Table 1.

General structure of the questionnaire

Section 1 – Information about sociodemographic and physical characteristics, lifestyle, and health status

Self-reported: age (years), height (cm), weight (kg)

Questions (closed-ended format) relative to:

Gender (M/F); education (less than high school, high school, degree); income (high, average, low); smoking status (current smoker, former smoker, non-smoker); self-perceived health status (good, fair, poor) and stress level (none, low, high); sports participation (gymnastics, swimming, running, tennis, cycling, etc.) (yes/no); and sports frequency (1–2 times/week, ≥3 times/week)

Questions (open-ended format) relative to:

Occupation (public/private employee, merchant/craftsman, farmer/worker, manager/professional, housewife/pensioner unemployed, student, other occupations); medical conditions (hypertension, hypercholesterolaemia, diabetes, osteoporosis, joint diseases, CVD, anxiety/depression, other conditions); intake of medicines (for hypertension, hypercholesterolaemia, diabetes, osteoporosis, joint diseases, CVD, anxiety/depression, other conditions)

Section 2 – Information regarding dietary habits (FFQ)

Questions (closed-ended format) relative to:

Frequency of consumption (times/d, times/week, times/month, never/occasionally) of eleven food groups: Pasta or rice; Bread, bread-sticks, crackers; Baked products (biscuits, snacks, cakes, pizza, etc.); Meat (fresh, preserved); Fish (fresh, frozen, preserved); Eggs; Pulses (fresh, dried, preserved); Milk or Yoghurt; Cheese; Vegetables (raw, cooked, salad); and Fruit

Alcohol consumption (wine, beer, spirits, etc.) (glasses/d, glasses/week, glasses/month, never/occasionally)

Regular use of wholemeal cereal-based foods (yes/no)

Section 3 – Information regarding the use of food supplements

Questions (closed-ended format) relative to:

Consumption of food supplements during the last 2 years (yes/no)

Consumption of eight categories of food supplements (products containing vitamins and minerals, dietary fibre, fatty acids, antioxidants, probiotics, botanicals and botanical extracts, products targeted to sportsmen or postmenopausal women) (yes/no) with the possibility to enter the name of the product

Section 4 – Information regarding user's behaviour

Questions (closed-ended format) relative to:

Frequency of use (regular, occasional); use in specific physiological conditions (pregnancy/lactation, convalescence, weight-loss diet); purpose of taking food supplements (improvement of health status/well-being, insufficient ingestion with diet, alternative to medicines, improvement of physical performance, delaying ageing); recommendation for use (self-prescription, medical doctor including specialists, pharmacist, friends/relatives, media/press/advertising); self-perceived benefit (great, some, little, none, I don't know); compliance with directions for use (yes/no); awareness of contraindications (yes/no); occurrence of adverse effects (yes/no); and reporting of use and any adverse effects to family doctor (yes/no)