How to eat more iodine
Iodine is an essential mineral for a healthy functioning and is in every cell of the body. It is critical in the development of the fetus and in infants and impacts health throughout all life stages. The thyroid produces hormones using iodine and these hormones control our metabolism rate, cell development and repair, energy production. Iodine is used throughout the body in the muscles, inside the skin, salivary glands, ovaries, breasts, prostate, stomach, for bone and brain development. Our focus is on how to prevent iodine deficiency.
Where does iodine come from?
The mineral iodine is found in soil and in the ocean. The ocean provides us with iodine rich foods in the form of sea vegetables, fish and crustaceans which are the richest naturally occurring sources of iodine. Soils closer to the ocean are likely to contain more iodine with levels decreasing as you move further from the coastal regions. Unlike nutrients such as vitamins, calcium and iron, iodine does not naturally occur in specific foods. Rather it is present in soil and taken up through plants grown in that soil. Food grown in iodine deficient regions cannot provide the daily requirements of iodine. Iodine deficiency usually occurs when there is a lack of iodine within the soil (1). The predicament, therefore, cannot be eliminated by eating specific foods that are grown in the same region.
How to eat more iodine rich fruits and vegetables
To assist in the management of iodine levels there is a range of iodine rich foods that can be included in your diet. Including foods high in iodine to avoid hyperthyroidism is a great idea. Due to reasons of varying iodine levels in soils, iodine levels in foods also vary and can only be used as a guide. The ocean provides our best sources of iodine rich foods.
Sea Vegetables provide iodine rich foods and yet we often don’t know how to utilize these in our daily diets. Cooking seaweed also effects the iodine levels. Variations also occur due to confusion around wet and dry weights which can result in over estimations of iodine levels (2).
Kelp, just a tablespoon, provides up to 6000 % of the recommended daily intake (RDI) of iodine. Seaweed is also a good source of vitamin K, iron and very high concentrations of calcium. Iodine levels in foods vary, depending in which oceans they grow. Nori -1 gram has approximately 16-43mcg of iodine, 11-29% RDI. Wakame – 1gram averaged from around the world 66mcg of iodine, 44% RDI. Kombu –1gram has up to 2984mcg of iodine, over 2,000% RDI (3)
Scallops provide 135mcg in a 4-ounce serving or 90% of the RDI. In addition, they are an excellent source of B12 and phosphorous and a good source of protein, choline, selenium, magnesium, zinc and potassium.
Cod fish is as healthy as it is delicious and a natural source of iodine. Not only is it low in calories and fat, it is also iodine-rich. One 3 ounce serving contains between 63-99mcg, 42 – 66% of the RDI. (4) (5) Cod provides a variety of other nutrients including vitamin B12, B6, calcium, selenium, potassium, phosphorous, magnesium and Omega-3 fatty acids. Cod is also high in protein.
Shrimp is packed with iodine. A 3 ounce serving contains 35mcg, 25% of the RDI. This serving will provide close to 100% of your daily selenium needs. Shrimp is also a great source of vitamin B12, phosphorous, choline, copper and zinc.
Cranberries can supply 100% of the RDI of iodine in just one serve. About 3 ounces can supply approximately 300 mcg of iodine. This tiny tart fruit is well known for its anti- inflammatory and anti-carcinogenic antioxidants. Along with vitamins C, E and K.
Tuna a single 3 ounce serving of tuna (canned) you will get around 17 mcg of iodine, 11% RDI. Tuna provides excellent source of selenium, vitamin B3, B6, B12 and protein. It is also a good source of B2, D choline potassium and magnesium.
Organic yogurt – one cup contains 75mcg of iodine, 50% of a healthy adult’s daily iodine requirements. In yogurt you have a good source of vitamin B12, zinc, potassium, riboflavin, calcium and phosphorous.
Baked potatoes, with the skin on, will provide about 60mcg, 40% of the DRI. Potatoes also contain vitamins and minerals, magnesium, copper, potassium, B6, Vitamin C. Potatoes contain substantial amounts of fiber and folate.
Milk, with a single cup contains 56mcg, 37% of the RDI. Milk will also provide potassium, phosphorus, calcium, protein, and vitamins B2and B12
Navy beans possibly top the list in the bean family for iodine levels with half a cup containing approximately 32mcg, 21% of RDI. They are also a good source of folate, manganese and vitamin B1.
Iodine in Eggs, especially when hard boiled, is a good source. One hard boiled egg contains around 24 mcg of iodine. 16% RDI. Great as a protein source the humble egg provides vitamin D, B6 and B12, iron, selenium, lutein and zeaxanthin and carotenoids.
Dried prunes 5 dried prunes will give you 13 mcg of iodine and about 9% DRI. This unassuming wrinkled fruit is a rich source of fiber, vitamins and minerals, including vitamin K, beta-carotene, potassium, retinal and iron.
Cheese – raw cheddar is another iodine rich food. An ounce contains up to 12 mcg of iodine 8% of RDI. Raw cheddar also contains calcium and sodium.
Some other iodine rich foods that are less concentrated include Lima beans, apple juice, green peas and bananas. Foods like beef, pinto beans and chicken also contain iodine but only in small quantities. (6)
Recommended daily intake.
Since the body does not produce its own iodine, the only way to introduce it into your system is through diet or supplementation. WHO and UNICEF recommend the following:
0 to 7 years 90 micrograms or millionths of a gram
7 to 12 years 120 micrograms
12 years plus 150 micrograms (for male and female)
Pregnant women 250 micrograms
Lactating women 290 micrograms
What are the effects of iodine deficiency?
If we do not have sufficient iodine in our bodies the effects are seen throughout the body. A short list of some effects, that can be seen are:
- can’t make saliva – a dry mouth
- dry eyes
- inability to sweat
- dry skin
- lowered alertness
- unexpected weight gain
- cold hands and feet
- and so on
What about an excess of iodine?
Excessive consumption of iodine can both worsen and cause hypothyroidism and hyperthyroidism (1). An excess can cause some of the same symptoms as too little iodine such as goiter. High levels can also cause inflammation of the thyroid gland. Common side effects include stomach pain, feeling ill, headache, runny nose metallic taste, and diarrhea.
Why is iodine deficiency a problem?
It is believed that the iodine intake has dropped in recent years, with continued research looking at the issue. Some reasons could be;
- Less iodized salt used in cooking and at the table
- Food manufacturers using non-iodized salt
- Milk has less iodine due to changes in substances used in its treatment
- Possible reduction of iodine in soils
- Changes in dietary patterns such as those who don’t consume dairy and fish.
- Common foods which contain thiocyanates in high amounts can interfere with the thyroid gland. Some foods which contain thiocyanates are the brassica vegetables, and soy.
Another consideration in iodine deficiency is to reduce interference from halogens (fluorine, chlorine bromine and astatine) which block the absorption of iodine in the body.
- Try to eat organic whenever possible and wash your fruit and vegetables carefully to lesson insecticide exposure.
- Drink filtered water and avoid sodas
- Replace personal care and household cleaning products with nontoxic products
- Replace plastic containers for food and water storage with glass and ceramic containers
Iodine is vital to health whether as an unborn child or an elderly person, yet sadly many people do not have this knowledge or just assume they are getting the nutrients they need without watching their intake. As always, be cautious of using and eating too much of these foods as elevated iodine levels can cause serious problems with your health.
Iodine deficiency can be controlled by including iodine rich foods in the diet and taking good quality iodine supplements.