Most of us want to do what we can to boost our immune systems. But while nutrients like vitamin A, C, and D get a lot of attention, others like iodine tend to be lesser known.

Yet, iodine is an essential mineral the body needs to function properly. It’s involved in metabolism, thyroid and brain health, and the running of our immune and nervous systems.

So, what exactly is iodine, what are its functions, and how can you make sure you’re getting enough?

Here’s everything you need to know.

What is iodine?


Iodine is a mineral found naturally in seawater and the Earth’s soil. It’s one of the nine trace minerals that our bodies need – and while we don’t need as much of it as other major minerals like calcium and magnesium, iodine is still essential for our health.

Approximately 70-80% of the body’s iodine is found in the thyroid because it’s involved in the production of thyroid hormones. As a result, iodine is responsible for things like regulating body temperature, metabolic rate, nerve and muscle function, blood cell production, reproductive function, and cell growth.

By controlling the rate at which body cells use oxygen, thyroid hormones also affect how much energy the body uses when resting.

Since the body can’t produce iodine itself, we have to get it through our diet or supplementation.

What are the health functions and benefits of iodine?

What are the health functions and benefits of iodine

The main roles of iodine revolve around thyroid health, immune function, and support of the brain and nervous system. Though, as you’ll see, it’s just as important to make sure you’re not getting too much iodine, as it is to get too little.

We’ll take a closer look at the benefits of iodine below.

Iodine promotes thyroid health

The thyroid gland, which is found at the bottom of the neck, helps to regulate the production of hormones that control metabolism, heart health, and much more.

Iodine is needed to produce these thyroid hormones, so if you don’t have enough, production can decrease.

Maintaining the optimal amount of iodine in the thyroid, though, can be a delicate – but very important – balance to achieve. This is because research shows that too much iodine can initiate or aggravate symptoms of an overactive thyroid.

Iodine is needed for immune system function

Iodine is essential for immune system function. Studies suggest that, together, iodine and thyroid hormones offer constant surveillance of the development of abnormal cells that could harm our health. For example, iodine has been shown to help prevent abnormal bacterial growth in the stomach.

Other studies have also found that iodine may boost immune cell function. However, again, it’s noted that too much iodine can easily cause dysfunction in the immune system – so it’s important to get the balance right.

Iodine is important for a healthy metabolism

A healthy thyroid gland is essential in keeping your metabolism on track and, as we’ve seen, iodine is important for thyroid function. Research shows that when thyroid hormone levels are too low, your body burns fewer calories at rest, which means more of the calories you eat are stored as fat.

As a result, having steady levels of iodine (and therefore thyroid hormone levels) is linked to a person’s ability to achieve healthy weight loss and maintain a healthy weight.

Having a well-functioning metabolism is important for health because it provides the body with the energy required to carry out essential body functions – such as breathing and digestion.

Iodine plays a role in the nervous system and brain health

Iodine plays a key role in the functioning of our nervous system. According to research, various parts of the brain are affected by a lack of iodine – including the hippocampus (the part of the brain that affects memory), neurotransmitters, the protective myelin that coats our nerves, and the whole cognitive process itself.

This study found that people with low levels of thyroid hormones (which require iodine to be produced) had a smaller hippocampus. This is significant because research has linked health conditions like Alzheimer’s disease, depression, and stress with having a small hippocampus. The size of the hippocampus is sometimes used to track the progress of Alzheimer’s disease.

Iodine plays a role in the nervous system and brain health

Iodine can boost skin health

As well as regulating skin moisture levels, iodine also plays a role in skin repair by helping to heal cuts and scars. For example, this study found that not having enough iodine can reduce the rate of skin cell regeneration and cause dry, flaky skin.

Iodine also helps to regulate the hormones that are responsible for acne breakouts.

However, it’s important not to consume too much iodine, as research shows this can be harmful.

Iodine is important for fetal development

It’s particularly important for pregnant women to get enough iodine because it’s a key nutrient in fetal development – especially in relation to the brain and central nervous system.

For example, studies show that iodine deficiency during pregnancy can cause brain damage to the fetus, while also increasing the risk of low birth weight and infant mortality.

