Effect of Protein Intake Early in Life on Kidney Volume and Blood Pressure at 11 Years of Age

High protein intake has been associated with kidney hypertrophy, which is usually reversible; however, when it occurs early in life, it could lead to cell programming with a long-lasting effect. This study aimed to assess whether higher protein ingestion early in life has a persistent effect on kidney volume at 11 years of age, as well as its influence on blood pressure. This is a secondary analysis of a randomized control trial that compared the growth of infants fed with a higher-protein formula versus those fed with a lower-protein formula, with a control group of breastfed infants. Renal ultrasound and anthropometric measurements were assessed at 6 months and 11 years of age. At 11 years, urinary protein, albumin and creatinine, and blood pressure were measured in 232 children. Feeding with a higher-protein formula was associated with a larger kidney volume (β = 8.71, 95%CI 0.09–17.33, p = 0.048) and higher systolic blood pressure (β = 3.43, 95%CI 0.78–6.08, p = 0.011) at 11 years of age. Microalbuminuria was detected in 7% of the patients, with no differences among groups (p = 0.56). The effect of increased protein ingestion early in life may condition kidney volume and blood pressure in later childhood.