Special section: Nutritional deficiencies. (Secci..n Especial: Deficiencias nutricionales.)

This special issue contains 23 articles that discusses the topic of diseases, nutrition, and malnutrition, especially in Mexico. Topics include the nutritional status of iron, vitamin B12, vitamin A, and anaemia in Mexican children, vitamin D status in Mexican women at reproductive age, prevalence of iron deficiency and anaemia during 2006-2018 in Mexican women 20-49 years of age, the increasing incidence of SARS-CoV- 2 in older adolescents and younger adults during the epidemic in Mexico, stakeholder analysis of the deliberation of an increase to the excise tax on sweetened beverages in Mexico, among others.