Composition differences between organic and conventional processed foods: a meta-analytical study

Comparisons between the nutritional quality of organic and conventional fresh foods are frequently reported in the literature; however, discussion about processed foods is less frequent. Therefore, this study compared the nutritional content of processed products from both production systems using a systematic review of the literature and meta-analysis, regarding aspects of raw material management and processing. The study reviewed scientific articles published between 2010 and 2020 and the data obtained were analyzed using the standardized mean difference method with Hedges’ adjustment and a random analytical model. Thirty-seven articles were selected, and the foods analyzed in the studies were grouped into five categories: meat products, dairy products, caught fish, wines, and fruit juices/pulps. In products of animal origin, the comparative focus shown was mainly that of the fatty acid profile, while in those of vegetable origin it was that of phytochemicals. Related to the comparison of nutrient contents, it was possible to verify the similarities in organic and conventional products in most studies; however, specific differences were verified (P < 0.05): organics contained more proteins (meat), omega 3 (dairy), and less linoleic acid (dairy and caught fish). Also, there were differences in the management of organic and conventional raw materials, and similarities in processing. Therefore, the choice for organic processed foods should not be made exclusively based on nutritional aspects, considering that the differences in nutrient contents in relation to those of conventional products are practically nonexistent. RESUMO: Frequentemente são encontradas na literatura comparações entre a qualidade nutricional dos alimentos orgânicos e convencionais in natura, no entanto, pouco se discute acerca dos processados. Assim sendo, o objetivo desse estudo foi comparar o teor nutricional dos processados de ambos os sistemas de produção utilizando uma revisão sistemática da literatura e meta-análise, associando a aspectos de manejo das matérias-primas e processamento. Para isso, buscou-se artigos científicos publicados entre 2010 e 2020 e os dados obtidos foram analisados utilizando o método da diferença média padronizada com ajuste de Hedges e modelo analítico aleatório. Trinta e sete artigos foram selecionados, e os alimentos analisados em tais estudos foram agrupados em cinco categorias: cárneos, lácteos, pescado, vinhos e sucos/polpas de frutas. Nos produtos d