Organic Diet Intervention in Primary School Children

The study aims to evaluate the hypothesized benefits of a systematic organic diet for children, over those of a conventional diet. The specific objectives of this study are to: i) Demonstrate the decreased body burden of pesticides for those children consuming an organic diet, and ii) Evaluate the effects in specific biomarkers of inflammation and oxidative stress in children systematically consuming an organic diet.

A single-blinded, randomised 2 x 2 cross-over study is conducted to evaluate the effect of a 40-day organic diet compared to a 40-day conventional diet on biomarkers of exposure (pesticides metabolites) and biomarkers of effect (oxidative stress/inflammation markers) in children. The study is approved by the Cyprus National Bioethics Committee (ΕΕΒΚ/ΕΠ/2016/25) and the Cyprus Ministry of Education and Culture (7.15.06.15/2). Written informed consent for children to participate in the study is obtained from children's parents or legal guardians. Study participants are recruited from public primary schools in Limassol, Cyprus following communication with the school's headmaster. Each school that participates in the study is randomized to one of the two study arms; conventional-organic or organic-conventional. Participants' blinding is not possible since children know which diet they have at each phase. However, all documents and urine containers are coded, so that researchers are blinded to subjects' identity and group allocation.

Participants provide 6 first morning urine samples during the duration of the study; 1 baseline sample, 2 samples in the conventional phase and 3 samples in the organic phase. Anthropometric measurements (weight, height, waist circumference) are taken at the beginning and end of the study by trained researchers at the school area. A baseline questionnaire is administered to parents at the beginning of the study through a telephone interview to collect information on demographic characteristics, pesticide use at household and children's activities. A food frequency questionnaire is administered to parents at the end of the conventional phase through a telephone interview to collect information about the food habits of the children during the 40-day conventional period. A food diary is given to parents at the beginning of the study and parents use it during the organic phase, to collect information about the compliance of the children to the organic dietary menu, the children's health status and the pesticide use at home.

In order to encourage adherence to the organic diet menu, an event is organised during the organic phase of both groups, with activities for children and free sampling of organic food products.

Descriptive statistics are used to summarize the demographic characteristics for participating children. Categorical variables are described as sample size and percentages, normally-distributed continuous variables as mean±SD and non-normal continuous variables as median and interquartile range (Q1-Q3) or the appropriate transformation is conducted, such as the log transformation. For testing whether characteristics of interest are different among groups the Student's t-test are utilized for continuous normally distributed variables and the chi-square test for categorical characteristics. For continuous data that are not normally distributed, the Wilcoxon non-parametric analysis is used instead or a transformation of the data is conducted first in order to meet the normality criterion.

Linear mixed-effects models are used to account for the correlation among repeat urine samples collected from the same child and determine whether mean pesticide metabolite and biomarkers concentrations differ between the organic phase and the conventional phase.

Eligibility Criteria:
Inclusion Criteria:

* Healthy children aged 10-12 years, residing in Cyprus over the last five years who consume primarily (\> 80%) conventional food (non-organic).

Exclusion Criteria:

* Children with chronic conditions (e.g. diabetes, asthma) or allergies in food (e.g. gluten, lactose tolerance)