Effects of polar compounds in fried palm oil on liver lipid metabolism in C57 mice

Integrated Metabolomic and Transcriptomic Analyses of Mouse Liver Reveals the In Vivo Toxicity and Mechanisms of Individual and Combined Toxicants Formed in the Thermal Processing of High-Fat Diets

As a part of a continuous 90 day subchronic toxicology study, integrated metabolomic and transcriptomic approaches were applied to assess the metabolic network changes in the livers of Kunming mice exposed to three typical thermally induced food toxicants, including oxidative derivatives of triacylglycerols (ox-TGs), aldehydes, and 3-monochloropropane-1,2-diol esters (3-MCPDE), as well as their mixtures. Results showed lipid metabolic dysregulation through impaired purine metabolism, PPAR signaling, and bile acid metabolism. Ox-TGs emerged as the most hazardous compound, altering over 10 genes/enzymes. 3-MCPDE exhibited gender-specific effects, significantly upregulating fatty acid metabolism and gluconeogenesis genes in males. Interestingly, toxicant mixtures attenuated the adverse metabolic effects caused by individual compounds, demonstrating complex regulatory mechanisms in fatty acid biosynthesis and oxidation. The metabolomic and transcriptomic analyses conducted in this study revealed that combined exposure to multiple toxicants generated during lipid thermal processing may induce more complex toxicity effects than the simple additive effects of individual toxicants. Certain antagonistic effects were observed when comparing individual toxicants to their mixtures, highlighting the need for further mechanistic verifications in this area.

Ninety-Day Subchronic Toxicology of Individual and Combined Toxicants from the Thermal Processing of Lipid-Rich Foods

Oxidative derivatives of triacylglycerols (ox-TGs), aldehydes, and 3-monochloropropane-1,2-diol esters (3-MCPDE) were simultaneously evaluated in a 90-day subchronic study, focusing on biological indicators, biochemical indicators, and serum metabolomics as the first part of integrated toxicity and interactions. After 90 days of feeding Kunming mice, coexposure to combined toxicants significantly inhibited the trend of liver weight gain, reduced the levels of total bilirubin (TBIL) and direct bilirubin (DBIL), and decreased uric acid (UA) compared to individual toxicant exposure. A total of 21 and 31 biomarkers in female and male mice were identified, respectively. Co-exposure to combined toxicants might mitigate the changes in cytidine, CDP, dUMP, and dUDP involved in purine and pyrimidine metabolism caused by a single exposure, but exacerbate the changes in l-tryptophan, 5-hydroxy-l-tryptophan, and 5-hydroxyindoleacetic acid, which are involved in tryptophan metabolism. These results provided new insights into a comprehensive toxicity and interaction evaluation model of multiple combined toxicants in food.

Novel high-oleic oil consumption for cardiometabolic health: a narrative review

Several cardiometabolic disorders are risk factors for cardiovascular diseases (CVDs), and prevention is imperative in reducing the burden of these diseases on the healthcare system. Although novel high-oleic acid oils (HOOs) are now commonly used for high-temperature frying in both foodservice and the manufacture of processed foods, there are still limited data regarding their effects on CVD risk. This narrative review aims to clarify these effects by comparing HOOs with saturated fatty acid (SFA)-rich and polyunsaturated fatty acid (PUFA)-rich oils, first regarding their physicochemical properties and then concerning their effects on CVD risk factors using recent randomized controlled trials (RCTs). Overall, although HOOs are more stable than PUFA-rich oils, they do not have the same high-temperature stability as SFA-rich oils. RCTs demonstrate that HOO consumption improves the plasma lipid profile compared with SFA-rich oils while showing similar effects to those of PUFA-rich oils on CVD risk factors. Finally, the current literature lacks information on the actual consumption of HOOs, their long-term effects on cardiometabolic health, and the impact of prolonged heating of these oils on CVD risk factors. In sum, the short-term intake of HOOs may be beneficial for cardiometabolic health; however, more research is needed.

