Growth and micronutrient needs of adolescents

Objective: This paper focuses on micronutrients in relation to needs throughout adolescence, a period which involved growth and development that occur through a complex interaction of genetic instructions, hormones and environmental influences, many of them of dietary origin. In the context of micronutrient 'needs' it is of special importance to differentiate between the 'nutritional needs' and 'metabolic needs'. Two main questions arise in relation to the micronutrient needs: (1) why are micronutrients necessary? and (2) how are their needs assessed? Results: The 'necessary' amount will differ according to the objectives pursued: (a) to achieve of growth and development; and (b) to maintain 'optimal health'. The assesment of micronutrient needs and status has proved to be difficult, but when elucidating and establishing them, it is imperative to arrive at the estimates in the light of their interdependent role in metabolism and functions. The knowledge of micronutrient metabolic needs call be approached through epidemiological observations, bioavailability studies and clinical trials. However, there is a nearly total absence of reports on the particular metabolic and dietary needs of adolescents. Conclusion: Thus more studies are required in relation to the effect of features associated with adolescence on 'needs', evaluating their impact on bioavailablility and turnover (storage and losses), and the interactions among micronutrients in the assessment of metabolic and nutritional needs. Another aim should be to establish static and functional indexes, reference values and cut-off points in adolescence, to be used in clinical and epidemiological studies. Future studies should focus on needs to determine those required to maintain 'optimal functions' and regarding the potential prevention of chronic adult diseases.