Shifting to Plant-Based Protein Diets Alters Nutrient Adequacy Across Age Groups: A Dutch Dietary Modeling Study

Background: Shifting toward more plant-based diets is promoted for health, environmental, and ethical reasons. However, the nutritional consequences of reducing animal-based foods, particularly across age groups with specific dietary needs, remain insufficiently understood. Methods: In this simulation study, we used dietary intake data from 3570 participants in the Dutch National Food Consumption Survey (2019–2021) to evaluate how replacing animal-based foods with plant-based alternatives affects the intake of protein, essential amino acids (EAAs), vitamins, and minerals across different age groups. Two substitution scenarios were modeled: a nutritionally conscious and a less conscious plant-based dietary pattern. Results: Total protein intake decreased in both scenarios, with the strongest reductions observed in elderly individuals (71–79 years). Vitamin intake, particularly B vitamins and vitamin A, declined in most age groups, and vitamin D remained chronically low. Mineral intake also decreased, notably for calcium, iron, iodine, selenium, and zinc, especially among women and adolescents. Conclusions: These results underscore the importance of dietary planning and targeted fortification when promoting plant-based eating patterns. Future research should refine bioavailability estimates and evaluate the long-term health effects of such dietary transitions across life stages.