Similar cholesterol-lowering properties of rice bran oil, with varied gamma-oryzanol, in mildly hypercholesterolemic men

Eur J Nutr. 2005 Mar;44(3):163-73. doi: 10.1007/s00394-004-0508-9. Epub 2004 May 19.


Background: The cholesterol lowering properties of rice bran oil (RBO) containing differing amounts of non-saponifiable components have not been studied in humans, to our knowledge.

Aim of the study: To evaluate cholesterol lowering effects of RBO, with low and high amounts of gamma-oryzanol (ferulated plant sterols) in mildly hypercholesterolemic men.

Methods: Mildly hypercholesterolemic men, 38-64 y, starting cholesterol 4.9-8.4 mmol/l (n = 30), consumed 50 g/d peanut oil (PNO) in vehicles for 2 wks during a run-in period, then, without wash-out, were randomly equilibrated (based on initial level of cholesterol) into two groups to consume 50 g/d RBO low (0.05 g/d) or high (0.8 g/d) gamma-oryzanol for 4 wks, in a randomized, controlled, parallel design study. Subjects were free-living and consumed habitual diets with some restrictions. Plasma concentrations of total, LDL-,HDL-cholesterol and triacylglycerol were measured at base line and after 2, 4, and 6 wks.

Results: The two RBO types were not significantly different with respect to effects on various cholesterol parameters, at 2 and 4 wks, including total cholesterol, LDL-, HDL- and LDL/HDL cholesterol ratio. Low and high gamma-oryzanolcontaining RBO feeding for 4 wks lowered total plasma cholesterol (6.3 %), LDL-C (10.5 %) and the LDL-C/HDL-C ratio (18.9 %).

Conclusions: RBO supplementation at ca. 50% total fat intake improved lipoprotein pattern in mildly hypercholesterolemic men. Methylated sterols in gamma-oryzanol are thought to be largely ineffective at inhibiting dietary cholesterol absorption, but could enhance cholesterol-lowering ability of 4-desmethylsterols. Assuming all ferulated sterols become de-ferulated in the gut, low and high gamma-oryzanolcontaining RBOs provided intestinal loads of 453 and 740 mg/d free 4-desmethylsterols, respectively. This intestinal load of 453-740 mg/d of efficacious free plant sterol equivalents had identical effects on lipoproteins.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Anticholesteremic Agents / therapeutic use*
  • Cholesterol / blood
  • Cholesterol, HDL / blood
  • Cholesterol, LDL / blood
  • Dose-Response Relationship, Drug
  • Humans
  • Hypercholesterolemia / blood
  • Hypercholesterolemia / drug therapy*
  • Male
  • Middle Aged
  • Phenylpropionates / therapeutic use*
  • Phytotherapy*
  • Plant Oils / chemistry*
  • Rice Bran Oil
  • Triglycerides / blood


  • Anticholesteremic Agents
  • Cholesterol, HDL
  • Cholesterol, LDL
  • Phenylpropionates
  • Plant Oils
  • Triglycerides
  • Cholesterol
  • Rice Bran Oil
  • gamma-oryzanol