The team modelled typical UK products, including 146 non-dairy milks, 76 yoghurts and 67 cheeses, often based on soya, almonds or oats. Fortification was uneven: 61 per cent had added calcium, 46 per cent vitamin B12, 19 per cent riboflavin and only 12 per cent iodine.
Switching from dairy milk, cheese and yoghurt to plant-based alternatives could leave people short of iodine and other micronutrients, especially teenage girls and women of childbearing age, according to UK modelling published this week.
White fish such as cod or haddock, eggs, and yoghurt or kefir for those who eat them can also supply iodine. The researcher advised against relying on seaweed or kelp supplements because iodine levels vary widely and can be excessive.
Requiring iodine in all non-dairy alternatives would prevent average declines in the scenarios, the study found. Adding iodised salt to bread also reduced the share of teenage girls with inadequate intake in the models.
Plant-based milks, cheeses and yoghurts have grown in popularity, though some consumers have shifted back. Some companies already fortify substitutes; organic drinks typically do not.
Replacing a fifth to a third of dairy with those alternatives, at current market fortification, raised modelled iodine deficiency from 54 per cent to 65 per cent among adolescent girls and from 32 per cent to 42 per cent among women aged 19 to 49.
A one-third swap cut iodine intake by 9 to 21 per cent in the models, with calcium, riboflavin and vitamin B12 also falling if products were not fortified. A full switch to non-dairy options pushed inadequate iodine to 80 per cent of teenage girls and 72 per cent of teenage boys.
“The population groups that seem to be at risk and have the lowest intakes were the young women and women of childbearing age, and that’s the key life stage where iodine is particularly important,” a researcher said. “For anyone choosing plant-based milk, I’d recommend checking the label and choosing one fortified with iodine, such as Alpro,” the researcher said. “Organic drinks aren’t fortified with added nutrients, so they’re unlikely to provide iodine.”.
Iodine is used by the thyroid to make hormones that regulate metabolism and support growth and brain development. Scientists said that is why shortfalls in young women matter most.