Cultural adaptation and content validity evidence of the Nutritional Literacy Scale Brazilian version

To investigate the evidence of content validity and reliability of the Brazilian version of the Nutritional Literacy Scale (NLS) after the cultural adaptation process. Psychometric study of 1,197 users of the National Health Service (Brazilian SUS). The NLS was culturally adapted to Brazilian Portuguese and six items of the original scale were modified to improve its understanding, giving rise to the Brazilian version of the scale named NLS-BR. The analysis of evidence of content validity of the NLS-BR was performed using the Item Response Theory (IRT). The final version of the NLS-BR had 23 items and proved to be adequate to assess nutritional literacy in adults assisted by the Brazilian SUS. The NLS-BR proved to be of adequate understanding and demonstrated evidence of content validity and reliability for users of the Brazilian SUS.