In the first months of life, as the protective antibodies passed from mother to child decrease and the baby's ability to develop active immunity is not yet complete, the child falls into an "immunity gap," making them susceptible to pathogens.
Deficiencies in calcium, vitamin D, protein, magnesium, iron, and zinc can make babies fussy due to weak bones, unstable nerves, reduced immunity, and poor sleep.
Not eating a variety of foods, consuming too much added sugar and salt, and skipping breakfast are unhealthy habits that can lead to malnutrition and illness in children.