Molecular basis of phytosterols diet complementation in the context of cancer morbidity and treatment

Phytosterols used to be associated mainly with a hypolipemic mechanism of action. However, it is suggested that a high phytosterol content in the diet can also reduce the frequency of numerous cancers. The most common environ-mental phytosterols are b-sitos-terol, campesterol and stigmasterol. Their structural similarity to cholesterol also results in similar metabolic fates of those compounds in humans, but phytosterols are absorbed much less efficiently from the digestive system. The biological effect of phytosterols administration is diverse and depends on many factors. They can show anti-atherogenic activity due to cholesterol level decrease in blood, but also anti-inflammatory and anti-allergic properties. Phytosterol oxy-derivatives show different action revealing cytotoxic, mutagenic and cancerogenic properties. Phytosterols and their oxy-derivatives may have a positive influence on the human body, causing cancer cell proliferation and metastasis inhibition or inducing their apoptosis and activating the immunological system. They can also inhibit glycoprotein-P activity, which is responsible for the multidrug resistance phenomenon. However, it was also revealed that some phytosterols and oxy-phytosterols can show cytotoxic properties in normal human cells.