Micronutrient fortification of plant-based dairy and seafood alternatives – a study of changes over a five-year period

Concerns about the environmental impact of animal-source foods have led to a shift toward plant-based alternatives (PBAs). While dairy products and seafood are rich in iodine, an essential nutrient for thyroid function and cognitive development, PBAs often lack iodine fortification. As the market expands, there is increasing concern that individuals replacing dairy products and seafood with unfortified PBAs may be at risk of iodine deficiency. This study assessed changes in the iodine fortification of plant-based milk, yoghurt, cheese, and seafood alternatives through a cross-sectional survey of UK supermarkets (2020-2024). Supermarkets were surveyed online each December, and product nutrition and ingredient data were extracted. Between 2020 and 2024, the number of PBAs increased by 55%, with 466 PBAs identified in 2024, including milk (n=246), yoghurt (n=81), cheese (n=110), and seafood alternatives (n=29). Iodine fortification was inconsistent: in 2024, 48% of non-organic milk alternatives were fortified, while only 5% of non-organic yoghurt and 4% of cheese alternatives contained iodine. In comparison, 28%, 6% and 0% of non-organic milk, yoghurt and cheese alternatives were fortified with iodine in 2020. No fortified seafood alternatives were identified. Fortified PBAs provided 75-83% of the iodine content of cow's milk, but most remained poor iodine sources. Although iodine fortification has increased, it lags behind that of calcium and vitamin B12 (48% vs. 88% and 71%, respectively). Given iodine's critical role in health, clearer public health guidance and improved fortification policies are needed. Increased reliance on PBAs may exacerbate iodine insufficiency in the UK without intervention.