Dietary cholesterol oxidation products: Perspectives linking food processing and storage with health implications

Abstract

Dietary cholesterol oxidation products (COPs) are heterogeneous compounds formed during the processing and storage of cholesterol‐rich foods, such as seafood, meat, eggs, and dairy products. With the increased intake of COPs‐rich foods, the concern about health implications of dietary COPs is rising. Dietary COPs may exert deleterious effects on human health to induce several inflammatory diseases including atherosclerosis, neurodegenerative diseases, and inflammatory bowel diseases. Thus, knowledge regarding the effects of processing and storage conditions leading to formation of COPs is needed to reduce the levels of COPs in foods. Efficient methodologies to determine COPs in foods are also essential. More importantly, the biological roles of dietary COPs in human health and effects of phytochemicals on dietary COPs‐induced diseases need to be established. This review summarizes the recent information on dietary COPs including their formation in foods during their processing and storage, analytical methods of determination of COPs, metabolic fate, implications for human health, and beneficial interventions by phytochemicals. The formation of COPs is largely dependent on the heating temperature, storage time, and food matrices. Alteration of food processing and storage conditions is one of the potent strategies to restrict hazardous dietary COPs from forming, including maintaining relatively low temperatures, shorter processing or storage time, and the appropriate addition of antioxidants. Once absorbed into the circulation, dietary COPs can contribute to the progression of several inflammatory diseases, where the absorbed dietary COPs may induce inflammation, apoptosis, and autophagy in cells in the target organs or tissues. Improved intake of phytochemicals may be an effective strategy to reduce the hazardous effects of dietary COPs.

The Impacts of Cholesterol, Oxysterols, and Cholesterol Lowering Dietary Compounds on the Immune System

“…Dietary oxysterol is produced by the oxidation of cholesterol with oxygen and the reactive oxygen species (ROS) during cooking and storage of foods. Several studies showed that oxysterols are increased under conditions of microwave cooking or long-term frozen storage [ 26 , 27 , 28 , 29 ]. The main sources of dietary oxysterols are processed or stored in eggs and dairy products, and other cholesterol rich foods.…”

“…Cholesterol oxidation products can already be detected in raw meat (2–11 mg/kg fat), and the concentrations rise during thermal processing (3.4–35 mg/kg fat). Egg yolk powders (441–714 mg/kg fat) and butter, as well as butter oil (13.7–27.3 mg/kg fat), are major dietary sources of cholesterol oxidation products [ 26 , 27 , 28 , 29 ]. The most commonly detected individual oxysterols in foods are C7 cholesterol oxides: 7α-hydroxycholesterol (7α-HC), 7β-hydroxycholesterol (7β-HC), and the oxidation product of both, 7-ketocholesterol (7-KC) ( Figure 3 ).…”

“…In addition to the C7 cholesterol oxides, epoxidation products, 5α,6α-epoxycholesterol (5α,6α-EPOX) and 5β,6β-epoxycholesterol (5β,6β-EPOX), are generated by non-enzymatic oxidation [ 30 ]. These epoxides are less important in milk, but comparatively abundant in egg fat, where they can be the main species of cholesterol oxidation products [ 29 ]. Storage mainly leads to an increase in sterol oxidation.…”

Dietary Oxidized Cholesterol Aggravates Chemically Induced Murine Colon Inflammation and Alters Gut Microbial Ecology

“…These oxygen groups make oxidized cholesterol more polar and easier to diffuse into the cell membrane. , Previous in vitro experiments have found that oxidized cholesterols are more reactive than cholesterol itself in promoting the inflammation, oxidative stress, and programmed cell death . Meanwhile, the oxidized cholesterol-enriched diet has been blamed to be partially accountable for atherosclerosis and neurodegenerative diseases . Dietary oxidized cholesterols have been shown to exacerbate the inflammation via increasing the concentrations of IL-6 and tumor necrosis factor alpha (TNF-α) .…”

“…17 Meanwhile, the oxidized cholesterol-enriched diet has been blamed to be partially accountable for atherosclerosis and neurodegenerative diseases. 18 Dietary oxidized cholesterols have been shown to exacerbate the inflammation via increasing the concentrations of IL-6 and tumor necrosis factor alpha (TNF-α). 19 that these pro-inflammatory cytokines are involved in the progress of IBDs.…”