A Critique of Nutritional Recommendations

has been under constant criticism ever since its origin. One cause for this may be the somewhat conflicting experimental results, but I suggest that an even more important reason for the lack of acceptance results from the traditional conceptual approach towards nutrition. Understanding the nature of this conceptual hindrance may be relevant for the Orthomolecular school in arguing for the general acceptance of the "optimal intake" approach. The traditional approach towards nutrition is illustrated by the influential Recommended Dietary Allowances (RDA). In my opinion RDA also reflects widely accepted attitudes among people, who do not have any primary acquaintance with these recommendations. It seems reasonable to familiar-ize oneself with the basis for RDA to understand the limitations of the traditional approach. The RDA levels of intake of essential nutrients are considered "to be adequate to meet the known nutritional needs of practically all healthy persons. " (RDA, 1980, p.l). However, "nutritional need " is a vague concept and it is not defined in more detail by the RDA. The concept of "nutritional need " gives the false impression that specific amounts of nutrients are required daily, which is not the case. There is a balance in the body: all that is ingested is metabolized to other chemical forms or is excreted unaltered from the body in the long term. Larger intakes of nutrients cause faster metabolism and/or excretion. What is important, however, is that the concentrations in the body depend on intake. Larger intakes cause higher steady state concentrations. The concentrations further determine reaction rates and how the body functions. The lack of a biochemical basis for "nutri-tional need " may be understood even better by considering the physiological roles of essential nutrients (Hemila, 1984). For example, they may function as cofactors of enzymes or they may participate in nonenzymatic reactions. A number of enzymes, but not all of them, need cofactors in order to be active. Especially the B-group vitamins are transformed into cofactors in the body. A cofactor (C) binds to an inactive apoenzyme (E) an