (sea spaghetti): a brown seaweed consumed as a side dish or culinary ingredient.

However, this richness in iodine requires some vigilance. Certain seaweeds, especially brown seaweeds like kombu, can contain very high amounts of iodine. Excessive consumption may not be suitable for all people, particularly those with a particular sensitivity to thyroid function.

Seaweeds can therefore perfectly find their place in a balanced diet, but they must be consumed reasonably and diversely. The goal is not to seek a maximum iodine intake, but rather to maintain adequate intake through a varied diet including different sources of iodine.

Dairy products: a daily source of iodine

Dairy products can also contribute to dietary iodine intake.

This includes notably:

• milk;
• yogurt;
• certain cheeses.

Their contribution depends on dietary habits and quantities consumed.

In several countries, dairy products represent a significant source of iodine in the everyday diet, notably due to farming and animal feeding practices.

They can therefore complement other food sources such as fish or seafood.

Eggs: an interesting food to supplement intake

Eggs are also among the foods that can provide iodine.

They have the advantage of being easy to incorporate into many meals:

• breakfast;
• lunch;
• dinner;
• snacks as needed.

They also provide:

• complete proteins;
• vitamins;
• several minerals.

In a diet suitable for bodybuilders or fitness enthusiasts, eggs can therefore naturally find their place alongside other nutrient-rich food sources.

How much iodine should be consumed daily?

Iodine requirements vary depending on age, sex, and certain specific periods of life.

According to the nutritional recommendations published by the French Agency for Food, Environmental and Occupational Health & Safety (ANSES) in its document "Nutritional references for vitamins and minerals" (2025), recommended iodine intakes are established to meet the needs of the majority of the population (2).

For adults aged 18 and over, both men and women, the adequate intake is set at 150 µg of iodine per day.

However, these needs can be higher in certain specific situations, notably during pregnancy and breastfeeding.

How to incorporate more iodine into your diet?

Adopting an iodine-rich diet does not necessarily mean completely changing one's habits. A few simple strategies can help:

Vary protein sources

Instead of consuming only meat or plant-based proteins, it may be interesting to also include:

• fish;
• seafood;
• eggs.

This diversification naturally increases the intake of different micronutrients.

Eat fish regularly

Fish can be easily integrated into a balanced diet:

Meal examples:

• cod fillet with vegetables and starchy foods;
• white fish with brown rice;
• mixed salad with seafood.

The goal is not to eat fish at every meal, but to vary food sources.

Use iodized salt when it matches dietary habits

In some countries, iodized salt also contributes to dietary iodine intake.

However, it should be noted that excessive salt consumption is still not recommended.

The choice of iodized salt should therefore not be an invitation to increase salt consumption, but rather one possibility among existing dietary strategies.

Are iodine-based dietary supplements necessary?

For a person with a varied and adapted diet, supplementation is generally not necessary.

Iodine-based dietary supplements, usually available in capsule or tablet form, can be a practical solution for some people with insufficient dietary intake.

They can be particularly useful for people with an undiversified diet, certain athletes following a highly structured meal plan, or vegetarians who consume few naturally iodine-rich foods.

However, a varied and balanced diet remains the best source of iodine. Supplementation should not replace good eating habits and should be considered with caution.

Before starting an iodine-based dietary supplement, it is recommended to seek advice from a healthcare professional, especially in case of thyroid problems, medical treatment, or specific situations such as pregnancy.

Iodine foods, the best dietary sources to know: In summary

Foods containing iodine are an important topic when seeking to understand how to build a balanced and nutrient-rich diet.

Iodine is an essential micronutrient involved notably in the production of thyroid hormones.

The main dietary sources of iodine are:

• saltwater fish;
• seafood;
• certain seaweeds;
• dairy products;
• eggs.

For most people, the best approach remains simple: adopt a diversified, balanced diet adapted to individual needs.

Finally, before considering iodine supplementation, it is best to seek advice from a healthcare professional to tailor intake to one's personal situation.