A rice variety (HYJA-Ri4) enhances arterial thrombus formation in an animal model of thrombosis.

Epidemiological evidence exists for a causative role of inappropriate diets in the development and clinical outcome of thrombotic diseases. Our previous studies have shown that some fruits and vegetables have antithrombotic activity. As rice is a principal ingredient of everyday food in Japan, the aim of the present study was to determine rice varieties with antithrombotic effect. Western-style high-fat diet containing flour prepared from whole-grain rice of different varieties was fed to atherosclerosis-prone (apolipoprotein E- and low density lipoprotein receptor-deficient) mice for 3 months. A laser-induced carotid-artery thrombosis model was used. None of the five tested rice varieties showed an antithrombotic effect. The effect of HYJA-Ri1, HYJA-Ri2, HYJA-Ri3 and HYJA-Ri5 rice on experimental thrombus formation did not differ significantly from the controls. However, HYJA-Ri4 rice significantly enhanced the thrombotic reaction (p = 0.0078), thus having a prothrombotic effect. Our findings suggest that HYJA-Ri4 rice should not be included in an antithrombotic diet.