Iodine: Properties, Nutrients & Side Effects

What is iodine?

Iodine is an essential trace element for the human body, which contributes to important processes in the body, such as the production of thyroid hormones and brain function.

However, it cannot be produced by our body and therefore, it must be obtained through food or in case of deficiency from nutritional supplements. In fact, it seems that a third of the world’s population is iodine deficient. [1] [2]

Properties

1. Iodine and thyroid

Iodine is important for the production of the thyroid hormones thyroxine and triiodothyronine. These play a role in protein formation and enzyme activity, as well as in regulating metabolism.

If there is not the necessary amount of iodine in the body, this can cause under- or over-functioning of the thyroid gland, causing negative effects. That is why in most developed countries salt is enriched with iodine (iodized salt).

What we pay attention to in nutrition and supplements?

It seems that there is no ideal diet for people with thyroid diseases as they are individual cases and we must take into account factors such as age, body weight, accompanying diseases and medical history. In hypothyroidism, there are insufficient studies to show that eating or avoiding certain foods will improve thyroid function. [4]

At the same time, exposure to high concentrations of iodine, in people with hypothyroidism, can lead to a reduced release of thyroid hormone, therefore it is recommended to avoid dietary supplements containing iodine. That is why nowadays many companies produce vitamins free of iodine eg. Full Health Nutrition Support, Nature’s PLus Just Vitamins.

In the general population, the American Thyroid Association recommends not consuming a daily iodine supplement or kelp containing more than 500 mcg of iodine. [5]

2. Neurodevelopment during pregnancy

Iodine intake during pregnancy is linked to brain development in fetuses and healthy brain function during childhood.

Therefore, a greater amount of iodine needs to be taken during pregnancy. The recommended daily intake in this case is 220 mcg, whereas in other adults the recommended daily intake is 150 mcg. 

Even during breastfeeding, the existence of iodine is essential, thus the recommended daily intake is 290 mcg, as it is transferred through breast milk to the nursing infant.

3. May help treat fibrocystic breast disease

It seems that iodine contributes to the treatment of fibrocystic breast disease. It is more common in women of reproductive age and can cause chest pain. But under no circumstances should we self-medicate unless recommended by our doctor.

4. Disinfectant water

Iodine is a way of water disinfection, which is particularly useful in travel conditions. A 2% tincture of liquid iodine can be added to water, 5 drops per quart of pure water. However, because there are concerns about increasing total iodine intake in humans, it should not exceed 2 mg of iodine per day.

6. Treatment of infections

Iodine can be used topically to prevent infections as it has the ability to destroy bacteria that may come from scratches or cuts. However, using iodine topically cannot be used on newborn babies, nor can it be used on deep cuts or bites from animals. [6]

Foods with iodine

Iodine is mainly found in foods of animal origin, seafood and vegetables, while, to a lesser extent, it is found in fortified foods such as bread, cereals and milk. Indicative [7]:

• Seaweed
• Iodized salt
• Low fat milk
• Greek yogurt
• Eggs
• Bread
• Liver

Which fish have iodine?

Seafood is an excellent choice of iodine. One serving of cod contains 158 mcg of iodine, whereas a serving of cooked oysters can provide the human body with up to 93 mcg of iodine.

Indicative and more detailed, the following table shows foods rich in iodine, including fish. [8]

Herbs with iodine

1. Kelp

Kelp (Bladderwrack/ Fucus vesiculosus) is a seaweed rich in iodine. It appears to contribute to the thyroid gland as a form of treatment in cases of hypothyroidism as iodine stimulates the production of thyroxine and increases the basal metabolic rate. However, excess iodine intake can lead to inhibition of iodine oxidation, a primary step in thyroid hormone biosynthesis. [9] [10]

2. Ashwagandha

Ashwagandha  (Withania somnifera) is traditionally used in Ayurveda and is a known immunomodulatory and anti-inflammatory ingredient. Studies report that it contributes to thyroid stimulation and also appears to affect thyroid function in people with bipolar disorder, according to recent research. [11] [12]

