If you were asked to name some of the most important vitamins and minerals we need in our body, you might be able to reel off a few with ease: vitamins A, B, C, D and E, magnesium, calcium, iron and so on. It’s perhaps less likely that you’d mention something like iodine. 

This essential mineral is often overlooked, but it plays a key role in our bodies, helping the thyroid gland with hormone production and keeping the metabolism working as it should. And with recent research suggesting that iodine deficiency is now a re-emerging issue in countries like the UK and the US, it’s time to start paying more attention to this important element. 

Iodine plays a pivotal role in our thyroid health and therefore can have an impact on many things in our body, including our metabolism and brain function.

“Iodine is essential for our thyroid gland to function correctly,” explains nutritionist Dominique Ludwig, the founder of Renew Reset Recharge. “The thyroid gland is located in the front of our neck and requires iodine to make the thyroid hormones thyroxine (T4) and triiodothyronine (T3), which help to regulate our metabolic rate, growth and development.”  

Our thyroid hormones impact a number of vital processes and readings, including our body temperature, energy levels, growth and even weight. This means that inadequate iodine levels (which can potentially lead to an underactive thyroid, also known as hypothyroidism) can have a knock-on effect on all of these things.

The mineral is also really important during pregnancy to ensure the development of a healthy brain, skeleton and metabolism, and when breastfeeding. Many studies have highlighted the risk of low iodine levels. with one review suggesting that babies whose birth mothers had an iodine deficiency when pregnant were more likely to have intellectual delays and a lower verbal IQ.  

On a more surface-deep level, it’s believed that iodine can also play a role in keeping our complexion healthy and robust. “The European Food Safety Authority (EFSA) has found that iodine also helps to maintain healthy skin, and there’s also evidence that iodine and a normal functioning thyroid contributes to healthy hair and stronger nails, too,” says nutritionist Dr Naomi Beinart, who is currently working with seaweed supplement brand Doctor Seaweed.  

So, what happens if our iodine levels are too low? In truth, symptoms can be hard to miss or easily misinterpreted as something else.

“The link between iodine deficiency and thyroid health is critical, and the symptoms of even mild hypothyroidism are broad due to the impact the thyroid has on the body,” explains Beinart. “Symptoms can include weight gain and difficulty losing weight, sensitivity to cold, brittle hair and nails, loss of libido, low energy and tiredness, cognitive impairment, and many others.”

It’s also worth mentioning that excess iodine can be harmful to the body. The key – as with most things – is to get the right balance.  

Iodine is a naturally occurring mineral that we can’t produce ourselves, so we rely on consuming the right amount through our diet. Ideally, we’re meant to consume about 140-150 micrograms (μg) a day, rising to around 200μg when pregnant or breastfeeding. Good sources of iodine include:

Seaweed

Seaweed is a great source of iodine and other vitamins, minerals and antioxidants. The amount of iodine present in seaweed depends largely on what type of seaweed you’re eating, where it’s been grown and how it’s been prepared. Kelp is thought to be one of the most iodine-rich varieties. You can now buy seaweed in a variety of forms – as dried ‘thins’, flakes or crisps, or as supplements.

Dairy

Iodine can be found in dairy such as yoghurt, milk and cottage cheese, although Ludwig points out that cheddar and hard cheeses contain less iodine than soft cheese as much of the mineral is found in the whey (more of which is discarded when producing hard cheeses). 

Bear in mind too that iodine levels in these products can vary at different times of the year. “Seasonal variations to the iodine in cows’ milk can occur as the cows are more reliant on their mineral-fortified feeds in winter than summer,” Ludwig adds.  

Fish

White and oily fish and seafood all contain good levels of iodine, with cod being hailed as one of the best sources. Look out for lean fish, which contains a higher amount of the mineral when compared to fatty fish.

Eggs

Yes, your trusty scrambled eggs can also contribute to your iodine intake, with experts estimating that an average egg contains around 25mg of this mineral.  

Supplements and fortified foods

In the past – when iodine deficiency was more prevalent – people would use iodised salt as a way to increase their intake, and this can still be purchased in some supermarkets today. There are also a number of other iodine-focused supplements out there designed to help ensure we’re getting the right amount. If you’re considering supplementing your diet, it’s always best to check with a healthcare professional first as iodine supplements aren’t suitable for everyone.  

If we’re not following a well-balanced diet we can be at risk of all sorts of nutrient-deficiencies, and iodine is no different.

“Today, globally, iodine deficiency is estimated to affect up to 2.2 billion people and some studies are indicating that iodine deficiency is something that we should, as health professionals, be taking seriously again in the UK,” says Ludwig. “While it was virtually eradicated there is now a real possibility that iodine deficiency could increase due to the reduction in iodine rich-foods in the diet.”

What Ludwig is referring to is the fact our diet patterns have changed considerably in the last decade or so, particularly as more people have tried to limit or cut out dairy and animal proteins from their diet.

“Some of the primary sources of iodine are fish (especially white fish) and dairy. Both foods are in declining intake, and with the rise of plant-based milks that have no iodine naturally, this can have an impact on iodine levels in the UK,” explains Beinart. This does mean that vegans, or those who don’t eat dairy products and fish, can be at a higher risk of deficiency than meat and dairy consumers.

There are other reasons for the UK’s declining iodine status: researchers note that changing farming practices and the fact we have no iodine fortification programme in place could also play a part.

Beinart points to one study from 2011 that found two-thirds of the 15-year-old female participants were iodine deficient and other research that ranks the UK within the top 10 most iodine-deficient nations in the world.

Experts agree that awareness is key and many campaigns recently have focused on drawing attention to the importance of the mineral. As always, if you’re concerned about your own iodine levels, the best thing to do is speak to your GP who can advise if supplementation is required.  

Images: Getty