Effect of stir-fried versus non-stir-fried olive oil in cooked food on erythrocyte membrane fatty acid composition in hemodialysis patients: a randomized controlled trial

Background Individuals receiving maintenance hemodialysis (HD) are at particularly high risk for cardiovascular disease. Although olive oil intake has been associated with cardiovascular benefits, the effects of stir-fried olive oil on erythrocyte membrane fatty acid (FA) composition in patients undergoing HD have not been adequately investigated. This study aimed to compare the effects of stir-fried and non-stir-fried olive oil on changes in erythrocyte membrane FA composition in patients undergoing HD. Methods In this single-blind randomized trial, 31 patients undergoing HD received lunch meals containing extra virgin olive oil for 12 weeks. Meals were prepared using one of two methods: the olive oil was either used during stir-frying or added after cooking without heat exposure. Erythrocyte membrane FA profiles were assessed at baseline and after the 12-week intervention using gas chromatography. Results A total of 27 participants completed the study. Overall caloric intake and animal-derived lipid intake did not differ between the groups. In the stir-fried olive oil group, erythrocyte membrane trans-oleic acid levels increased significantly after 12 weeks. In contrast, the non-stir-fried olive oil group showed significant increases in saturated FAs, including stearic acid, along with a higher arachidonic acid-to-eicosapentaenoic acid ratio and increased serum albumin levels. Conclusions Stir-fried olive oil increased trans-oleic acid levels in erythrocyte membrane FA composition, whereas non-stir-fried olive oil improved serum albumin levels. These findings suggest that preparation methods may be as important as the oil itself, with non-stir-fried olive oil offering a potentially useful nutritional strategy for patients undergoing HD.