By Ahmed Abdelsalam
Swapping dairy products for plant-based alternatives such as oat or almond milk could increase the risk of nutrient deficiencies, according to a study published in the Lancet Planetary Health journal. Researchers from the University of Surrey and Queen’s University Belfast analysed 146 plant-based milks, 76 yoghurts and 67 cheese products, finding that even partial replacement of dairy led to declines in iodine, calcium, vitamin B2 and vitamin B12 intake.
Children and women most affected
The research, based on data from more than 3,500 participants in the National Diet and Nutrition Survey, showed that children, teenagers and women of reproductive age faced the greatest increases in inadequate nutrient intake. For example, replacing 20-35 per cent of dairy with plant-based options raised inadequate iodine intake among girls aged 14-18 from 54 per cent to 65 per cent, and among women aged 19-49 from 32 per cent to 42 per cent. A full swap pushed iodine inadequacy to 80 per cent in teenage girls and 72 per cent in boys of the same age.
Fortification gaps
Only 12 per cent of the plant-based products studied contained added iodine, while 61 per cent had added calcium, 46 per cent had vitamin B12 and 19 per cent had riboflavin (vitamin B2). The researchers found that even fortified plant-based alternatives did not fully match the nutrient profile of dairy, and mandatory fortification policies would still leave iodine inadequacy at 59 per cent among teenage girls.
Call for policy action
Lead author Dr Sarah Bath, associate professor at the University of Surrey, highlighted the UK’s lack of universal salt iodisation and low public awareness of iodine’s role in thyroid function and brain development. Co-author Dr Katie Nicol said nutrition policy must evolve alongside environmental targets to avoid compromising public health, advocating for government-mandated fortification. Professor Mairead Kiely of the Cork Centre for Vitamin D and Nutrition Research warned that adolescents and women already have low intakes of calcium, iodine and riboflavin, making further reductions concerning.
Differing views
Professor Tom Sanders of King’s College London noted that iodine deficiency cannot be reliably predicted from dietary records alone, as soil content varies, and pointed out that milk’s iodine comes from supplemented cattle feed. Emily Angus of The Vegan Society said the study’s framing was misleading, as most UK plant-based milks are fortified with calcium and vitamin D, and fortified alternatives are considered safe from age one under recent guidance.
