Study warns plant-based dairy swaps may reduce key nutrient intake

Replacing dairy foods, even partly, with unfortified plant-based substitutes could leave people short of important nutrients, according to a new study.

Researchers at the University of Surrey, working with colleagues at Queen’s University Belfast, examined how swapping milk, yoghurt and cheese for commercially available plant-based alternatives affects micronutrient intake.

The study found that children, teenagers and women were the groups most affected by the change. The researchers said mandatory fortification of plant-based products, as well as other foods such as bread, could help reduce the risk of nutrient shortfalls.

Using data from the National Diet and Nutrition Survey covering more than 3,500 people aged 18 months to 100 years, the team modelled the effect of replacing dairy with plant-based alternatives on four micronutrients commonly supplied by dairy: iodine, calcium, riboflavin and vitamin B12.

The results showed that even small reductions in dairy intake, replaced with plant-based alternatives, led to clear drops in all four nutrients. Iodine was especially affected.

Under current market fortification levels, replacing just 20% to 35% of dairy products with plant-based alternatives increased iodine inadequacy among adolescent females from 54% to 65%, and from 32% to 42% among women aged 19 to 49.

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With full replacement, iodine inadequacy rose to 80% among adolescent females and 72% among adolescent males.

The researchers said the findings suggest current voluntary fortification practices are not enough to support a healthy and fair move toward Net Zero and EAT-Lancet dietary goals.

They also looked at whether mandatory fortification of plant-based dairy alternatives could help prevent deficiencies.

That approach stopped micronutrient intake from falling when dairy was replaced, although iodine inadequacy still affected 59% of adolescent females. Adding iodine-fortified bread improved intake further and reduced inadequacy among adolescent females to 37%.

According to the researchers, the strongest way to reduce iodine inadequacy is to combine mandatory fortification of plant-based dairy alternatives with iodine-fortified bread.

Dr Katie Nicol of the University of Surrey said: “Nutrition policy must evolve alongside environmental targets, but moves toward more sustainable diets should not come at the expense of public health. Food fortification is one way this could be achieved, but government policy is needed to make it happen.”

Dr Sarah Bath, Associate Professor in Public Health Nutrition, said the UK is particularly exposed to iodine insufficiency because it lacks an iodine fortification policy.

“People may also be unaware of the importance of iodine, which is needed to make thyroid hormones that regulate our metabolism and support healthy growth and brain development.”

Dr Anne Nugent from the School of Biological Sciences at Queen’s University Belfast said that because the nutrient content of supermarket dairy alternatives can vary, the research also used a condition to ensure each dairy alternative identified had an equal chance of selection.