Dietary parboiled rice (PR) has a low risk of disease, but little is known about the contribution of PR to the prevention of hyperlipidemia. The potential role and underlying mechanisms of PR in hyperlipidemia were evaluated in this study. Male C57BL/6J mice were fed with a normal diet, high-fat diet (HFD) containing refined rice (HFDRR) or PR (HFDPR). It was found that PR intervention improved lipid accumulation in mice. Transcriptomic data analysis revealed that 27 genes were up-regulated (mostly involved in lipid breakdown) and 86 genes were down-regulated (mostly involved in inflammatory responses) in the HFDPR group compared to the HFDRR group. And 15 differentially expressed genes (DEGs) were validated by quantitative real-time PCR (RT-qPCR), while protein interaction network showed that protein tyrosine phosphatase receptor type C (PTPRC) has a central role. The gut microbiota of mice was also altered after different dietary treatments, with higher ratio of Firmicutes and Bacteroidetes, increased abundances of Ruminococcaceae, Lachnospiraceae, Christensenellaceae, Porphyromonadaceae, Rikenellaceae and Prevotellaceae, and decreased abundances of Lactobacillaceae, Peptostreptococcaceae, Erysipelotrichaceae and Actinobacteria in the HFDRR group. In addition, it was observed that PPAR signaling pathway may act as a bridge between DEGs and differential gut microbiota. These results suggested that PR can prevent hyperlipidemia by modulating liver genes and gut microbiota.

Brown rice (BR) is a traditional health food being rich in various active substances, which have effective preventive and therapeutic effects on many diseases. In this review, we systemically summarized the efficacy of BR on cardiovascular diseases (CVDs), hyperlipidemia, hypertension, diabetes, obesity, osteoporosis, neurodegenerative diseases, cancer, immune disorders, inflammation, anxiety, liver and stomach damage, etc. Underlying mechanisms have also been analyzed, which include regulating lipid synthesis and metabolism, improving insulin levels and increasing glucose metabolism, anti-oxidation, promoting the immune system, transcription and non-transcriptional regulation, blocking cell cycle, thereby improving disease symptoms and reducing its recurrence rate. Generally, BR has been almost disappeared in modern society, but it is promising to exploit the potential to become a functional food. Further research on the nutritional value, variety differences, storage problems, taste and molecular mechanism of BR will be conducive to help meticulously design clinical intervention trials and ultimately improve the treatment and prevention of various diseases.