With the growing health problem on obesity and its associated metabolic disorders, functional foods with hypolipidemic and body fat-lowering effects are greatly needed. The effects of instant rice made from a combination of pigmented giant embryonic rice (Keunnunjami) and white rice, in comparison with those of instant non-pigmented giant embryonic brown rice and instant ordinary brown rice, on the lipid metabolism and body weight in mice under high fat diet condition were investigated.

Male C57BL/6N mice (n=48) were given experimental diets for seven weeks: normal control (NC), high fat (HF), and HF supplemented with instant normal brown rice (HF-NB), non-pigmented giant embryonic brown rice (HF-GB), and white rice with 8% Keununnjami (HF-KJ8) or 18% Keunnunjami (HF-KJ18). Their body weight gain, plasma lipid profile, adipokine level, lipid-regulating enzymes activities, and mRNA expressions of peroxisome proliferator-activated receptors (PPARs) were determined.

At the end of the experimental period, the HF mice exhibited significantly higher body weight and fat, plasma triglyceride and total cholesterol levels, and atherogenic index and lower high-density lipoprotein cholesterol concentration than the NC group. However, diet supplementation of instant rice counteracted this high fat-induced body weight gain and hyperlipidemia through inhibition of lipogenesis and adipokine production and alteration of PPARs expressions.

The instant KJ8 and KJ18 rice showed generally similar hypolipidemic and body weight-lowering effects to instant NB and GB rice. These findings demonstrate that instant white rice with added 8% Keunnunjami may be beneficial as functional food with strong hypolipidemic and anti-obesity properties.