Preliminary Evidence Supports that Long-Term Consumption of Higher-Protein Breakfast Promotes Higher Expression of Select miRNA Associated with Cardiometabolic Health in Adolescents.

Background: Increased dietary protein at breakfast promotes cardiometabolic health; however, whether these improvements occur at the molecular level is unknown.

Objectives: The objective was to examine whether long-term consumption of breakfast, varying in protein quantity, alters the expression of circulating microRNAs (miRNAs) associated with cardiometabolic health in "breakfast-skipping" adolescents.

Methods: Thirty adolescents (age: 19 ± 1 y; body mass index: 25.4 ± 3 kg/m²) completed a 6-mo tightly controlled breakfast trial in which participants consumed 350 kcal normal-protein (NP, 10 g protein) or higher-protein (HP, 30 g protein) breakfasts or continued to BS for 6 mo. Fasting blood samples were collected at baseline (PRE) and 6 mo (POST) for assessment of 12 a priori circulating plasma miRNA expression levels (real-time quantitative polymerase chain reaction), glucose, insulin, IL-6, and C-reactive protein.

Results: No main effects of group were observed for any miRNAs; however, a time-by-group interaction was detected for the expression of miR-126-3p (P = 0.05). HP breakfast tended to increase miR-126-3p expression throughout the study (POST-PRE, P = 0.09) leading to greater expression at POST compared with BS (P = 0.03), whereas NP breakfast did not. Additionally, several miRNAs predicted fasting concentrations of IL-6: miR-320a-3p, -146a-5p, -150-5p, -423-5p, -122-5p, glucose: miR-24-3p, -126-3p; insulin: miR-24-3p, -126-3p, -15b-5p; insulin sensitivity: miR-24-3p, -126-3p, -199a-5p, -15b-5p; and β-cell function: miR-15b-5p (R² between 0.2 and 0.39; P < 0.05) from PRE and POST samples across groups.

Conclusions: These data support the daily consumption of a HP breakfast to promote cardiometabolic health, potentially through changes in miRNA expression, in a sensitive life-stage where early intervention strategies are critical to reduce the risk of adult-onset chronic disease.

Trial registration number: NCT03146442.