# Association between Mediterranean Dietary Pattern and Breakfast Quality with Physical Fitness in School Children: The HIIT Project

PMID: 33919630
Journal: Nutrients
Published: 2021 Apr 16
Authors: Cadenas-Sanchez C, Medrano M, Arenaza L, Amasene M, Osés M, Labayen I

## Question

Are Mediterranean diet adherence and breakfast quality associated with physical fitness in 9- to 10-year-old school children?

## Summary

In a baseline cross-sectional analysis of 175 Spanish school children from the HIIT Project, children with higher Mediterranean diet adherence had better cardiorespiratory fitness, standing broad jump, and speed-agility before accounting for physical activity. Those associations disappeared after adjustment for accelerometer-measured activity, and breakfast quality was not associated with fitness.

## Population

- Spanish school children from the HIIT Project baseline cohort.
- Sample size: 175
- Age: 9.7 +/- 0.3 years
- Sex: 50.3% girls
- Fitness level: General school-child cohort
- Health status: No disorders hampering exercise or evaluation

## Methodology

- Cross-sectional baseline analysis from the HIIT Project randomized trial
- Baseline assessment only
- Two schools in Navarra, Spain

## Protocol

- No exercise intervention.
- Program length: Baseline observational analysis.

## Outcomes

### MDP fitness
Status: mixed
Higher Mediterranean diet adherence related to higher fitness before activity adjustment, but not after.

Age/sex model beta >=0.189, p<=0.02; after MVPA adjustment all p>0.05

### Breakfast
Status: no clear change
Breakfast quality was not associated with fitness.

All p>0.05

### Fitness groups
Status: mixed
High MDP children had higher shuttle-run laps, jump distance, and agility before activity adjustment.

CRF p=0.041; standing broad jump p=0.016; speed-agility p=0.023

## Practical Insights

- When discussing children's fitness, physical activity may explain apparent diet-fitness associations.
- Do not infer that breakfast quality improves fitness from this analysis.

## Limitations

- Cross-sectional design prevents causal inference.
- Breakfast quality was based on one 24-hour recall.
- No HIIT intervention outcomes were reported.

## Safety And Adherence

- No adverse events were reported.
- This was a baseline observational analysis, not a HIIT intervention study.
- Children with psychological or physical disorders hampering exercise or evaluation were excluded.

## Original Sources

- [PubMed](https://pubmed.ncbi.nlm.nih.gov/33919630/) (pubmed)
- [DOI](https://doi.org/10.3390/nu13041353) (doi)
- [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8072945/) (full text)

## Agent Guidance

Preserve the paper-level scope of this note. Do not generalize beyond the population, protocol, measured outcomes, and limitations above.