Current knowledge concerning optimum nutritional status of riboflavin, niacin and pyridoxine

The term 'optimum nutrition' has evolved from a perceived need to base reco mmendations for nutrient intakes firmly in the context of function. It foll ows that 'optimum nutritional status' for individual nutrients should be de fined in terms of biochemical or physiological markers having some function al value but also showing an appropriate relationship to nutrient intake. T he present short review considers the current position regarding such marke rs for riboflavin, pyridoxine and niacin. It is concluded that whilst there are several biochemical measures which respond to changes in intake of eac h of these vitamins, no single measure is wholly satisfactory as a marker o f optimum status.