**5. Functional foods**

The functional food is denoted as the food with certain health beneficial function given by the pharmacologically active ingredient named "food factor." The food factors are essentially not nutrient as exemplified by polyphenols and dietary fibers, [14] but some nutrient molecules show pharmacological functions and are thus food factors [15]. For example, vitamin D [16] and omega-3 fatty acids [17] that are nutrients required as structural component of bone and cellular membranes, respectively, have other physiological functions such as immune modulation [18].

There are many types of functional foods currently in the market, which target certain abnormal physiology and disorder such as hyperglycemia, obesity, and even dementia and immune, and the forms are also variable such as fresh fruit and vegetables, processed foods, and even tablet and capsule.

In Japan, FOSHU (foods for specialized health uses) was legally approved that can claim certain health benefit such that the product is recommended to the individuals who have the signs of hyperglycemia and want to manipulate the blood sugar level [19]. FOSHU provided one model of the government regulation for developing functional foods, but there are many types of functional foods that are globally in the market such as the dietary supplements established in US, and other commonly named functional foods such as pharmafoods, nutraceuticals, and fortified foods [20].

Those functional foods distributed in the current society are contributing certain extent to the human health; however, due to the complexity such as found in above-mentioned naming and also in the usage, the social benefits of functional foods are not fully satisfied or often mislead. There are also some discussions left whether the medicinal functions of foods are simply explained by the ligand-receptor theory applied for drug action [21]. It is worthy to renovate the classification of functional foods from the view of Mibyou care.

*Mibyou Care is A Key for Healthy Life Elongation: The Role of Mibyou-Care Functional Foods DOI: http://dx.doi.org/10.5772/intechopen.101073*
