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Plant protein switch impacts nutrient levels

Article-Plant protein switch impacts nutrient levels

When partially substituting animal-source protein with plant-source protein across a 12-week intervention, vitamin B-12 and iodine were significantly reduced and therefore among the most essential nutrients to recover.

Reducing consumption of animal-derived meat and dairy has the potential to decrease the environmental impact of food production. While there are increasingly high percentages of flexitarian consumers who don’t eat meat on a regular basis, a worldwide trend of an expanding appetite for meat still exists.1 With the potential transition of many individuals towards a flexitarian lifestyle, it is important to consider how this shift impacts intake of various nutrients, given potential differences in bioavailability and nutrient density. 

According to a recent study published in the European Journal of Nutrition (DOI: 10.1007/s00394-021-02729-3), intake and status of vitamin B-12 and iodine were significantly reduced when animal protein diets were partially replaced with plant protein alternatives. 

The study investigated the extent to which plant proteins could replace animal proteins in flexitarian diets to achieve health advantages while ensuring adequate intake of essential vitamins and minerals. The research included 146 healthy participants who were 20-69 years old with a BMI between 18.5 and 35.0 kg/m2. They were divided into one of three groups: Animal (n=46), a diet containing 70% animal and 30% plant protein; 50/50 (n=46), a diet containing 50% animal and 50% plant protein; or Plant (n=44), a diet containing 30% animal and 70% plant protein. Overall, 136 participants completed the study. The randomized controlled trial examined intake of folate, vitamin B-12, iron, zinc, and iodine and nutritional status biomarkers after 12 weeks of dietary intervention. 

The shift from animal to plant proteins yielded significantly lower intakes and statuses of vitamin B-12 and iodine. Despite the Plant group's greater iron and folate intakes than the Animal group, there were no significant variations in the biomarkers. Zinc was lowest in the Plant group, although it was above the recommended intake across all groups.2 In reference to vitamin B-12 and iodine, the researchers conclude that “the adequate intake of these nutrients needs to be ensured when recommending more plant-based diets on a population level.” 




1. Dagevos H. Flexibility in the frequency of meat consumption–empirical evidence from the Netherlands. EuroChoices. 2014 Aug;13(2):40-5. 

2. Nordic Nutrition Recommendations 2012 : Integrating nutrition and physical activity [Internet]. 5th ed. Copenhagen: Nordisk Ministerråd; 2014. 627 p. (Nord). Available from: