Natural Sources of Iodine
Iodine is a trace element that cannot be synthesised by the body. Due to this it is necessary to obtain the bodies iodine requirements from dietary sources.
Unfortunately though Iodine is not present in many foods and the ones that it is present in tend not to have the levels verified. Hence it is virtually impossible to know how much iodine you are consuming in your diet. The below table shows you the foods that are considered to have the most iodine present in them, the only glaring omission is seaweed - that is by far the best natural source of Iodine.
Please note the below amounts are only indicative and can very greatly. This is because the amount of Iodine in soils will vary greatly depending on location and fertilisers being used. Iodine is believed to be getting further depleted from much of the soil and this has a direct effect on the amount of Iodine in the plants being grown.
Natural Food Sources of Iodine
Food |
Portion |
Average iodine/ portion (mcg) |
Cow’s milk |
200ml |
50-80** |
Organic cow’s milk |
200ml |
30-65** |
Yoghurt |
150g |
50-100** |
Eggs |
1 egg (50g) |
20 |
Cheese |
40g |
15 |
White fish |
100g |
115 |
Oily fish |
100g |
50 |
Shellfish |
100g |
90 |
Meat |
100g |
10 |
Poultry |
100g |
10 |
Nuts |
25g |
5 |
Bread |
1 slice (36g) |
5 |
Fruit and veg |
1 portion (80g) |
3 |
**Depending on the season, higher value in winter. These amounts will vary greatly and are meant as indicative.
The above table highlights that it is difficult to get sufficient Iodine into the diet, especially for Vegans! Luckily though seaweed is by far the best natural source of Iodine. Many dietary associations and bodies recommend not consuming seaweed as the levels of Iodine can be so concentrated that it can cause an adverse reaction in people who are not used to consuming high amounts.
Most seaweed products only show the Typical Nutritional Profile of the seaweed in question and not the quantities in each individual batch. To highlight the differences in Iodine levels of different seaweeds, please view the below table.
As mentioned the levels of iodine present will vary but it is a good indicator of how different the iodine levels are depending on seaweed variety.
Seaweed Name | Iodine Levels (ppm) |
Dulse | 150 - 550 |
Sea Spaghetti | 185 |
Nori | 150 - 550 |
Laminaria Digitata | 800 - 5000 |
Alaria | 165 |
Irish Moss | 200 - 300 |
Sea Lettuce | 240 |
Sea Grass | 780 |
Bladderwrack | 500 |
Sugar Kelp | 5000 |
Sargassum | 30 |
Ascophyllum | 700 - 1200 |
- Timothy Kinghan