A new study published in the Lancet Planetary Health found that switching from dairy products to plant-based alternatives could lead to deficiencies in vital micronutrients, especially among young people and women. Even moving partly to vegan alternatives to milk, cheese and yoghurt could lead to falls in iodine, calcium, riboflavin and vitamin B12 if the substitutes, often based on soya, almonds or oats, are not fortified, scientists said.

The greatest concerns surround iodine, a trace element used by the thyroid gland to produce hormones that regulate metabolism and support healthy growth and brain development. More than half of UK teenage girls already have inadequate iodine intake, the researchers said.

Replacing a fifth to a third of dairy intake with plant-based alternatives would lead to prevalence of iodine deficiency rising from 54% to 65% of adolescent girls and from 32% to 42% of women aged 19 to 49 years old, according to modelling based on typical market levels of fortification.