Iodine: The mystery mineral

28th May in Blog

Iodine is often ignored when it comes to fertility. However, it is one of the most important nutrients needed for conception and development. This mystery mineral is essential in the first 1,000 days of life (including the preparation period for pregnancy).

Iodine is vital in the production of thyroid hormones and therefore thyroid function. Deficiency has also been associated with brain damage and can have significant impacts on foetal development.

Additionally, sufficient iodine intakes have shown fertility friendly links, such as promoting healthy menstruation and increasing the chances of conception. Some research even shows that women with low iodine intakes are 46% less likely to conceive per cycle.

Despite the fact that many women in the UK do not get enough iodine, deficiencies can be entirely preventable. This magical mineral just needs more of a leading role in the fertility and food line-up.

The requirements and advice for iodine vary as you hop between countries. In the UK, it is recommended for all adults to get 150 micrograms per day and for both pregnant and breast-feeding women to obtain 200 micrograms per day.

Dietary sources that are rich in iodine include, milk and dairy products, fish (especially white varieties like haddock and cod), eggs and meat. However, iodine content can vary between seasons, farming practices and soil types.

Whether you decide to go for blue, green and red top cow’s milk; the iodine content is reasonably similar. However, organic cow’s milk does tend to have a slightly lower amount.

Iodine is not naturally present in plant-based milks, for example soya, oat and almond, but some brands are getting much better at fortifying their products. Avoid purchasing organic plant-based milks as none of the necessary nutrients will have been added in. Instead, take a peek at the nutritional table on the label and if iodine is listed then prioritise those products on your shopping list.

Although seaweed and kelp can be incredibly high in iodine, it is very concentrated and therefore it is not recommended to consume these ingredients more than once per week.

Many countries have tried to combat iodine deficiency by mixing it into table salt. Whilst the UK does have iodised salt available to purchase, this is not a technique that has been largely adopted. This is largely because; a) it is very costly and b) we are advised to avoid too much added salt to protect our heart health.

If you are managing to get 2-3 servings of milk, dairy or fortified alternatives per day (1 serving = 200ml milk, an individual yogurt pot or a small match box size of cheese) and consume 2 portions of fish per week (including a combination of white and oily varieties) then you should be hitting your iodine target.

Ideally, it is best to have longer-term, sufficient iodine intakes. However, individuals that cannot meet recommendations due to food preferences or dietary needs (such a allergies, intolerances or ethical and environmental considerations) may need to consider a tablet form.

The world of nutritional supplements can be incredibly confusing. Here are some top tips if you feel that iodine supplementation may be necessary for you:

  1. Avoid iodine supplements that contain more than 150 micrograms/day
  2. If you are already taking a multivitamin and mineral tablet, or a combined pregnancy supplement, you may already be taking iodine without realising it. There is no need to double up (and this can actually be very unhelpful!)
  3. Do not use seaweed or kelp supplements as the levels of iodine can be both incredibly high and inconsistent
  4. If you have the time to plan, it is best to supplement (if needed) for several months before trying to conceive

Unfortunately, we cannot accurately measure iodine levels using blood tests. Therefore, do not hand over cash to companies that claim they are able to do this. If you are concerned about your intake it is best to have your diet professionally analysed by a registered dietitian.

If you would like more information about nutrition and lifestyle, please go to Website: or email to enquire about an appointment.

Written by Alex Ballard, UK Registered Dietitian
Instagram: @alextalksdiet


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