The aim of the study is to validate short questionnaires for assessing dietary intake of selected food components, with a focus on dietary fibre and iron. Two internationally developed short questionnaires (FiberScreen [for dietary fibre] and IRONQ-FFQ [for iron]) were adapted to the Slovenian context and will be compared with the standard 24-hour dietary recall method.

Based on previous research conducted in Slovenia and across Europe, it can be concluded that notable proportion of the Slovenian population does not meet the recommended intake of dietary fibre. At the same time, there are important population groups at increased risk of inadequate iron intake, particularly women of reproductive age. Both nutrients have significant implications for health and represent an important public health challenge that requires appropriate monitoring of dietary intake at the population level.

With the aim of providing a simple and reliable assessment of dietary fibre and iron intake in research, clinical, and public health settings, two short questionnaires adapted to the Slovenian context have been developed. The questionnaire for assessing dietary fibre intake (KV-PV) is based on the FiberScreen questionnaire developed by Dutch researchers and was adapted to the Slovenian dietary pattern using data from the SI.Menu study. The questionnaire for assessing iron intake (KV-Fe) is based on the validated IRONQ-FFQ and adapted for the Slovenian population.

Despite the content adaptation of both questionnaires to the Slovenian context, further validation is required before their practical application, in order to assess the reliability and usability of these tools for evaluating dietary fibre and iron intake in Slovenia.

The objectives of the project are to:

Determine dietary fibre intake as assessed by the KV-PV questionnaire. Determine iron intake as assessed by the KV-Fe questionnaire. Determine dietary fibre intake using a 5-day dietary record. Determine iron intake using a 5-day dietary record. Compare dietary fibre intake assessed by the KV-PV questionnaire with the 5-day dietary record and evaluate the reliability of the KV-PV.

Compare iron intake assessed by the KV-Fe questionnaire with the 5-day dietary record and evaluate the reliability of the KV-Fe.

Compare the results of two KV-PV questionnaires completed with a 6-week interval.

Compare the results of two KV-Fe questionnaires completed with a 6-week interval.

Examine potential correlations between the results of the tested questionnaires and selected biochemical indicators in participants who voluntarily opt for blood sampling.

Inclusion criteria:

• Willingness to participate in the study.
• Signed Statement of Informed and Voluntary Consent to Participate in the Study.
• Age between 18 and 65 years at the time of enrolment in the study.
• Willingness to comply with all study procedures and to keep a dietary record in accordance with the provided instructions.

Exclusion criteria:

• Pregnancy or breastfeeding.
• Specific dietary practices followed by a small proportion of the population (veganism, LCHF, calorie-restricted diets; note: vegetarians are not excluded).
• Diets prescribed by medical professionals.
• Mental incapacity that prevents adequate understanding or participation.

Reasons for excluding a participant during the study:

• Inability to participate in the study
• Wishes to discontinue participation
• Incomplete data provided

About 50 subjects, aged 18-65 years, with expected drop-out rate about 10%. Invitations through institute web page and social media.