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.
Keywords: blood pressure; child; kidney; protein.