Measures playing significant role in the prevention of malignant tumors refer to the use of phytochemicals, minerals, vitamins and polyunsaturated fatty acids of the omega-3 in the diet. The protective role of omega-3 polyunsaturated fatty acids rests upon their ability to inhibit cell proliferation, induce apoptosis, promote and differentiate cells. Moreover, a whole-grain diet is a protective agent against certain cancers, especially colorectal cancer and breast cancer. The number and multiplicity of factors affecting the occurrence of malignant tumors indicates a permanent need to control the risk of cancer.

Key words: breast cancer, nutrition, prevention.