Background: Hypertriglyceridemia may contribute to hardening or thickening of the artery walls which increases the risk of stroke and heart disease. Therefore, the normal level of serum triglyceride can prevent both cardiovascular and cerebrovascular diseases. Gamma-oryzanol, a phytosterol compound presents in rice bran oil, has been shown to exhibit lipid-lowering effects in both animals and human.
Objective: To evaluate the effect of gamma-oryzanol-enriched-rice bran oil from Thai brown rice, prepared by innovation technology, on plasma triglyceride (TG) level in patients with hypertriglyceridemia.
Materials and Methods: Double-blind randomized clinical trial was carried out in 54 subjects with hypertriglyceridemia. They were divided into two groups (27 patients per group) and treated with RBOh (gamma-oryzanol-enriched rice bran oil, 20,000 ppm of gamma-oryzanol), and RBOn (cooking oil, gamma-oryzanol 5,000 ppm). The treatments were performed for 8 weeks. Physical examinations and laboratory tests were performed at weeks 0 (as baseline), 4th and 8th of the study. Lifestyle modifications were conducted in both groups.
Results: Significant reduction of plasma TG levels at the 4th and 8th weeks of the treatment were found in RBOh-treated group with p-value = 0.024 and 0.006, respectively. In RBOn-treated group, significant reduction of plasma TG and increase in HDL levels and was observed at the 4th week, but not the 8th week of the treatment, with p-value = 0.001 and 0.020, respectively. TG/HDL cholesterol ratio was significantly reduce at the 4th and 8th week in RBOh-treated group (p-value = 0.011 and 0.048, respectively) and at the 4th week in RBOn-treated group (p-value = 0.003). No serious side effects were found throughout the study period in any group of treatment.
Conclusion: Rice bran oil containing gamma oryzanol could reduce the TG level in hypertriglyceridemic patients. The RBOh, gamma oryzanol-enriched rice bran oil, showed prominent effects in reducing serum TG level and TG/HDL ratio. Therefore, RBOh intakes might be able to help prevent the occurrence of cerebrovascular and cardiovascular disease in the patients with hypertriglyceridemia.

Keywords: Hypertriglyceridemia, Rice bran oil, Gamma-oryzanol, TG/HDL ratio