Iodine is an essential mineral that you should obtain from your diet.
Interestingly, your thyroid gland needs it to produce thyroid hormones, which have many important responsibilities in your body (1, 2).
The recommended daily intake (RDI) of iodine is 150 mcg per day for most adults. For pregnant or lactating women, the requirements are higher (3).
In fact, a third of the population is at risk of deficiency, especially those who live in areas that have only a small amount of iodine in the soil, including European countries (1).
Iodine deficiency can cause inflammation of the thyroid gland, known as a goiter, and hypothyroidism, which can cause fatigue, muscle weakness and weight gain (1, 2, 4).
This article explores 9 food sources rich in iodine that can help prevent a deficiency.
Seaweed is a good source of antioxidants, vitamins and minerals. It is also low in calories.
Seaweed is one of the best natural sources of iodine. However, the amount can vary significantly depending on the type of seaweed, the region in which it grew and its preparation (5).
Three popular varieties of seaweed include kombu kelp, wakame and nori.
Kombu is a brown seaweed that is sold dry or in fine powder. It is often used to make a Japanese soup called dashi.
In a study that examined samples of seaweed from several Asian countries for its iodine content, it was found that kombu kelp contains by far the largest amount of iodine compared to other species of algae (5).
The kombu kelp can contain up to 2,984 mcg of iodine per sheet of seaweed (1 gram). This provides almost 2,000% of the recommended daily intake (6).
Excessive iodine consumption is well tolerated in most people, but can cause thyroid dysfunction in susceptible people (7).
Wakame is another type of brown seaweed that has a slightly sweet flavor. It is commonly used to make miso soup.
The amount of iodine in wakame kelp depends on where it is grown. Wakame from Asia has higher amounts of iodine than wakame from Australia and New Zealand (8).
One study found that the average amount of iodine in wakame seaweed from different parts of the world was 66 mcg per gram, or 44% of the recommended daily intake (8).
Nori is a type of red seaweed. Unlike brown seaweed, it has a much lower iodine content.
Nori is the type of seaweed that is commonly used in sushi rolls.
The content of iodine in nori varies between 16 and 43 mcg per gram, or approximately between 11 and 29% of the daily value (8, 9).
Summary Seaweed is an excellent source of iodine. However, the amount it contains depends on the species. Kombu kelp offers the highest amount of iodine, with some varieties containing almost 2,000% of the daily value in one gram.
Cod is a versatile white fish with a delicate texture and a mild flavor.
It is relatively low in fat and calories, but offers a wide variety of minerals and nutrients, including iodine (6).
According to the Icelandic Food Content Database, low-fat fish have the highest amounts of iodine (10).
For example, 3 ounces (85 grams) of cod have approximately 63-99 mcg, or 42-66% of the recommended daily amount (6, 10).
The amount of iodine in cod may vary slightly depending on whether the fish was raised on the farm or caught in the wild, as well as the region where the fish was caught (10, 11).
Summary Higher amounts of iodine are found in low-fat fish compared to fatty fish. For example, a lean fish such as cod can provide up to 66% of the daily value.
Dairy products are important sources of iodine, especially in American diets (12).
The amount of iodine in milk and milk products differs greatly depending on the iodine content in livestock feed and the use of iodine-containing disinfectants during milking (13).
A comprehensive study measured iodine content in 18 different brands of milk sold in the Boston area. He discovered that the 18 brands had at least 88 mcg in 1 cup (8 ounces) of milk. Some brands even contained up to 168 mcg in a cup (14).
Based on these results, 1 cup of milk can provide 59-112% of the recommended daily amount of iodine.
Yogurt is also a good source of iodine from dairy products. One cup of plain yogurt provides about half the recommended daily amount (6).
The amount of iodine in the cheese varies according to the type.
Cottage cheese is one of the best sources of iodine. One cup of cottage cheese provides 65 mcg, while an ounce of cheddar cheese provides approximately 12 mcg (15).
Summary Although the exact amount of iodine in milk products varies, milk, yogurt, and cheese are important sources of this in the American diet.
4. Iodized Salt
Currently, both iodized and undeclared salt are sold in the United States.
The addition of iodine to table salt began in the USA. UU In the early 1920s to help decrease the appearance of goiters or swelling of the thyroid gland (16).
