Intake of heat-expanded amaranth grain reverses endothelial dysfunction in hypercholesterolemic rabbits

This study reports the new functional property of amaranth grain against diet-induced endothelial dysfunction in rabbits. Twenty-seven New Zealand rabbits were fed either a standard diet (SD/G1) or a hypercholesterolemic diet (Hichol) for 28 days. On day 29, the Hichol group was subdivided into four groups and begun receiving the following diets for 21 days: G2: SD + amaranth, G3: Hichol + amaranth, G4: SD alone, and G5: Hichol alone, while G1 continued to receive SD for 21 days. Amaranth intake restored endothelial function (G2, G3) to nearly normal during the 21-day recovery besides substantially lowering total and LDL blood cholesterol levels. This effect was not seen by simply correcting the diet (G4). Upon continuance of Hichol, however, amaranth supplementation did show some contribution to the cholesterol-lowering effect (G4 vs. G3). On day 49, feeding Hichol without the help of amaranth, harm was further magnified by lowering HDL-cholesterol (G5). Fecal cholesterol was found increased in groups that ingested amaranth (G2, G3), but no significant impact from either supplementation or diet reversal was found in fecal bile acids. Amaranth supplementation granted some protection against tissue cholesterol (G5) and tissue peroxidation (G3). It is concluded that even in concurrence with a hypercholesterolemic diet, intake of heat-expanded amaranth can revert an associated endothelial dysfunction besides incrementing fecal cholesterol excretion and lowering blood and tissue cholesterol oxidation in dyslipidemic rabbits. These results supported the notion of a lipid peroxidation process occurring with high cholesterol intakes.