Iodine for vegans
What is iodine and why do we need it? By plant-based dietitian, Yvonne O'Halloran
Iodine is a trace element used by our thyroid gland in our throat to make thyroid hormones. These hormones are important for controlling our metabolism. Thyroxine is made by the thyroid gland with the help of iodine, and it controls the way many of our cells work. It is also important for the growth of bones and nerves and how macronutrients (protein, fats and carbohydrates) are used in the body. According to the National Institute of Health, thyroid hormones are also essential for proper skeletal development and central nervous system development in a developing baby and in infants.
Iodine deficiency can happen even in the developed world. The 2018 National Diet and Nutrition Survey, who assess diet and nutrient intake of the UK population, found low levels of iodine in nine per cent of children aged 4-10 years, 12 per cent of children aged 11-18 years, 14 per cent of adults aged 19-64 and eight per cent of adults aged 65 years and over. Therefore, even though our requirements are relatively small at 140mcg per day, sometimes, we are still not reaching that target.
Iodine is available in three typical ways:
• Occurs naturally in some foods
• Is added to some salts (called iodised salt)
• Can be taken as dietary supplement
Iodine can be variable in plant sources, depending on how much soil the plant was grown in. The iodine content in seaweeds such as kelp, nori, wakame and kombu can be very variable, and some have been known to contain too much iodine while others have been found to be contaminated with nasties such as lead and cadmium. Other less reliable sources of plant-foods containing iodine include wholegrains, green beans, courgettes, kale, spring greens, watercress, strawberries and organic potatoes with the skin on. The amount of iodine can be quite low and changeable depending on how much iodine is in the soil.
Fortification
According to an article published in Clinical Endocrinology (Woodside, 2020), the UK is among a minority of countries with no legislative framework for iodine fortification.
Iodised salt
Iodised salt is available in some shops in the UK, however, health authorities do not recommend iodised salt as an option as we already have way above the amount of recommended sodium in our diet. However, if you do occasionally use salt, replacing with iodised salt may be a good option.
Iodine fortified plant milks
In the UK, not all plant-based milks are fortified with iodine, in fact, most are not. Make sure you check the label for ingredients such as potassium iodide or potassium iodate. Oatly plant-based milks and Alpro soya milks contain iodine similar to the quantity you would find in cow's milk.
Symptoms of Iodine deficiency
• Goiter
• Hypothyroidism
• Weight gain
• Hair loss
• Dry, flaky skin
• Depression
Summary
What is the best way to source adequate iodine in your diet? Regular use of small amounts of powdered seaweed added to soups, stews, salads and pasta dishes is an excellent way to ensure a good iodine intake.
A healthy vegan diet containing a wide range of vegetables (including some sea vegetables like seaweed, and/or iodised salt, used sparingly) should supply sufficient iodine. Aim to choose fortified plant-based milks and always read the labels to check you are selecting the correct plant-based milk to help you meet your iodine needs as a vegan.