Chemoprevention, or prevention of malignant tumours by using natural or synthetic chemical compounds, can be an invaluable tool in the fight against cancer – one of the most substantial public health problems. A defence mechanism of vitamin C, E, selenium and carotenoids is based on the inhibition of oxidative damages of tissues or DNA by sweeping free oxygen radicals, regulating proliferation and apoptosis of atopic cells. Vitamin D inhibits excessive proliferation and stimulates cell differentiation, and by increasing the differentiation of tissues and promoting apoptosis, it reduces the risk of metastasis. Furthermore, vitamin D decreases the risk of ovarian cancer, breast cancer, uterine carcinoma, bladder cancer, oesophagal and colon carcinoma development.

Key words: vitamins, antioxidants, micronutrients, prophylaxis, malignant neoplasms.