A new study has raised concerns about the health impacts of replacing dairy with plant-based milks, yoghurts, and cheeses. Source: independent.co.uk.
Key Findings on Nutrient Deficiencies
Researchers from the University of Surrey and Queen’s University Belfast analysed 146 plant-based milks, 76 yoghurts, and 67 cheese products.
The study focused on four key nutrients: iodine, calcium, vitamin B12, and riboflavin (vitamin B2).
- Only 12 per cent of plant-based items contained added iodine.
- 61 per cent had added calcium.
- 46 per cent had vitamin B12.
- 19 per cent had riboflavin.
Even partial swaps of dairy with plant-based alternatives led to declines in all four nutrients.
For example, replacing 20–35 per cent of dairy with plant-based products increased inadequate iodine intake among girls aged 14–18 from 54 per cent to 65 per cent.
In women aged 19–49, that figure rose from 32 per cent to 42 per cent.
If all dairy was replaced, iodine inadequacy reached 80 per cent in teenage girls and 72 per cent in teenage boys.
Calcium intake also dropped significantly. Among boys aged 14–18, inadequate intake rose from 30 per cent to 47 per cent.
For girls the same age, it increased from 54 per cent to 70 per cent.
For riboflavin, men aged 19–49 saw inadequate intake rise from 14 per cent to 26 per cent.
For women, the figure went from 29 per cent to 50 per cent.
Even half-replacements of dairy led to a 39 per cent increase in riboflavin inadequacy in this group.
Why These Nutrients Matter
Calcium is essential for building strong bones and teeth and helps regulate muscle contractions, including the heartbeat.
Vitamin B12 supports the nervous system and blood cell health.
Vitamin B2 is important for skin, eyes, and the nervous system.
Dr Sarah Bath, lead author from the University of Surrey, said the UK lacks a universal iodine fortification policy like salt iodisation in many other countries.
She noted that people often do not realise iodine is needed for thyroid hormones, which regulate metabolism and brain development.
She added that dairy is a major source of iodine in the UK, and that most plant-based alternatives contain very low levels unless fortified.
What the Study Suggests About Policy
The research suggests mandatory fortification of plant-based foods could help improve nutrient intake.
However, even with fortification, 59 per cent of teenage girls still had inadequate iodine intake.
Dr Katie Nicol, co-author of the study, said nutrition policy must keep pace with environmental goals.
She stressed that shifts to plant-based diets should not come at the cost of public health.
She said food fortification is one solution, but government action is needed to make it happen.
Expert Responses and Counterpoints
Professor Mairead Kiely from the Cork Centre for Vitamin D and Nutrition Research said animal-source foods are a key source of nutrients like calcium, iodine, riboflavin, and vitamin B12.
She said plant-based dairy alternatives, unless properly fortified, do not match the nutrient levels of milk, yoghurt, and cheese.
She highlighted that adolescents and women of reproductive age already have low intakes of these nutrients.
She said moderate reductions in dairy are unlikely to harm most people, but those who already consume little dairy may face worsening deficiencies.
Dr Janette Walton, lead investigator for Ireland’s national dietary surveys, said dietary guidelines now encourage large shifts to plant-based diets for sustainability.
She said the health consequences for teenage girls and young women must be considered in such transitions.
Scientific Limitations and Debate
Tom Sanders, professor emeritus at King’s College London, pointed out a key weakness: iodine levels in food depend on soil composition.
He said milk is not naturally high in iodine; the high levels found in milk come from salt licks given to dairy cattle.
He noted that seafood is the best natural source of iodine.
He added that iodine deficiency is rare in the UK, based on urinary iodine levels, because food is sourced from many countries.
Emily Angus, senior dietitian at The Vegan Society, said the claim that replacing dairy with plant-based alternatives reduces iodine intake is misleading.
She said most plant-based milks available in the UK are fortified with calcium and vitamin D as a minimum.
She said the Vegan Society recommends choosing fortified dairy alternatives, which are considered safe and acceptable for children from age one, according to 2025 SACN guidance.
What This Means for Consumers
The study shows that not all plant-based milks are equal in nutrient content.
Fortification varies widely across products.
Some people may be at higher risk if they reduce dairy intake without ensuring their plant-based alternatives are fortified.
Children, teenagers, and women are especially vulnerable to nutrient deficiencies when switching from dairy to plant-based products.
Consumers should check labels to ensure products contain added iodine, calcium, vitamin B12, and riboflavin.
Public health policy may need to address fortification of plant-based foods to prevent widespread nutrient gaps.
The research does not suggest a complete ban on dairy, but highlights the need for informed choices and possible policy action.
Sources & further reading
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