There is approximately 71 mcg of iodine in 1/4 teaspoon of iodized salt, which is 47% of the recommended daily intake. However, salt also contains sodium (6, 17).
In recent decades, the intake of iodine has decreased in the United States. This is probably due to the push of the main health organizations to restrict the daily intake of sodium to prevent or treat high blood pressure.
However, salt only seems to raise blood pressure in salt sensitive individuals, which is approximately 25% of the population (16, 18).
Summary Iodized and iodine-free salt is commonly sold in grocery stores. The consumption of 1/2 teaspoon of iodized salt per day provides enough iodine to prevent a deficiency.
Shrimp is a seafood rich in protein and low in calories that is a very good source of iodine (6).
In addition, shrimp provide key nutrients such as vitamin B12, selenium and phosphorus (19).
Shrimp and other shellfish are good sources of iodine because they absorb some of the iodine that is naturally present in seawater (12).
Three ounces of shrimp contain approximately 35 mcg of iodine, or 23% of the recommended daily intake (6).
Summary Shrimp is a good source of protein and many nutrients, including iodine. Three ounces of shrimp provide approximately 23% of the daily value.
Tuna is also a food rich in iodine, rich in calories and protein. In addition, it is a good source of potassium, iron and B vitamins (20).
Tuna is also a good source of omega-3 fatty acids, which can reduce your risk of heart disease (21).
Fish with higher fat content offer lower amounts of iodine. Since tuna is a fatter fish, the amount of iodine found in tuna is lower than in lean fish varieties, such as cod (22).
However, tuna remains a relatively good source of iodine, since three ounces provide 17 mcg, or approximately 11% of the recommended daily intake (6).
Summary Tuna offers less iodine than lean fish, but it is still a relatively good source. Three ounces of tuna provide approximately 11% of the recommended daily amount.
Eggs are also a good source of iodine.
For less than 100 calories, a whole egg provides a lean source of protein, healthy fats and a wide variety of vitamins and minerals (23).
However, most of these nutrients, including iodine, come from the yolk (24).
Egg yolks are a good source of iodine because it is added to chicken feed. However, as the iodine content in chicken feed may vary, the amount found in the eggs may also fluctuate (12, 24).
On average, a large egg contains 24 mcg of iodine, or 16% of the daily value (6, 24).
Summary Most of the iodine in the eggs is in the yolk. On average, a large egg provides 16% of the recommended daily amount.
Prunes are prunes that have dried up.
Plums are a good source of vegetarian or vegan iodine. Five dried plums provide 13 mcg of iodine, or approximately 9% of the daily value (6).
Prunes are commonly known to help relieve constipation. This is due to its high fiber content and sorbitol, a type of sugar alcohol (25).
Prunes are rich in vitamins and nutrients, such as vitamin K, vitamin A, potassium and iron (25).
Due to the nutrients that plums offer, they can help improve heart health, lower the risk of colon cancer and even help control weight by decreasing appetite (25, 26, 27).
Summary Prunes are full of vitamins and nutrients. Five dried plums provide a good vegetarian source of iodine by reaching 9% of the daily value.
9. Lima Beans
Lima beans are commonly associated with the popular succotash, which mixes Lima beans and corn.
Lima beans are a good source of fiber, magnesium and folic acid, which makes them a healthy choice for the heart (28).
They are also a relatively good source of iodine for vegetarians or vegans.
Due to the variation of iodine in the soil, irrigation water and fertilizers, the amount of iodine can vary in fruits and vegetables (6, 29).
However, on average, one cup of cooked beans contains 16 mcg of iodine, or 10% of the daily value (6).
Summary Lima beans are rich in fiber, magnesium, folic acid and iodine. A cup of cooked beans provides approximately 10% of the daily value of iodine.
The bottom line
Iodine is an important mineral, although few sources of food are rich in it.
This is why many people around the world run the risk of developing a deficiency.
The foods richest in iodine include seaweed, dairy, tuna, shrimp and eggs. In addition, most table salt has been iodized, which provides an easy way to add iodine to your meals.
The foods listed in this article are not only some of the best sources of iodine, but they are also very nutritious and easy to add to your daily routine.
Reference: https: //www.healthline.com/nutrition/iodine-rich-foods