Dietary Quality and Nutritional Adequacy Among Vegetarians Attending the European Institute of Oncology

150 vegan, vegetarian, semi-vegetarian women (18-64 years) will be recruited among patients attending the European Institute of Oncology for prevention visits or oncological follow-up. The study will include a baseline visit and a 3-month follow-up visit, with an interim telephone contact.

At baseline, nutritional adequacy and diet quality will be assessed, followed by a personalized nutritional counselling aimed at improving dietary variety, ensuring adequate nutrient intake, and promoting an active lifestyle. The intervention will be based on a vegetarian adaptation of the Healthy Eating Plate and aligned with national and international guidelines (CREA,2019; WCRF, 2018).

During study visits, anthropometric measurements (height, weight, waist and hip circumferences), body composition (BIVA), and blood samples will be collected. Dietary intake will be evaluated via a 3-day food records. Validated questionnaires will be administered to assess physical activity (IPAQ-SF), adherence to the Mediterranean diet (QueMD), and quality of life (VEGQOL). Additionally, vegetarian diet quality and lifestyle will be evaluated using the Vegetarian Lifestyle Index.

Nutritional adequacy will be determined by comparing dietary intake and blood biomarkers with Italian Dietary Reference Values (DRVs; SINU 2024).

Inclusion criteria

• pre or post-menopausal women, aged between 18 and 64;
• healthy participants or high-risk cancer patients or patients with previous diagnosis of neoplasia
• self-identifying as vegan (defined as excluding all animal products), or vegetarian (defined as excluding all animal products besides eggs and/or dairy) or semi-vegetarian (defined as excluding no animal products but limiting meat to < 1× per week);
• ability to understand and the willingness to sign a written informed consent document;

Exclusion criteria

• any condition which, in the opinion of the investigator, may impede testing of the study hypothesis or make it unsafe to engage in the study (e.g., ulcerative colitis, Crohn's disease etc.);
• any diagnosis of invasive neoplasia, within the previous 1 years, except non-melanoma skin cancer;
• currently receiving chemotherapy, radiation, or immunotherapy as cancer treatment;
• patients dependent on enteral or parental nutrition;
• pregnancy or lactation;