Swapping dairy for unfortified plant drinks: a risk of iodine shortfall
· BehindLines newsroom
Swapping dairy foods for plant-based substitutes that are not fortified could lead to shortfalls of some nutrients, notably iodine, according to a modelling study published on 4 November 2026 in The Lancet Planetary Health, as described in a press release distributed by EurekAlert.
According to that release, the team, led by Sarah Bath of the University of Surrey (UK) with Katie Nicol and Anne Nugent (Queen's University Belfast), used data from the UK National Diet and Nutrition Survey covering more than 3,500 people aged 18 months to 100 years. It simulated replacing milk, yoghurt and cheese with plant-based alternatives and looked at four micronutrients: iodine, calcium, riboflavin and vitamin B12. It is described as the first study of its kind in the UK.
Iodine was the most sensitive nutrient. According to the release, replacing 20 to 35 percent of dairy with unfortified alternatives would raise the share of adolescent girls with inadequate intake from 54 to 65 percent, and of women aged 19 to 49 from 32 to 42 percent. With full replacement, inadequacy reached 80 percent among adolescent girls and 72 percent among adolescent boys.
Mandatory fortification of plant-based alternatives would prevent declines in intake for the nutrients studied, but iodine inadequacy would remain at 59 percent among adolescent girls. Adding iodine-fortified bread would bring it down to 37 percent; the authors conclude that combining both measures works best. Bath says the UK is particularly vulnerable because it has no iodine fortification policy.
The background is known: according to a University of Surrey press release from August 2024, a WHO/Europe and Iodine Global Network report co-authored by Bath noted that many soy and oat drinks are not fortified with iodine and that the UK has no salt iodisation policy.
What remains unknown: this is a model built on hypothetical scenarios, not a measurement of actual intake. Replacement products were drawn from those on the market with equal chance, since contents vary, and the results apply to the UK context. We have not read the full paper.