Swapping dairy for oat or almond milk could leave you short of iodine, study warns
Swapping cow’s milk for oat or almond milk is often seen as a healthy choice. But a new UK study warns that replacing dairy with unfortified plant-based products could leave many people short of important nutrients — especially iodine.
Researchers from the University of Surrey and Queen’s University Belfast published the findings in the journal Lancet Planetary Health, the University of Surrey announced. The university called it the first study of its kind in the UK.
What the researchers did
The team used data from more than 3,500 people aged from 18 months to 100 years in the National Diet and Nutrition Survey. They then modelled what would happen to people’s intake of four key nutrients found in dairy — iodine, calcium, riboflavin and vitamin B12 — if milk, yoghurt and cheese were replaced with plant-based alternatives currently on sale.
Even partial swaps led to marked falls in all four nutrients. Iodine was the most affected. Replacing just 20 to 35 per cent of dairy raised the share of teenage girls with inadequate iodine intake from 54 to 65 per cent, and among women aged 19 to 49 from 32 to 42 per cent. With full replacement, inadequacy rose to 80 per cent of teenage girls and 72 per cent of teenage boys.
Why iodine matters
Iodine is needed to make thyroid hormones, which help regulate metabolism and support growth and brain development. It is particularly important before and during pregnancy.
“The UK is particularly vulnerable to iodine insufficiency due to a lack of an iodine fortification policy such as universal salt iodisation, which many other countries have,” said lead researcher Dr Sarah Bath. She added that many people do not realise dairy is a major source of iodine in the UK, and that plant-based alternatives have very low iodine levels unless they are fortified.
A market survey cited in coverage by UNILAD found that only a small number of the plant-based products examined were fortified with iodine.
What could fix it
The researchers tested several solutions. Making fortification of plant-based alternatives mandatory prevented most of the declines, though iodine was still inadequate in 59 per cent of teenage girls. Adding iodine to bread had a bigger effect, cutting inadequacy in that group to 37 per cent. The best results came from combining both measures.
The study does not say people should stop using plant milks. Its message is that the shift towards more sustainable diets should not come at the cost of health. “Fortification of foods is one way that this could be achieved however government policy is needed to make this happen,” said co-author Dr Katie Nicol. The Guardian also reported on the findings.
For shoppers, the simple takeaway is to check labels: if you use plant-based alternatives, look for products fortified with iodine, calcium and B12, and speak to a GP or dietitian about any concerns.
