Iodine – an important nutrient for plant-based and vegan diets
PhD student Martha Redway presents key points to make sure the nutrient is not overlooked.
Was your New Year’s resolution to eat more plants? Maybe you even took part in Veganuary, an international campaign to go animal product-free for the month of January? If you’ve decided that you’d prefer a tempeh toastie over a bacon sandwich and have opted to make the switch to a plant-based lifestyle, there are a few things you’ll want to consider. The British Dietetic Association provides an excellent set of fact sheets on plant-based nutrition, and plenty of information on key nutrients like calcium, vitamin B12, and iron. But have you ever thought about where you get your iodine from?
Iodine is an essential mineral nutrient, used by the body to make thyroid hormones. These hormones regulate many processes in the body like metabolism and growth and are especially important during pregnancy and lactation to support the healthy growth and development of the baby. The recommended amount of iodine that adults should consume each day is 150ug, or 250ug if you are pregnant or breastfeeding.
In the UK, the main food sources of iodine are milk, dairy products, and (sea) fish. Excluding these three foods from your diets means that you should be paying closer attention to the foods you choose instead, to ensure that you meet iodine intake recommendations. This is important to avoid the potential negative consequences that arise from iodine insufficiency (such as thyroid dysfunction).
Vegan sources of iodine:
- Fortified milk alternatives – with an enormous selection of plant-based milk alternatives to choose from, make sure you opt for one that is fortified with iodine. Check the label for ‘potassium iodide’ or ‘potassium iodate’.
- Salt – salt in the UK is not routinely fortified with iodine, so switch your regular salt for iodised salt (look for ‘iodated’ or ‘potassium iodide/iodate’ on the label). Keep in mind that the recommendation is that adults shouldn’t have more than 6g of salt each day as high salt intakes are associated with hypertension (i.e. increased blood pressure).
- Seaweed – to be consumed with caution! One gram of nori (Porphyra species), commonly used in sushi, contains around 16µg of iodine, but although seaweed can be a great plant-based iodine source, remember to always check the label and don’t eat too much! Iodine content in seaweeds can vary a lot between species and certain seaweeds, like kelps (Laminaria species), can contain more than 8000ug of iodine per gram, which is dangerous for your thyroid. [you can read more about seaweed as a food here]
- Supplements – taking a daily supplement containing 150ug of iodine is the easiest and most reliable way to meet your daily intake goal. Avoid seaweed-based supplements, in particular those not giving details of iodine dose or seaweed species and discuss the use of supplements with a healthcare professional to make sure they are suitable for you.
If you feel you need further advice about how to meet iodine recommendations, or any aspect of plant-based nutrition, you can seek personalised advice from registered dietitian or AfN-registered nutritionist who can support you to ensure that your diet is healthy, balanced, and iodine replete.
Research into plant-based diets at the University of Glasgow
Whether you’re a brand-new vegan or have been following a plant-based diet for years or decades, we’re interested in your views on diet and nutrition. We are currently conducting a large cross-sectional survey of vegans in the UK to gather information about their dietary habits, supplement usage, and motivations for following a plant-based lifestyle. The survey takes around 30 minutes and can be accessed by following this link: https://glasgow-research.onlinesurveys.ac.uk/vegan-survey
If you live or work locally to Glasgow, you can also opt-in to come to our research unit on the Glasgow Royal Infirmary campus for nutritional assessment as part of the study. The visits last around 45 minutes and you will receive £10 compensation for your time. If you are interested in organising a visit, you can express interest at the end of the survey and a member of the research team will be in touch. Alternatively, you can contact Martha directly at firstname.lastname@example.org.
Martha Redway is a PhD student in the Section of Human Nutrition, School of Medicine at the University of Glasgow. Her research focusses on iodine, the nutritional adequacy of plant-based diets and the suitability of seaweed as a dietary component in the UK food supply.