Study: Replacing Dairy Products with Plant-Based Alternatives May Pose Health Risks

In the first study of its kind conducted in the UK, researchers from the University of Surrey, in collaboration with colleagues from Queen's University Belfast, examined how replacing milk, yogurt, and cheese with commercially available plant-based alternatives affects micronutrient intake.

The team used data from the National Diet and Nutrition Survey, collected from 3,500 people aged between 18 months and 100 years, Scientific Russia reports. The researchers then applied a new modeling approach to assess how replacing dairy products with plant-based alternatives would affect intake of four key micronutrients found in dairy products: iodine, calcium, riboflavin, and vitamin B12.

Dr. Katie Nicol, co-author of the study, said: "With the growing need to ensure environmental sustainability, many dietary recommendations focus on plant-based diets and reducing the consumption of animal products. As plant-based alternatives become increasingly popular, we need to know whether they provide an adequate replacement for the micronutrients found in dairy products. This is particularly important for vulnerable population groups, including young children and adolescent girls, who are more likely to have deficiencies in certain micronutrients that can negatively affect their overall health."

The researchers found that even a modest replacement of dairy products with plant-based alternatives resulted in a noticeable reduction in the intake of all four micronutrients, particularly iodine. For example, replacing just 20–35% of dairy products with plant-based alternatives, at current levels of food fortification on the market, increased the prevalence of iodine deficiency among adolescent girls from 54% to 65%, and among women aged 19–49 from 32% to 42%. When dairy products were replaced entirely, iodine deficiency rates rose to 80% among adolescent girls and 72% among adolescent boys.

Dr. Sarah Bath, Associate Professor at the University of Surrey and lead author of the study, said: "The UK is particularly vulnerable to iodine deficiency because it has no policy on iodine fortification of foods, such as universal salt iodization, which is implemented in many other countries."

People may also be unaware of the importance of iodine, which is essential for producing thyroid hormones that regulate metabolism and support healthy growth and brain development. Iodine is particularly important during pregnancy, when the body's requirements increase. In addition, many people do not realize that dairy products are a major source of iodine, while plant-based alternatives contain very little unless they are fortified with the mineral.

The researchers also examined whether mandatory fortification of plant-based milk alternatives with micronutrients could help prevent nutrient deficiencies. They found that such fortification prevented the decline in micronutrient intake associated with replacing dairy products, although iodine intake remained insufficient among 59% of adolescent girls. However, iodine-fortified bread was found to improve iodine intake further, reducing the prevalence of iodine deficiency among adolescent girls to 37%.

The findings suggest that the most effective strategy for reducing iodine deficiency is to combine mandatory iodine fortification of plant-based dairy alternatives with iodine fortification of bread.

Dr. Nicol concluded: "Food policies must evolve alongside environmental goals, but it is important to ensure that the transition to more sustainable diets does not compromise public health. Food fortification is one way to achieve this, but government policies are needed to implement it."