A sustainable mixed diet for children without compromising nutritional needs: The vitamin B12 issue.

Global climate change requires a paradigm change in diets, especially in affluent countries, with a reduction of animal-based food, including children. This will have direct consequences for Vitamin B12 supply as animal-based foods are the only food source. We examined these potential consequences using the German food based dietary guidelines for infants, children, and adults in Germany as the basis for the model calculation. The guidelines for 4 representative age groups were examined, representing exclusive milk feeding (2 months), complementary feeding (8 months), and mixed family diet (children: 4-6 years, adolescents: 11-14 years). For each age group (except 2 months), the contribution of animal-based food groups (milk/dairy, meat, fish, eggs) to the total daily intake of vitamin B12 was calculated based on 7-day menus with recipes for all meals. This allowed us to assess the potential Vitamin B12 deficits due to food group exclusion. Even in the guidelines diets, including exclusive breastfeeding, the vitamin B12 intakes just reached the reference values in all age groups. In infants on complementary feeding and also later in children and adolescents, cow's milk was by far the most important source of vitamin B12. Among the other animal-based foods, meat (16.9%-23.0%) ranked first, followed by fish (11.0%-16.5%), and eggs (8.1%). In our analysis of the German food-based guidelines for infant, child, and adolescent diets, the increased planetary health due to reduction of milk intake turned out severely to compromise vitamin B12 intake. In children, a reduction in the consumption of animal foods to improve the health of the planet must be weighed against the risk of inadequate intake of individual nutrients.