Iodine in Reproductive Health
What is it?
Iodine is an element that is needed in the diet. It is mostly absorbed from food in the small intestine, and travels to the thyroid glands. Once there, the iodine is bound to other molecules to make Thyroid hormones known as T3 and T4. These thyroid hormones are needed to facilitate genetic material being copied and replicated in new cells. Of course this is not the only role that thyroid hormones play, but it is the one we are most interested in here!
Why is it important in fertility?
Though it may not have much impact on likelihood of fertilisation and becoming pregnant, having good iodine intake is very important in preconception. In the first 16 weeks of gestation, the foetus cannot produce its own thyroid hormones, so relies totally on thyroid regulation by mum. Since iodine is needed for copying genetic material, it is essential in foetal brain development.Without enough Iodine, there is likely a depletion in the amount of thyroid hormones produced, and then genetic material and cell division may not happen at the correct rate in the developing brain. The World Health Organisation have stated that iodine deficiency is still the number one reason for preventable brain damage.
So how much do you need?
There is some differing information about iodine requirements un the UK, but the recommendations are in a similar ball park: European Foods Standards Agency recommend 200mcg/day in pregnancy, whereas UK Department for Health recommend 140mcg/day for all women between 19-50 years old, with no increase for pregnancy.
The body has capacity to build up iodine reserves, which is important to ensure plentiful supply during early pregnancy where use of iodine is high. Some groups of people have been found to be at risk of having low iodine intakes, and these include vegans, black women and women of Asian origin.
Where can you get it?
Milk, yoghurt, cheese, fish and eggs are all great sources of iodine. Because iodine is found in the soil, the iodine content of these foods will be dependent on the quality of feed and soil that the animals had. If you’re vegan and none of these sources are suitable, you may find that fortified non-dairy milk can help meet your iodine requirements - but be sure to read the label, as not all are fortified the same! Iodine supplements can be helpful for those trying to conceive, and VEG-1 supplement by the Vegan Society can help meet your needs. Iodine can also be found in abundance in seaweed, HOWEVER, due to the variable content of iodine in seaweed, it is not recommended as a supplement or reliable source. Too much iodine can be harmful to thyroid function, so it is helpful to be aware of your intake.
If you have any concerns about your iodine intake, or are hoping to optimise your plant-based diet prior to pregnancy, you can contact your Dietitian for more support or check the food facts with the British Dietetics Association.
References:
doi: 10.1016/j.neuroscience.2015.09.070
doi: 10.1136/pmj.77.906.217
SACN statement on iodine and health