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In the 1980s, Japan proposed the terminology of 'functional food' and its concept [1], and since then the importance of conducting basic and applied studies on food functionality has been emphasized globally. Functional foods in particular as well as common foods in general are constituted with a variety of components including functional factors, and it has been recognized as difficult to evaluate their functionalities by usual chemical, biochemical and physiological methodologies [2]. Against this backdrop, nutrigenomics came into being as a new method of evaluating functional foods, as well as nutrients, in a holistic manner. Meanwhile the endowed chair, Functional Food Genomics, was established at the University of Tokyo with the aegis of 32 food companies in Japan. This academia-industry collaboration has been working well to disclose why and how some particular functional foods elicit their effects in the body. These include soy protein isolate, cocoa polyphenol, sesamin as a lignan of sesame origin, and many others. On the other hand, food safety has been gaining public attention, and we applied genomics for assessment of the wholesomeness of newly developed hypoallergenic wheat flour compared with normal flour. The application of this way of holistic evaluation suggested that the new product was basically the same as the normal product in terms of all-gene expression profiles. The same method was applied to a new sweet protein, neoculin, which resembled toxic lectins in conformation. The result indicated that neoculin had lost its lectin activity, possessing no particular toxic effect. It is thus likely that genomics can be applied to a variety of foods in general for the purpose of simultaneously assessing their functionality.

In order to clarify the physiological effects of Chlorella intake on subjects with high-risk factors for lifestyle-related diseases, we conducted Chlorella ingestion tests on 17 subjects with high-risk factors for lifestyle-related diseases and 17 healthy subjects over a 16-week period, including a 4-week post-observation period. We conducted blood biochemical tests and analyzed gene expression profile in whole blood cells in the peripheral blood before and after Chlorella intake. We confirmed that in both groups, Chlorella intake resulted in noticeable reductions in body fat percentage, serum total cholesterol, and fasting blood glucose levels. Through gene expression analysis, we found that gene expression profiles varied with Chlorella intake and identified many genes that exhibited behavior such that after the completion of the intake period, expression levels returned to pre-intake expression ones. Among these were genes related to signal transduction molecules, metabolic enzymes, receptors, transporters, and cytokines. A difference in expression level was found between the two groups at the start of the tests, and we were able to identify genes with noticeable variance in expression level resulting from Chlorella intake in the high-risk factor group. These included genes involved in fat metabolism and insulin signaling pathways, which suggests that these pathways could be physiologically affected by Chlorella intake. There were clear variations in the expression profiles of genes directly related to uptake of glucose resulting from Chlorella intake, indicating that the activation of insulin signaling pathways could be the reason for the hypoglycemic effects of Chlorella.