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The intake of fruits and vegetables is associated with reduced incidence of many chronic diseases. These foods contain phytochemicals that often possess antioxidant and free radical scavenging capacity and show anti-inflammatory action, which are also the basis of other bioactivities and health benefits, such as anticancer, anti-aging, and protective action for cardiovascular diseases, diabetes mellitus, obesity and neurodegenerative disorders. Many factors can be included in the etiopathogenesis of all of these multifactorial diseases that involve oxidative stress, inflammation and/or cell death processes, oxysterols, i.e. cholesterol oxidation products (COPs) as well as phytosterol oxidation products (POPs), among others. These oxidized lipids result from either spontaneous and/or enzymatic oxidation of cholesterol/phytosterols on the steroid nucleus or on the side chain and their critical roles in the pathophysiology of the abovementioned diseases has become increasingly evident. In this context, many studies investigated the potential of dietary phytochemicals (polyphenols, carotenoids and vitamins C and E, among others) to protect against oxysterol toxicity in various cell models mimicking pathophysiological conditions. This review, summarizing the mechanisms involved in the chemopreventive effect of phytochemicals against the injury by oxysterols may constitute a step forward to consider the importance of preventive strategies on a nutritional point of view to decrease the burden of many age-related chronic diseases. [ABSTRACT FROM AUTHOR]

Pathological accumulation of 27-carbon intermediates or end-products of cholesterol metabolism, named oxysterols, may contribute to the onset and especially to the development of major chronic diseases in which inflammation, but also oxidative damage and to a certain extent cell death, are hallmarks and primary mechanisms of progression. Indeed, certain oxysterols exercise strong pro-oxidant and pro-inflammatory effects at concentrations detectable in the lesions typical of atherosclerosis, neurodegenerative diseases, inflammatory bowel diseases, age-related macular degeneration, and other pathological conditions characterized by altered cholesterol uptake and/or metabolism.

For years food consumers have been warned that a cholesterol-rich diet may result in atherosclerosis. It is also well known that consumption of large amounts of phytosterols decreases concentration of low-density lipoproteins (LDLs) in blood (LDLs are regarded a key risk factor in development of cardiovascular diseases). However, no scientific evidence has unambiguously proved any direct connection between amount of consumed cholesterol and LDL level in blood. On the other hand, concentration of cholesterol oxidation products, oxysterols, seems to be indeed relevant; for example, they significantly impact appearance of atherosclerotic lesions (plaques). Phytosterols (like sitosterol or campasterol) decrease LDL level in blood, but on the other hand products of their oxidation are toxic. Therefore, it is worth to know influence of phytosterols on living organisms, processes which lead to their formation, and their levels in popular foodstuffs. This paper is an attempt to review literature data on the above aspects, as well as on impact on living organisms of oxidation products of popular sterols. [ABSTRACT FROM AUTHOR]