Dietary oxidized frying oil activates hepatic stellate cells and accelerates the severity of carbon tetrachloride- and thioacetamide-induced liver fibrosis in mice

Deep-frying is a common cooking practice worldwide, and after repeated heating's, the oil undergoes various chemical reactions, including hydrolysis, polymerization, lipid oxidation, and the Maillard reaction. Studies have pointed out that oxidized dietary frying oil may cause teratogenesis in mice and increase cancer and cardiovascular risks. The liver is the main organ involved in dietary nutrient catabolism, detoxification, bile production, and lipid metabolism. Nevertheless, the effects of oxidized frying oil exposure on the activation of hepatic stellate cells (HSCs) and liver fibrosis are still unclear. In this study, we showed that exposure to oxidized frying oil enhanced the sensitivity of HSCs to transforming growth factor (TGF)-β1-induced α-smooth muscle actin (α-SMA), collagen 1a2, collagen 1a1, metalloproteinase-2, and phosphorylated smad2/3 activation. In both carbon tetrachloride (CCl₄)- and thioacetamide (TAA)-induced liver fibrosis mouse models, we showed that long-term administration of a 10% fried oil-containing diet significantly upregulated fibrogenesis genes expression and deposition of hepatic collagen. Furthermore, long-term fried oil exposure not only promoted macrophage infiltration and increased inflammatory-related gene expression, but also accumulated excess cholesterol and lipid peroxidation in the liver tissues. In conclusion, our study demonstrated that feeding a fried oil-containing diet may trigger TGF-β1-induced HSCs activation and thereby promote liver damage and fibrosis progression through enhancing the inflammatory response and lipid peroxidation.

The first study on the effect of crocodile oil from Crocodylus siamensis on hepatic mitochondrial function for energy homeostasis in rats

Background and Aim:

Consumption of fatty acids (FA) can alter hepatic energy metabolism and mitochondrial function in the liver. Crocodile oil (CO) is rich in mono-and polyunsaturated FAs, which have natural anti-inflammatory and healing properties. In rat livers, we investigated the effect of CO on mitochondrial function for energy homeostasis.

Materials and Methods:

Twenty-one male Sprague-Dawley rats were divided into three groups at random. Group 1 rats were given sterile water (RO), Group 2 rats were given CO (3% v/w), and Group 3 rats were given palm oil (PO) (3% v/w). For 7 weeks, rats were given sterile water, CO, and PO orally. The researchers looked at body weight, food intake, liver weight, energy intake, blood lipid profiles, and mitochondria-targeted metabolites in the liver. The liver’s histopathology, mitochondrial architecture, and hydrolase domain containing 3 (HDHD3) protein expression in liver mitochondria were studied.

Results:

Body weight, liver weight, liver index, dietary energy intake, and serum lipid profiles were all unaffected by CO treatment. The CO group consumed significantly less food than the RO group. The CO group also had significantly higher levels of oxaloacetate and malate than the PO group. CO treatment significantly ameliorated hepatic steatosis, as evidenced by a greater decrease in the total surface area of lipid particles than PO treatment. CO administration preserved mitochondrial morphology in the liver by upregulating the energetic maintenance protein HDHD3. Furthermore, chemical-protein interactions revealed that HDHD3 was linked to the energy homeostatic pathway.

Conclusion:

CO may benefit liver function by preserving hepatic mitochondrial architecture and increasing energy metabolic activity.

The formation, determination and health implications of polar compounds in edible oils: Current status, challenges and perspectives

To effectively control the quality of edible oil, polar compounds in edible oils have been studied extensively in the past few decades, particularly in the field of frying. This article critically reviews the formation, determination, and health implications of the polar compounds in edible oils via comprehensive literature research. The challenges and perspectives of polar compounds in edible oils are also discussed. Three chemical reactions, including oxidation, hydrolysis, and polymerization, elaborate polar compound formation. Many techniques are used to determine the total polar compound content of edible oils, with comparative analysis; Fourier transform infrared technique is a relatively ideal method. A major obstacle for nutritional studies focused on polar compounds formed during frying is that few pure compounds have been quantified. To inhibit the formation of the polar compounds effectively, investigations into the applications of enzymatic method in developing new lipophilized antioxidants may be a new direction in research.