Perante os dados gratificantes relativamente à capacidade dos fitonutriementos promoverem a saúde, parece cada vez mais pertinente o enriquecimento de alimentos nestas substâncias. O desenvolvimento da genética aliada à
engenharia biotecnológica vão ser ferramentas essenciais para concretizar o objectivo de aumentar o aporte dos alimentos em fitonutrimentos17911801.
Como produtos secundários do metabolismo das plantas, os fitonutrimentos são o resultado de complexas vias de biossíntese, ainda desconhecidas, o que por si representa um obstáculo à concretização das expectativas dos biólogos. Estão já documentadas algumas técnicas, ainda em desenvolvimento e que requerem alguns ajustes, mas que já produziram resultados positivos. Uma técnica comum é a adição do composto que pretendemos obter no produto final, ao germoplasma. Aqui, pressupõe-se que a planta adulta vai ser rica no fitonutrimento inicialmente incorporado1791.
A mutagénese induzida, tem como fundamento alterar determinados genes, para que possam exprimir à célula um incremento das proteínas relacionadas com a síntese de determinados fitonutrimentos. Esta técnica ainda não é muito usada, devido ao seu insucesso1801.
Mais recentemente procede-se à clonagem de enzimas chave que participam no mecanismo da biossíntese dos fitonutrimentos. Ao clonar estas enzimas, permite fazer a sua reprodução em laboratório, e incorporá-las nas células vegetais de modo a aumentar o seu pool na célula, o que favorece uma maior produção de fitonutrimentos e tem a vantagem de não ser necessário conhecer exactamente todos os mecanismos envolvidos na biossíntese1801. São estes alguns exemplos
de como a importância dos fitonutrimentos se repercute na engenharia biotecnológica, de modo a tornar os produtos vegetais ricos nestes compostos[351[361[79][801.
O meu objectivo, ao elaborar uma dissertação relativa aos fitonutrimentos, era dar a conhecer um pouco mais estas substâncias, actual objecto de investigação, face à sua crescente importância como protectoras da doença e promotoras da saúde. Os estudos clínicos sucedem-se uns aos outros, e é emergente o investimento que se está a depositar nestes compostos. Áreas como a Medicina, Nutrição, Farmacologia, e até a Indústria Alimentar debruçam-se sobre o estudo dos fitonutrimentos.
Apesar de tudo, este tema é algo difícil de abordar, por diversas razões, mas sobretudo porque são inúmeros os compostos que existem na Natureza, o que me obrigou a seleccionar aqueles sobre os quais há mais informação, e porque o desconhecimento sobre os seus mecanismos de acção ainda é muito grande. Muito do conhecimento actual sobre os fitonutrientes ainda se baseia no campo das hipóteses e, por esta razão, a controvérsia paira sobre este tema. Os fitonutrimentos são contestados por muitos, existindo uma certa incredibilidade sobre os efeitos reais destas substâncias. As experiências em humanos são ainda escassas, e aquelas realizadas com animais também não fornecem resultados muito concretos.
Os estudos recentes comprovam as propriedades bioactivas favoráveis dos fitonutrimentos. Estes dados da investigação científica têm apontado fortemente na possibilidade destas substâncias exercerem funções "chave" no organismo, que impeçam a progressão de doenças crónicas como cancro, doenças cardiovasculares, obesidade, diabetes e dislipidemias. O estudo dos fitonutrimentos são uma área de pesquisa futura, e a modificação genética dos alimentos para optimizar a saúde representa uma nove fronteira na ciência da Nutrição.
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