Concerns over the environmental impact of animal products have prompted a shift towards plant-based alternatives (PBA), which often lack important nutrients like iodine. This study aimed to assess the changes in iodine fortification of plant-based milk, yogurt, cheese, and seafood alternatives available in UK supermarkets from 2020 to 2024. Iodine is crucial for thyroid function and cognitive development, yet many PBAs are unfortified.
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Supermarkets were surveyed online annually each December, revealing a 55% increase in PBA from 300 products in 2020 to 466 in 2024. This included 246 milk alternatives, 81 yogurts, 110 cheeses, and 29 seafood products. In 2024, 48% of non-organic milk alternatives were fortified with iodine, compared to 5% for yogurt and 4% for cheese alternatives. This represents a rise from 28%, 6%, and 0%, respectively, in 2020. None of the seafood alternatives were fortified. While fortified PBA provided 75-83% of the iodine found in cow’s milk, most remained deficient in iodine overall. Fortification rates for iodine lagged behind those for calcium and vitamin B12 (48% vs. 88% and 71%, respectively).
The shift in dietary patterns in the UK, with an increasing number of people reducing animal-source food intake—from 28% in 2017 to 39% in 2019—has created an urgent need for proper fortification. Many consumers turn to PBAs for various reasons, including health issues, ethical concerns, and dietary preferences. However, the absence of mandatory fortification guidelines means the micronutrient profiles of PBA vary significantly.
Iodine plays a vital role in health. It is essential for thyroid hormone production, which regulates metabolism and brain development. In the UK, iodine intake is generally low, particularly among vulnerable groups such as pregnant women and children. While iodine deficiency was historically common, improvements in the 20th century led to a generally assumed sufficiency. However, recent data indicate a resurgence in deficiency, particularly among women and adolescents.
Given that dairy products contribute significantly to iodine intake—48% for children aged 4-10 years—substituting these with unfortified PBA may increase the risk of inadequate iodine consumption. This is also evident in the very low rates of iodine fortification across various PBA categories as indicated by market surveys conducted in past years.
The study highlights the need for improved public health guidance and fortification policies to counter iodine insufficiency, especially as plant-based diets gain popularity. This detailed assessment offers critical insights necessary for informing public health recommendations and ensuring consumers can opt for adequately fortified alternatives.