Rice Research: Open Access
Open Access

Brown Rice; Nutrigenomics; Phenolics; Rice

There are two types of brown rice, which are germinated and nongerminated. Germinated brown rice is obtained by immersing the brown rice grain in water to initiate germination [1]. The benefits of germinated brown rice are that the nutrients found in brown rice are more easily digested and the texture of brown rice is better. Germination has been employed to improve the texture of cooked brown rice. It also initiates numerous changes in the composition and chemical structure of the bioactive components. Germination could induce the formation of new bioactive compounds, such as gamma-aminobutyric acid (GABA). The consumption of germinated brown rice is increasing in many Asian countries because of its improved palatability quality and potential health-promoting functions.

Advances in the human genome era have shown that diet plays an important factor in the health and the causation chronic diseases such as type 2 diabetes. This is because the diet-genome interactions can result in changes especially in the proteome, transcriptase and metabolite. For example, current healthcare practitioners recommend brown rice to be consumed rather than white rice. This is due to the fact that brown rice is more nutritious. One common trait between white rice and brown rice is that they are both gluten free and contain no trans-fat or cholesterol [2]. Encouraging people to eat brown rice more is a difficult challenge due to its taste, which is less likeable compared to the taste of white rice. In the United States, more than 70% of rice consumed is white rice, and rice consumption has reached 9.3 kg per capita since the 1930s. In addition, the consumption of brown rice is beneficial for postprandial blood glucose control because brown rice has a lower glycaemic index than white rice.

Rice is the main staple food for more than half of the world’s population. The cereal was also utilised as a popular remedy since ancient times for several therapeutic purposes. Rice or rice-based products were also well documented in the traditional medicines of different Asian countries. The well-known popular uses are anti-diabetic, antiinflammatory for the airway, ailment of gastrointestinal disorders and diarrhoea, diuretic, source of vitamins and skin preparations [3]. One of the rice varieties, red rice Rakthashali, is a staple food in India and has been described by Ayurveda practitioners as a functional food for a number of medications. The medicinal rice Kullakar has high thiamine content, while the Karikalaveya variety is high in riboflavin and niacin.

Therefore, the aim of our work is to review the phytochemical constituents and nutrigenomic implications of brown rice in relation to animal and human studies. In addition, our work has also contributed significantly to the current understandings of brown rice with reference to the nutrigenomic implications of brown rice shown in human intervention studies. Therefore, this mini-review will provide a valuable reference resource for future studies in such areas [4].

Search Strategy

An electronic literature search was conducted using PubMed, Medline (OvidSP) Cochrane CENTRAL and Web of Science until December 2017. Additional articles were identified from references in the retrieved articles. Search terms included combinations of the following: rice, brown rice, phytochemicals, nutrigenomics and bioactives. The search was restricted to articles in English that addressed the phytochemical constituents and nutrigenomic implications of brown rice [5].

Phytochemical Compounds in Brown RiceThe advantages for health with the consumption of brown rice mainly come from the phytochemicals found in its bran layers [6]. The various parts of the rice grain. The phytochemical composition of brown rice cannot be dissociated from the scientific work of the Dutch Nobel prize scientist Christiaan Eijkman who initially reported the potential of brown rice and the story behind beriberi in humans in the previous centuries. the major phytochemical composition of brown rice. In addition to B vitamins, phytochemicals found in brown rice include dietary fibre, functional lipids, essential amino-acids, phytosterols, phenolic acids, flavonoids, anthocyanins, proanthocyanins, tocopherols, tocotrienols, minerals, gamma aminobutyric acid (GABA) and γ-oryzanol. Brown rice also contains high levels of phytic acid.

Anti-Diabetic Effect

Type 2 diabetes is a worldwide epidemic affecting millions of people across the world and associated with significant morbidity and mortality. Diet and life style factors play an important role in the pathogenicity of type 2 diabetes. Therapeutic management of the disease is only partially effective, costly and associated with adverse side effects. Therefore, scientists and healthcare professionals are looking for alternative management approaches that are safe, affordable and easily accessible to people, especially those residing in the low and middle income countries. In recent years, a considerable increase in scientific research has been observed regarding the use of brown rice for effective management of diabetes mellitus since it is the main staple food in many parts of the world, especially developing countries of Asia and Africa [7].