3. Bacopa 

This particular herb has a neuroprotective effect and is also used in Ayurvedic medicine. In addition to improving cognitive ability and dealing with lack of concentration, studies have recently shown that it helps with thyroid function. Bacopa (Bacopa monnieri) alcoholic extract appeared to contribute to the prevention of hypothyroidism by increasing the production of thyroid hormones. It offers a reduction in the appearance of lipids and also acts as an antioxidant. Finally, it appears to effectively regulate T3 and T4 function as well as neurodegenerative markers. [13] [14] [15]

4. Coleus 

Coleus (Coleus forskohlii) is a rich source of the labdanate diterpene forskolin, which contributes to thyroid function by stimulating lipolysis in fat cells. It increases the synthesis of T4 and the use of the herb appears to reduce TSH levels while, correspondingly, increasing the concentration of T3 and T4. [16] [17]

5. Black cumin seed

Black cumin seeds (Nigella sativa) are known for their antioxidant, anti-inflammatory and immunomodulatory properties. Recently, studies have shown that it works protectively in cases of hypothyroidism and especially in Hashimoto’s thyroiditis. Thymoquinone, a component of black cumin seed, appears to improve thyroid status. [18] [19]

6. Bugleweed

Bugleweed  (Lycopus spp.) is an herb that has long been used in folk medicine and studies have reported that it inhibits the effects of TSH as well as thyroid-stimulating IgG antibodies, which ultimately results in decreased thyroid secretion. [20]

7. Spirulina

   People who have problems related to the thyroid such as hypo- or hyperthyroidism, Hashimoto’s thyroid or even thyroid nodules are recommended to avoid spirulina, because it contains iodine, although there are not enough studies showing the association of spirulina with thyroid. However, there is now a wide variety of dietary supplements with this ingredient that state that they are on the market without iodine. [21]

Signs of deficiency

Iodine deficiency can cause cognitive damage – since it helps cells to function and grow – and needs special attention especially in infants, pregnant women and breastfeeding women.

 In adults, iodine deficiency can cause insufficient production of thyroid hormones, the well-known hypothyroidism, disrupting metabolic functions. Typical signs of iodine deficiency are:

• Fatigue
• Weakness
• Sensitivity to cold
• Constipation
• Dry skin and hair
• Weight gain
• Swelling of the thyroid glands in the neck
• Goitre in the throat
• Hair thinning
• Dry skin
• More intense feeling of cold
• Slowing of heart rate
• Learning and memory difficulties
•  Expanded language
• Swollen face
• Constipation
• Poor muscle tone
• Need for more frequent sleep

People at increased risk of deficiency are basically pregnant women, vegans, people who live in areas with low levels of iodine in the soil, and people who do not use iodized salt or supplements containing iodine.

Side effects

In some cases such as people with thyroid disorders or those that have an iodine deficiency, there may be some interactions in the parallel intake of iodine. This results in overactive thyroid glands often leading to hyperthyroidism. [23]

However, the onset of excess iodine intake can come from consuming a large amount of food that is rich in iodine such as seaweed or iodized salt. 

Iodine poisoning is quite rare and symptoms include fever, stomach pain, nausea, vomiting, burning sensation in the mouth, throat and stomach. Particularly susceptible to iodine toxicity are usually people who already suffer from thyroid problems, children, infants, the elderly. [4] [24]

What is the iodine treatment?

Radioactive iodine (RAI) is commonly used as a treatment for an overactive thyroid. It is a reliable treatment, targeting thyroid cells through radiation. It is usually taken in capsule form, while taking a sufficient amount of water after taking the tablet is usually necessary. There is a possibility that some temporary side effects may occur such as neck sensitivity, nausea, change in taste, dry eyes.

Regarding iodine supplements, most cover the daily recommended dose (ie 150 mcg for adults) so one can reap the benefits of iodine without the risk of overdosing.

  At Vita4you.gr you will find a wide variety of iodine supplements.