**1. Introduction**

Lifestyle-related diseases, obesity, metabolic syndrome and cancer are now a global health problem, and the countermeasures are a global issue. Changes of our dietary habits such as increasing intake of refined sugar and polished rice largely account for the high prevalence of non-communicable chronic diseases, indicating the importance of minor food ingredients [1]. Then, improvement of the dietary habits is probably one of the best ways to decrease the risk of such diseases. Brown rice is a traditional food in Japan, and contains ordinary nutrients and many kinds of minor nutrients such as vitamins and minerals. It also contains biologically active components such as plant polyphenols and phytic acid, especially in its bran [1, 2]. Certain components in brown rice such as γ-oryzanol, have been demonstrated to show inhibitory effects on obesity and diabetes including the detailed mechanisms as described below. We should understand the benefits of such minor but biologically active ingredients, and incorporate it to our usual diet. Traditional foods are often produced by utilizing microorganisms-mediated fermentation. As well as minor bioactive components, fermented foods are attracting attentions as

health-promoting functional foods. It is possible that new bioactive components produced during fermentation may promote human health.

In this chapter, I will first introduce biological activities of brown rice or its components. Next, I will mention about fermented brown rice, its components and biological activities, including our recent research result about "Brown rice and rice bran fermented with *Aspergillus oryzae* (FBRA)". FBRA is a processed food, rich in partially digested fiber, rice bran-derived phytic acid, and free phenolic compounds. We and other research groups have examined various biological activities of FBRA and reported its anti-tumorigenic, anti-inflammatory, and other effects in cultured cells and/or animal disease models. I will give an outline of the characteristic of this processed brown rice, and then I will introduce our recent work about "Preventive effect of FBRA on spontaneous type 1 diabetes in NOD female mice". How to estimate the *in vivo* effect of dietary FBRA on type 1 diabetes model, its possible mechanisms and the limit of this study will be described.
