Growth and micronutrient needs of adolescents

Objective: This paper focuses on micronutrients in relation to needs throug hout adolescence, a period which involved growth and development that occur through a complex interaction of genetic instructions, hormones and enviro nmental influences, many of them of dietary origin. In the context of micro nutrient 'needs' it is of special importance to differentiate between the ' nutritional needs' and 'metabolic needs'. Two main questions arise in relat ion 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 pur sued: (a) to achieve of growth and development; and (b) to maintain 'optima l 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 metab olism and functions. The knowledge of micronutrient metabolic needs call be approached through epidemiological observations, bioavailability studies a nd 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 fea tures associated with adolescence on 'needs', evaluating their impact on bi oavailablility and turnover (storage and losses), and the interactions amon g micronutrients in the assessment of metabolic and nutritional needs. Anot her aim should be to establish static and functional indexes, reference val ues and cut-off points in adolescence, to be used in clinical and epidemiol ogical studies. Future studies should focus on needs to determine those req uired to maintain 'optimal functions' and regarding the potential preventio n of chronic adult diseases.