Micronutrient deficiency and immunity

More than two billion people worldwide are deficient in at least one micronutrient [1,2]. Micronutrient deficiencies are sometimes referred to as hidden hunger because they are often not clinically apparent until severe; however, they can have significant health consequences even at subclinical levels [3]. Deficiency of iron, vitamin A, and zinc together account for >10% of deaths among children younger than 5 years, as well as approximately 10% of the disability-adjusted life years, that is, years of life lost because of ill health, early death, or disability among children in this age group [4]. These figures, however, do not take into full account the interaction between micronutrient deficiency and infection [5].