Experts warn against unsupervised vitamin use and dietary trends in oncology

A new study coordinated by Dr. Salvatore Cortellino and Professor Antonio Giordano, President of the Sbarro Health Research Organization (SHRO) and molecular oncologist at Temple University and the University of Siena, offers a critical assessment of vitamin supplementation and popular dietary trends in the context of cancer prevention and treatment. Published in Expert Review of Anticancer Therapy, the review cautions against the widespread belief, promoted by mass media and the wellness industry, that over-the-counter vitamins and fad diets can independently extend life expectancy or improve cancer outcomes.This work has been significantly enhanced by the esteemed contributions of Teresa Esposito, MD, Department of Clinical Dietetics and Metabolic Diseases, Cavalier Raffaele Apicella Hospital, ASL Napoli 3 Sud, Naples, Italy, and Francesca Pentimalli, PhD, Department of Medicine and Surgery, LUM University 'Giuseppe De Gennaro', Bari, Italy.

The analysis reveals that while vitamin deficiencies are frequently observed in cancer patients and may contribute to increased cancer risk, supplementation through pharmaceutical-grade multivitamins has not demonstrated clear clinical benefit. Instead, the authors underscore the importance of a balanced diet, particularly the Mediterranean diet, as the most reliable strategy for maintaining adequate micronutrient levels.

Crucially, the review raises concerns about hypervitaminosis, a condition resulting from excessive intake of vitamins without medical supervision. In oncological patients, such an imbalance could paradoxically stimulate tumor progression. Likewise, dietary trends such as ketogenic regimens, intermittent fasting, or even strict veganism, while supported by preclinical models, lack robust evidence of effectiveness in human cancer therapy. In some cases, these restrictive dietary practices may exacerbate cancer-related cachexia or result in malnutrition, particularly in frail or elderly patients.

Our findings suggest that following dietary fashions without clinical guidance can be not only ineffective but potentially harmful for cancer patients. There is no substitute for evidence-based medicine and a personalized approach to nutrition."

Professor Antonio Giordano, President, Sbarro Health Research Organization

The authors advocate for medical consultation before initiating any significant dietary change, especially in the presence of risk factors or active disease. Nutritional decisions whether related to supplements or entire eating plans should be made in collaboration with qualified healthcare professionals such as physicians, clinical nutritionists, or dietitians. The study concludes by reaffirming that health is best preserved through physiological balance, achieved by maintaining adequate caloric intake, adhering to a varied and wholesome diet, and engaging in regular physical activity in accordance with individual needs. These principles, rooted in the European Code Against Cancer and the Mediterranean lifestyle, remain the cornerstone of cancer prevention and patient wellbeing.