A fibre cocktail of fenugreek, guar gum and wheat bran reduces oxidative modification of LDL induced by an atherogenic diet in rats.

BACKGROUND: LDL (low-density lipoprotein) oxidation is a key trigger factor for the development of atherosclerosis. Relatively few studies exist on the impact of dietary fibre on LDL oxidation. This study was undertaken to evaluate the influence of a novel fibre mix of fenugreek seed powder, guar gum and wheat bran (Fibernat) on LDL oxidation induced by an atherogenic diet.

METHOD: Male Wistar albino rats were administered one of the following diets: (1) a control diet that was fibre-free (Group I); (2) an atherogenic diet containing 1.5% cholesterol and 0.1% cholic acid (Group II) or (3) an atherogenic diet supplemented with Fibernat (Group III). Peroxidative changes in low-density lipoprotein (LDL) and the oxidative susceptibility of LDL and the LDL + VLDL (very low-density lipoprotein) fraction were determined. As a corollary to the oxidative modification theory, the titer of autoantibodies to oxidised LDL (oxLDL) was determined at various time points of the study. In addition, plasma homocysteine (tHcy) and lipoprotein (Lp (a)), apolipoprotein (apoB), cholesterol, triglyceride, phospholipid and alpha-tocopherol content of LDL were determined.

RESULTS: A decrease in malonaldehyde (MDA) content (p<0.05) and relative electrophoretic mobility (REM) of LDL was observed in the group III rats as compared to the group II rats. An increase in lag time to oxidation (p<0.01) and decrease in maximum oxidation (p<0.01) and oxidation rate (p<0.01) were observed in the LDL + VLDL fraction of group III rats. In group II rats, formation of autoantibodies to oxLDL occurred at an earlier time point and at levels greater than in the group III rats. Fibernat, had a sparing effect on LDL alpha-tocopherol, which was about 51% higher in the group III rats than in the group II rats; apo B content of LDL was reduced by 37.6% in group III rats. LDL of group III rats displayed a decrease in free and ester cholesterol (p<0.01) as compared to that of group II. A decrease in plasma homocysteine (p<0.01) and an increase in GSH (p<0.05) were also observed in group III rats when compared with that of group II.

CONCLUSION: Fibernat administration appears to combat oxidative stress resulting in a trend to lower oxidative modification of LDL. In addition, the cholesterol and apo B content of LDL were reduced significantly with a sparing effect on LDL alpha-tocopherol. This novel fibre preparation could be an effective diet therapy and therefore needs further investigation.