Effect of Olive Oil on Erythrocyte Membrane Fatty Acid Contents in Hemodialysis Patients

Patients with chronic kidney disease (CKD) have higher mortality rate than general population. Especially, the most common cause of mortality was known as cardiovascular disease that account for almost 50 percent in patients with dialysis. Mediterranean diet was reported for lowering risk of coronary artery disease in general population. Mediterranean diet is not acceptable in CKD patients because of restriction of potassium, phosphorus, and protein.

Relatively proper food among Mediterranean diet for hemodialysis patients is olive oil. Many researchers usually preferred olive oil as control group for evaluating effect of omega-3 fatty acid. However, previous studies reported that control groups using olive oil of 3g in a day have shown increased components of omega-3 fatty acid such as eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA). Therefore, cardioprotective effect of olive oil may be associated with increasing of omega-3 fatty acid levels.

Fatty acid contents of erythrocyte membrane as a biomarker that reveals status of fatty acid within recent 3 months. Omega-3 fatty acid such as EPA or DHA, omega-3 index that calculated by sum of EPA and DHA, and ratio of EPA/arachidonic aicd (AA) are frequently reported as important biomarkers of its association with cardiovascular accidents. One of the fatty acid contents of erythrocyte membrane, oleic acid was increased in patients with acute coronary disease compared to control group. Oleic acid of erythrocyte membrane in hemodialysis patients with taking omega-3 was significantly decreased compared to group with taking olive oil. In addition, control group using olive oil was also meaningfully decreased erythrocyte membrane oleic acid compared to baseline levels. In this way, olive oil seemed to have similar effect as omega-3 fatty acid. supplement of enough amount olive oil with balanced meal may show similar effect of omega-3 fatty acid supplementation.

It is ideal way to intake olive oil in uncooked state with vegetables or breads, but practically peoples stir-fry or fry foods in olive oil instead of cooking oil. Ignition point of olive oil is 185-205 degrees of Celsius with depending on its oxidation degrees. There is a study that the contents of vitamin C in broccoli were scantly changed when broccoli was stir-fried in olive oil. It needs to identify the change of erythrocyte membrane contents between taking uncooked or natural olive oil and taking fried or stir fried olive oil with other foods. Taking meals with olive oil can change erythrocyte membrane fatty acid contents including oleic acid in hemodialysis patients.

Eligibility Criteria:
Inclusion Criteria:

* Over 20 years and under 80 years , men and women who are undergoing hemodialysis at least 6months
* Agree to participate in the clinical trial

Exclusion Criteria:

* Use of omega-3 fatty acid currently or within 3 months
* Intake over 10 gram of olive oil three times a week within 3 months
* Admitted to the hospital with cardiovascular or infectious disease within 3months
* Pregnant or expected to be pregnant
* Accompanied Liver cirrhosis or malignant tumor
* Serum albumin \< 3.0 g/dL at the time of inclusion