Several population-based studies have shown increased risk of type 2 diabetes associated with the intake of white rice, while higher dietary intake or substitution of white rice with brown rice in the diet may decrease the risk. In the same context, results of clinical studies are also encouraging. Recently, a research group in Japan has reported a significant decrease in postprandial glucose level in diabetic patients following consumption of glutinous brown rice for one day. The same group has also reported improved glycaemic control in diabetic patients even after eight weeks of ingestion of glutinous brown rice. Using an open-labelled, randomized cross-over study design, they observed a significant decrease in postprandial plasma glucose, haemoglobin A1c (HbA1c) and glycoalbumin levels in patients who ate glutinous brown rice twice a day compared to those on white rice. Another study of similar duration and dietary intervention on Japanese diabetic patients has also reported decreased levels of postprandial plasma glucose levels and improved endothelial function. However, no significant changes were observed in the HbA1c level. Similarly, a randomized controlled trial on Korean type 2 diabetic patients who followed a brown ricebased vegan diet for 12 weeks have also shown improved glycaemic control (larger reductions in HbA1c level) compared to those who followed the conventional diabetic diet [8].

Anti-Dyslipoproteinemia

Dyslipoproteinemia is a group of heterogeneous disorders characterized by elevated plasma cholesterol, triglycerides and lipoproteins level. Dyslipoproteinemia is an important risk factor for an array of clinical conditions including atherosclerosis, cardiovascular diseases and acute pancreatitis. Diet plays an important role in inducing dyslipoproteinemia as evident by the rise in the incidence of the disease due to the intake of modern diets high in fats, sugars and refined grain products. Many studies have demonstrated that brown rice also has anti-dyslipoproteinemia and cholesterol lowering effects in animal models [9].

Anti-Cancer Effect

Recent studies have reported the chemo-preventive and anticancer potential of some biologically-active molecules present in germinated brown rice. These molecules can prevent or suppress cancer development. Chemopreventive activities of germinated rough rice have been demonstrated in a recent study. Using azoxymethane, colon cancer was induced in six-week-old male Sprague-Dawley rats followed by oral administration of either control diet or different doses of germinated rough rice crude extract (2000, 1000 and 5000 mg/kg body weight) once daily for eight weeks. The study showed a dosedependent reduction in the size and number of aberrant crypt foci formation and β-catenin expression in rats fed with germinated rough rice crude extract [10].

Our review has highlighted that brown rice contains certain bioactive phytochemical compounds that might be associated with some important nutrigenomic implications. Therefore, brown rice has received increasing attention from consumers who are healthconscious. In addition, our review also suggests that there are several opportunities for the food industry to develop a wide range of food products using brown rice as the main ingredient. Similar to other plants, future research should be designed to screen for the individual bioactive components that might be associated with the nutrigenomic implications of brown rice.

I would like to thank my Professor for his support and encouragement.

The authors declare that they are no conflict of interest

1. LiuRH (2007) Whole grain phytochemicals and health. J Cereal Sci 46: 207-219.

Indexed at, Google Scholar, Crossref

2. Adom KK, Liu RH (2002) Antioxidant activity of grains. J Agric Food Chem 50: 6182-6187.

Indexed at, Google Scholar, Crossref

3. Adom KK, Sorrells ME, Liu RH (2005) Phytochemicals and antioxidant activity of milled fractions of different wheat varieties. J Agric Food Chem 53: 2297-2306.

Indexed at, Google Scholar, Crossref

Indexed at, Google Scholar, Crossref

4. Martínez , Lattimer JM, Hubach KL, Case JA, Yang J,et al. (2013) Gut microbiome composition is linked to whole grain-induced immunological improvements. ISME J 7: 269-280.

Google Scholar, Crossref

5. Tian S, Nakamura K, Kayahara H (2004) Analysis of phenolic compounds in white rice, brown rice, and germinated brown rice. J Agric Food Chem 52: 4808-4813.

Indexed at, Google Scholar, Crossref

6. Cáceres PJ, Peñas E, Martinez-Villaluenga C, Amigo L, Frias J (2017) Enhancement of biologically active compounds in germinated brown rice and the effect of sun-drying.  J Cereal Sci 73: 1-9.

Indexed at, Google Scholar, Crossref

7. Adebamowo SN, Eseyin O, Yilme S, Adeyemi D, Willett WC, et al. ( 2017) A mixed-methods study on acceptability, tolerability, and substitution of brown rice for white rice to lower blood glucose levels among Nigerian adults. Front Nutr 4: 33.

Indexed at, Google Scholar, Crossref

8. Patil SB, Khan MK (2011) Germinated brown rice as a value added rice product: A review. J Food Sci Technol 48: 661-667.

Indexed at, Google Scholar, Crossref

9. Vogt TM, Ziegler RG, Graubard BI, Swanson CA, Greenberg RS, et al. (2003) Serum selenium and risk of prostate cancer in U.S. blacks and whites. Int  J Cancer  103: 664-670.

Indexed at, Google Scholar, Crossref

10. S Dixit, A Singh, M Cruz, P Maturan, (2014) Kumar Multiple  major QTL lead to stable yield performance of rice cultivars across varying drought intensities BMC Genet 15-16

Crossref, Google Scholar