Iodine may help to treat fibrocystic breasts

Fibrocystic breasts is a benign (non-cancerous) condition where abnormal growths cause breasts to feel lumpy. These growths tend to appear and disappear at different times during the menstrual cycle – or may build up over time.

Studies have revealed that iodine deficiency is commonly found in women with fibrocystic breasts. And because iodine helps to protect against the development and spread of abnormal cells, research suggests that getting enough iodine could help to prevent fibroids from appearing.

Iodine can help to manage an overactive thyroid

An overactive thyroid – also known as hyperthyroidism – is where the thyroid produces too much of the thyroid hormones.

Typically, when the thyroid gland receives signals from the thyroid-stimulating hormone (TSH), it makes thyroid hormones. However, if you don’t have enough iodine, the thyroid can’t make enough hormones in response to these signals.

To compensate for low iodine levels, the thyroid gland works harder and harder in an effort to make more thyroid hormones, causing it to become ‘overactive’.

According to research, most cases of an overactive thyroid can be treated by increasing intake of iodine.

Iodine can be used to treat thyroid cancer

Radioactive iodine (RAI) is a treatment that uses radiation to treat thyroid cancer. RAI can be taken as a capsule that you swallow.

Depending on the case, it may be given to destroy any thyroid tissue remaining in the neck after surgery, to treat thyroid cancer without surgery, or to reduce the risk of thyroid cancer coming back.

When taken orally, radioactive iodine destroys thyroid cells – including cancerous ones. The reason RAI can be used as a treatment for thyroid cancer is because it doesn’t affect cells in other parts of the body in the same way. This is because other cells don’t absorb as much iodine as thyroid cells.

How can I make sure I’m getting enough iodine?

How can I make sure I’m getting enough iodine

According to the NHS, adults need 140 micrograms of iodine a day.

Good sources of iodine include eggs, seaweed, cod, tuna, shellfish, beef liver, chicken, cow’s milk, and other dairy products. Iodine can also be found in some plant foods – such as cereals and grains.

However, levels will vary depending on the amount of iodine present in the soil where the plants were grown. Some types of plant-based drinks – for example, soya and oat milk – are also fortified with iodine.

Most people should be able to get all the iodine they need by following a healthy, balanced diet. But those following a vegan diet have a slightly higher risk of not consuming enough iodine. The Vegan Society website has more information about how to make sure you’re getting enough iodine when following a vegan diet.

If you think you’re not getting enough iodine through your diet, you might like to consider taking an iodine supplement. Though, it’s important to speak with your doctor before taking any new supplements, as they’ll be able to advise you on the best course of action.

Taking high doses of iodine for a long period of time could alter the way your thyroid gland works, which, in turn, can lead to various symptoms or complications. However, according to the NHS, taking 0.5mg or less of iodine supplements a day is unlikely to cause harm.

What are the symptoms of iodine deficiency and who’s at risk?

What are the symptoms of iodine deficiency and who’s at risk

Anyone can develop iodine deficiency by not getting enough iodine from their diet. However, those most at risk of becoming iodine deficient include people following a vegan diet, and pregnant or breastfeeding mothers who require slightly more iodine.

There are a few symptoms to look out for when it comes to iodine deficiency. These include…

  • Weight gain (as a result of a disrupted metabolism)
  • Feeling weak and tired
  • Hair loss
  • Dry skin
  • Slower heart rate
  • Swollen neck
  • Feeling cold
  • Heavy or irregular periods

If you’re worried about iodine deficiency, it’s important to arrange an appointment with your doctor. They’ll be able to tell you whether you’re deficient or not, usually via a urine test.

Final thoughts…

Iodine might not be the first thing you think of when it comes to nutrients needed for health and wellbeing. However, due to its role in thyroid function, regulation of the nervous system, and brain health, it’s important to make sure you’re getting enough.

The good news is that the majority of people are able to get their required dose of iodine through a healthy balanced diet. But otherwise, there are options for supplementation available.

For more information on other essential vitamins and minerals, head over to the diet and nutrition section of our website. Here, you’ll find a range of delicious recipes and healthy eating tips.

How do you make sure you’re getting enough iodine? Has anything from this article surprised you? We’d be interested to hear from you in the comments below.