――Please tell us about the 'third function' of foods (that of controlling physical conditions).
As you may know, foods contain many kinds of nutritional constituents that work on the human body in diverse ways, such as maintenance of health. Regarding the functions of foods, these can be categorized into three groups. The first is to maintain life through various nutritional elements (the primary function); secondly, the nutritional elements appeal to the senses of a living organism (the second function); and, thirdly, the function controls physical conditions (the third condition). The function of nutrition in foods (primary function) and that of gustatory sensation (second function) have been sufficiently investigated and are well recognized. Lately, the third function, which includes powers such as biophylaxis, or a power for protecting a living body, the control of physical conditions and prevention of diseases, all of which foods possess, is highlighted.
Investigation of the third function of foods is crucial to maintaining and enhancing health. It is, therefore, considered that a variety of foods will be produced with the third function taken into consideration. In these years, illnesses that are referred to as life-style related diseases, including diabetes and cancer, have increased, pushing up medical expenses and becoming a serious issue. In order to prevent such sicknesses, it would be very important to take foods on a daily basis which have the third function.
――Please explain how foods with the third function are defined.
What is included in the definition of the functional foods is "Foods that have been designed and processed to adequately express functions relating to control of physical conditions in living bodies, such functions including biophylactic function, adjustment of physical conditions and biorhythm, and prevention of and recovery from diseases, all of which is in the components of foods." Now the Ministry of Health and Welfare has approved "food for specified health use." This covers materials used regularly as foods, and whose shapes and methods of intake are almost the same as other food taken every day.
The Ministry set up a food labelling system in 1991. Under that system, foods for which some functions are recognized are referred to as "food for specified health use," and the nutritional labelling of such food has been regulated. Considering the background that led to setting up the system, there were recent situations where foods with a claim of health effects came to be popularly distributed, based on a rich background of scientific information. This rule has been brought into effect with the objective that these foods are positioned as being "food for specified health use"; people can properly choose any such foods for managing and controlling their health and this arrangement contributes to an improvement in nutritional conditions.
――Now, prevention of life-style related diseases by diet is widely publicised lately. Is there anything that we have to bear in mind in this regard?
Drugs play a major role in treating and improving various diseases. In order to prevent illness in daily lives, it is important to have in our diet take foods with their nutritional value taken into consideration. Nutritional elements contained in foods can be one of the indications for assessing the functions of foods. Since April of this year, it has become obligatory to label the nutrient components in foods. Many kinds of food with labelling of nutritional constituents have been on sale at storefronts, increasing in variety year by year. However, there were many cases in which the mode of labelling varied with each company or manufaturer, and where the ingredients labelled were unclear. In order to correct the situation, a section of the Nutrition Improvement Law was revised in 1995, by which a system called "Standardisation for Nutrition Labelling" was introduced.
Labelling of protein, fat, carbohydrate, inorganic substances, vitamins and calorific value has become compulsory under this system. As for the regulation of labelling in order to emphasize contents of nutrient elements, such as high or low content of nutritional constituents, there is a rule requiring that the amounts of such elements have to be above or below designated values. In the case of calcium, for example, content has to be more than 180mg per 100g when labelling as "rich in calcium" or "calcium enriched" is used. Regarding terminology such as "low," "reduced" or "cut," the use of these words is not allowed unless the calorific value of the food referred to is less than 40Kcal per 100g. Labelling as such can be one of the quantitative factors for heath control through food intake. It is important to use the labelling intelligently in one's daily dietary habit, with awareness of what it means.
In addition, the Ministry has been making positive efforts in the labelling of patient foods since April of this year. Labelling for patients' use has already been allowed for certain foods, such as those for a low sodium diet, that have met the necessary standards. The Ministry established a policy of approving labelling for patients' use, provided that 1) for foods which are used for alimentotherapy or dietary therapy in treatment of diabetes and renal disease, the basis of positive effects which can be expected has been clarified from the standpoints of medicine and nutritional science; and 2) the safety aspects of the food or component have already been recognized.
――Can we expect that we may be able to prevent diseases through taking foods (or functional foods)?
Since last April, some vitamins are categorized as food. The Japanese tend to regard components that have effects and efficacy as a kind of drug. However, there could situations where illness can be improved by the nutritional constituents of foods. I think that the distinction between "food and drugs including quasi drugs" will have to be reviewed as soon as possible. Meanwhile, medicine labelled as "nourishing tonic" is being distributed. However, the points emphasized belong to a subject of nutrition through dieting, relating originally to foods. I believe that in the future it will be necessary for dietitians to be allowed to deal not only with vitamins but also with mineral nutrition. I hope that people will use foods intelligently, whose functions are known so as to improve nutritional status and help prevent diseases.