The aim of the study is to investigate the dietary habits of women of reproductive age (20-49 years). We aim to obtain epidemiological data on the intake and adequacy of key macronutrients and micronutrients, as well as to explore associations with various health indicators. Additionally, we will focus on the nutritional status of subgroups with specific dietary practices, such as vegetarians and vegans.

Key scientific challenges addressed in this study are to investigate the dietary habits and nutritional status of women of reproductive age, to provide epidemiological data on the nutrient intakes in this group (including intakes of key micronutrients) and investigate their relationship with various markers of health. We will evaluate dietary behaviours and special dietary practices among women of reproductive age in Slovenia, through age-representative sampling approach. We will also detailly assess dietary supplementation practices in this population group. Dietary intakes of macro and key micronutrients and nutritional/health status will be evaluated using a cross-sectional epidemiological study.

Further we will investigate links between dietary behaviours with nutritional and health status in order to identify increased nutritional and health risk, as well as potential benefits of different dietary practices. We will particularly focus into following sub-groups of women: omnivorous women, that do not follow any special diet, women that follow vegetarian diet, and women that follow vegan diet. In order to investigate the status of the key micronutrients, standard blood biomarkers will be used. This will allow us to determine nutritional status for iron, folate, vitamin B12 and vitamin D. Body composition will be estimated using bioelectrical impedance spectroscopy (BIS). Other measurements of health-related parameters will include tissue protein density using ultrasonography.

Study results will give insights into the nutritional status in general group of women of reproductive age and enable us to identify links between dietary behaviours with nutritional as well as health status. Through that approach we will be able to identify potential risk for deficiencies of nutrients in studied population group.

Applying a highly multidisciplinary approach and building on previous research we will address the following:

• evaluate dietary behaviours of women of reproductive age (20-49 years) through representative sampling approach. This will enable identification of diet related risks in this group.
• determine dietary supplementation practices of women of reproductive age (20-49 years). This will allow us to better estimate intakes of specific nutrients, as supplements can be important dietary source of nutrients.
• investigate nutritional status of women of reproductive age (20-49 years) in Slovenia with a combination of validated standard dietary assessment methods and blood biomarkers. This will enable also insights in nutritional status for key micronutrients, including iron, folate, vitamin B12 and vitamin D.
• investigate links between dietary behaviours with nutritional/health status, providing information about sub-populations with higher health risks. To enable this, population of omnivorous subjects will be compared with those on vegetarian and vegan diet.

Inclusion criteria:

• Age: 20 to 49 years
• Gender: female
• Agrees to participate in the study (has signed a consent form)

Exclusion criteria:

• Menopause (absence of menstruation for at least 12 months, unless the absence is due to hormonal contraception) or post-menopause
• Pregnancy

Reasons for excluding a participant during the study:

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

Additional inclusion criteria for including subpopulations in the second part of the study:

Vegetarians:

• Have followed a vegetarian diet for at least 2 years and do not consume meat or fish more than once a month
• Consume eggs and dairy products more than once a month

Vegans:

- Have followed a vegan diet for at least 2 years and do not consume any animal products more than once a month

At least 3,000 women (20-49) from the Central Slovenia will be randomly invited to participate (selection by the Statistical Office of the Republic of Slovenia). We aim for 1,650 responding participants.

In Part 2, we will include 294 participants from Part 1:

• 202 women representative of the study population
• 46 vegetarians and 46 vegans

To ensure enough participants for Part 2, 550 individuals will be invited. They will be selected using stratified random sampling by age. If needed, we will use the snowball method to recruit more vegetarians and vegans.