Healthy life with three functions of foods

Abstract

Foods have three functions, i.e, nutritional, sensory and physiological functions. First two functions are long known and have been well studied. Physiological function was found recently in late 1980s in Japan as a function to keep healthy condition or prevent disease of the people. This discovery soon evoked vigorous basic, and then, applied research activities in Japan. Many physiological functions have been found and numerous food components have been reported to show physiological function(s). Physiological functions hitherto known can be classified into five categories; to prevent disease such as hypertension, diabetes and cancer, to help absorption of minerals such as iron and calcium, to increase immune activity, to protect oxidation and to relax mental stress. The idea of functional food was soon appeared that was defined as food products prepared by adding special food component(s) and have scientific evidence to show the expected physiological function. This led a flood of various kinds of functional foods in the market. In 1991 the Japanese Government started an approved system of "Foods for Special Health Use (FOSHU)". To be approved as FOSHU and to carry FOSHU label with their products the manufacturer must file evidences in the levels of test tube, animal experiment and clinical trial. Since the start of this system the number of approved foods increased gradually and reached 754 items at the end of 2007. The annual sales of FOSHU reached 53 trillion $ in 2005. Physiological functions to be approved as FOSHU can be grouped into seven claims. Mechanisms of function are explained with some food materials approved as FOSHU. Fructo-oligosaccharides were proven to be utilized only by Bifidobacterium among bacterial flora in our intestine. Intake of these sugars increases the number of Bifidobacterium, which exert beneficial effects on our intestine. Trehalose helps absorption of calcium as it is utilized by Bifidobacterium to produce short chain fatty acids in large intestine. These acids make calcium ions soluble to be absorbed easily. 1,3-Diacylglycerol are approved to inhibit the accumulation of fat in the body. 1-Acylglycerol produced from this compound is difficult to be reconstruct into triacylglycerol different from 2-acylglycerol produced from cooking oil. It was suggested, however, that it is not clever way to depend on functional foods to keep our health. The most important point for this purpose, is to take variety of foods, to take balance of three functions of foods.