Dietary Intake, Nutritional Adequacy, and Food Sources of Protein and Relationships with Personal and Family Factors in Spanish Children Aged One to <10 Years: Findings of the EsNuPI Study †

Diet in the first years of life is an important factor in growth and development. Dietary protein is a critical macronutrient that provides both essential and nonessential amino acids required for sustaining all body functions and procedures, providing the structural basis to maintain life and healthy development and growth in children. In this study, our aim was to describe the total protein intake, type and food sources of protein, the adequacy to the Population Reference Intake (PRI) for protein by the European Food Safety Authority (EFSA), and the Recommended Dietary Allowance (RDA) by the Institute of Medicine (IoM). Furthermore, we analyzed whether the consumption of dairy products (including regular milk, dairy products, or adapted milk formulas) is associated with nutrient adequacy and the contribution of protein to diet and whole dietary profile in the two cohorts of the EsNuPI (in English, Nutritional Study in the Spanish Pediatric Population) study; one cohort was representative of the Spanish population from one to <10 years old (n = 707) (Spanish reference cohort, SRS) who reported consuming all kinds of milk and one was a cohort of the same age who reported consuming adapted milk over the last year (including follow-on formula, growing up milk, toddler’s milk, and enriched and fortified milks) (n = 741) (adapted milk consumers cohort, AMS). The children of both cohorts had a high contribution from protein to total energy intake (16.79% SRS and 15.63% AMS) and a high total protein intake (60.89 g/day SRS and 53.43 g/day AMS). We observed that protein intake in Spanish children aged one to <10 years old was above the European and international recommendations, as well as the recommended percentages for energy intakes. The main protein sources were milk and dairy products (28% SRS and 29% AMS) and meat and meat products (27% SRS and 26% AMS), followed by cereals (16% SRS and 15% AMS), fish and shellfish (8% in both cohorts), eggs (5% SRS and 6% AMS), and legumes (4% in both cohorts). In our study population, protein intake was mainly from an animal origin (meat and meat products, milk and dairy products, fish and shellfish, and eggs) rather than from a plant origin (cereals and legumes). Future studies should investigate the long-term effect of dietary protein in early childhood on growth and body composition, and whether high protein intake affects health later in life.