Partial replacement of milk and dairy products with plant-based alternatives – would fortification of bread reduce the impact on iodine intake?

Plant-based dairy alternatives (PBDAs) consumption has assumed a more significant role in populations shifting to more sustainable eating habits. However, PBDAs do not necessarily replace the nutrient value of cow’s milk and dairy products, particularly that of essential micronutrients such as iodine (1) . Cow’s milk and dairy products are the primary source of iodine in the UK diet (2) , and substituting with PBDAs may negatively affect iodine intake. Here, we aimed to (i) investigate the implications for iodine intake and adequacy of partial replacement of milk, cheese, and yoghurt with commercially available PBDAs per UK Net Zero recommendations (3) and (ii) evaluate the potential of introducing bread products made using iodised salt as prophylaxis against iodine deficiency in population intakes due to the proposed changes. The present study used the dietary modelling software DaDiet (4) to examine iodine intake in the diets of children aged 1.5-13 years and females aged 14-49 years. We used data from the National Diet and Nutrition Survey (2016-2019) and brand-level iodine concentration data (5) . Firstly, several scenarios that accounted for the population impact of replacing 20% or 35% of milk and dairy product consumption with PBDAs were modelled. Secondly, we modelled the changes by substituting salt in bread with iodised salt at a 30 µg/kg concentration. Relative to the usual diet, we calculated the change in iodine intake and the proportion with intake below the UK Lower Reference Nutrient Intake (LRNI) or above the Upper Limit (UL). Replacing 20% of dairy products with PBDAs would result in a meaningful decrease in usual iodine intake in all population groups, except females aged 14-18 years, without impacting the population proportion below the LRNI. A 35% replacement would result in a meaningful decrease in iodine intake (9-20%) compared to the usual diet for all population groups. A 35% replacement would also increase the proportion of females aged 19-49 years with iodine intakes below the LRNI to 21%. Adding iodised salt to bread products would increase the usual iodine intake across all population groups and decrease the proportion of intakes below the LRNI (2-14% change). Particularly for females aged 14-18 years, where 40% increases in iodine intake were observed (97 to 136 µg/day) and would not have a meaningful impact on the proportion above the UL in any population group. Introducing iodised salt in bread products would counteract the negative effect of PBDAs on iodine intake in all population groups. Replacing milk and dairy products with PBDAs per current UK Net Zero goals would reduce population iodine intake unless measures are implemented to minimise the impact on usual iodine intake. Introducing iodised salt to bread products is one countermeasure that would minimise the impact on iodine intake without increasing the population above the UL.